{"id":820,"date":"2025-01-04T22:25:10","date_gmt":"2025-01-04T14:25:10","guid":{"rendered":"https:\/\/www.ikaros.love\/?p=820"},"modified":"2025-01-04T22:25:10","modified_gmt":"2025-01-04T14:25:10","slug":"java%e5%a4%9a%e7%ba%bf%e7%a8%8b%e5%90%8c%e6%ad%a5","status":"publish","type":"post","link":"https:\/\/www.ikaros.love\/?p=820","title":{"rendered":"java\u591a\u7ebf\u7a0b\u540c\u6b65"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"512\" height=\"512\" src=\"https:\/\/www.ikaros.love\/wp-content\/uploads\/2025\/01\/401.png\" alt=\"\" class=\"wp-image-821\" srcset=\"https:\/\/www.ikaros.love\/wp-content\/uploads\/2025\/01\/401.png 512w, https:\/\/www.ikaros.love\/wp-content\/uploads\/2025\/01\/401-300x300.png 300w, https:\/\/www.ikaros.love\/wp-content\/uploads\/2025\/01\/401-150x150.png 150w, https:\/\/www.ikaros.love\/wp-content\/uploads\/2025\/01\/401-200x200.png 200w\" sizes=\"(max-width: 512px) 100vw, 512px\" \/><\/figure>\n\n\n\n<p>\u7ebf\u7a0b\u540c\u6b65\u662f\u4e2a\u5f88\u56f0\u96be\u7684\u5b9e\u73b0\uff0c\u56e0\u4e3a\u5e76\u884c\u6d89\u53ca\u5230\u4e0d\u540c\u8d44\u6e90\u5bf9\u540c\u4e00\u4e2a\u8d44\u6e90\u7684\u8bbf\u95ee\u7ade\u4e89\uff0c\u540c\u4e00\u4e2a\u8d44\u6e90\u5728\u4e0d\u540c\u8fdb\u7a0b\u4e2d\u7684\u7f13\u5b58\u901f\u5ea6\u5f71\u54cd\uff0c\u4e0d\u540c\u7ebf\u7a0b\u5bf9\u62a2\u593a\u8d44\u6e90\u7684\u5b89\u6392\uff0c\u7b49\u5f85\uff0c\u5524\u9192\uff0c\u987a\u5e8f\uff0c\u7b49\u7b49\u7b49\uff0c\u5c5e\u5b9e\u9700\u8981\u5927\u7bc7\u6765\u8bb2\u89e3\u3002<\/p>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-pale-pink-color\">\u7b2c\u4e00\u6b65\uff1asynchronized\u5173\u952e\u5b57\u548c<code><strong>volatile<\/strong><\/code>\u5173\u952e\u5b57<\/mark><\/p>\n\n\n\n<p><code>synchronized<\/code> \u662f Java \u4e2d\u7528\u4e8e\u5b9e\u73b0\u7ebf\u7a0b\u540c\u6b65\u7684\u5173\u952e\u5b57\u3002\u5b83\u786e\u4fdd\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u5bf9\u5171\u4eab\u8d44\u6e90\u7684\u8bbf\u95ee\u662f\u5b89\u5168\u7684\uff0c\u907f\u514d\u4e86\u6570\u636e\u4e0d\u4e00\u81f4\u7684\u95ee\u9898\u3002\u4ee5\u4e0b\u662f <code>synchronized<\/code> \u7684\u8be6\u7ec6\u89e3\u6790\uff1a<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u57fa\u672c\u6982\u5ff5\u548c\u539f\u7406<\/h3>\n\n\n\n<ul>\n<li><strong>\u540c\u6b65\u65b9\u6cd5<\/strong>\uff1a\u901a\u8fc7\u5728\u65b9\u6cd5\u58f0\u660e\u4e2d\u4f7f\u7528 <code>synchronized<\/code> \u5173\u952e\u5b57\u6765\u5b9e\u73b0\u3002\u56e0\u4e3a\u8be5\u5173\u952e\u5b57\u662fjava\u8bed\u8a00\u5c42\u9762\u7684\u5b9e\u73b0\u6240\u4ee5\u4e0d\u7528\u6355\u83b7\u5f02\u5e38\u3002\u4e5f\u4e0d\u7528\u5173\u5fc3\u5e95\u5c42\u5b9e\u73b0\u3002<\/li>\n\n\n\n<li><strong>\u540c\u6b65\u4ee3\u7801\u5757<\/strong>\uff1a\u901a\u8fc7\u5728\u4ee3\u7801\u5757\u4e2d\u4f7f\u7528 <code>synchronized<\/code> \u5173\u952e\u5b57\u6765\u5b9e\u73b0\u3002\u7406\u89e3<code>synchronized<\/code>\u5757\u7684\u5de5\u4f5c\u539f\u7406\u5bf9\u4e8e\u786e\u4fdd\u7ebf\u7a0b\u5b89\u5168\u81f3\u5173\u91cd\u8981\u3002<code>synchronized<\/code>\u5757\u7684\u4e3b\u8981\u4f5c\u7528\u662f<strong>\u4e92\u65a5\u8bbf\u95ee <\/strong>\uff0c\u5373\u5728\u540c\u4e00\u65f6\u95f4\u53ea\u5141\u8bb8\u4e00\u4e2a\u7ebf\u7a0b\u8fdb\u5165\u4e34\u754c\u533a\uff08critical section\uff09<\/li>\n\n\n\n<li><strong>\u9501\u5bf9\u8c61<\/strong>\uff1a<code>synchronized<\/code> \u5173\u952e\u5b57\u9700\u8981\u4e00\u4e2a\u5bf9\u8c61\u4f5c\u4e3a\u9501\uff0c\u8fd9\u4e2a\u5bf9\u8c61\u53ef\u4ee5\u662f\u4efb\u4f55\u5bf9\u8c61\uff0c\u4f46\u901a\u5e38\u662f\u5f53\u524d\u5bf9\u8c61\uff08<code>this<\/code>\uff09\u6216\u67d0\u4e2a\u7279\u5b9a\u7684\u5bf9\u8c61\u3002<\/li>\n\n\n\n<li><strong>\u4e92\u65a5 <\/strong>\uff08Mutual Exclusion\uff09\u662f\u6307\u5728\u540c\u4e00\u65f6\u95f4\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u80fd\u591f\u8bbf\u95ee\u67d0\u4e2a\u8d44\u6e90\u6216\u6267\u884c\u67d0\u4e2a\u4ee3\u7801\u6bb5\u3002\u4e92\u65a5\u7684\u4e3b\u8981\u76ee\u7684\u662f\u9632\u6b62\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u4fee\u6539\u5171\u4eab\u6570\u636e\uff0c\u4ece\u800c\u907f\u514d\u6570\u636e\u7ade\u4e89\uff08race condition\uff09\u548c\u4e0d\u4e00\u81f4\u7684\u95ee\u9898\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u786e\u5b9e\uff0c<code>volatile<\/code>\u5173\u952e\u5b57\u5728Java\u4e2d\u7528\u4e8e\u89e3\u51b3\u5171\u4eab\u53d8\u91cf\u5728\u7ebf\u7a0b\u95f4\u7684\u53ef\u89c1\u6027\u95ee\u9898\u3002\u4e0b\u9762\u662f\u5bf9<code>volatile<\/code>\u5173\u952e\u5b57\u7684\u8be6\u7ec6\u89e3\u91ca\uff0c\u5305\u62ec\u5176\u5de5\u4f5c\u539f\u7406\u3001\u9002\u7528\u573a\u666f\u4ee5\u53ca\u4e0e<code>synchronized<\/code>\u7684\u533a\u522b\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u4ec0\u4e48\u662f<code>volatile<\/code>\u5173\u952e\u5b57\uff1f<\/h3>\n\n\n\n<p><code>volatile<\/code>\u5173\u952e\u5b57\u662f\u4e00\u4e2a\u7279\u6b8a\u7684\u4fee\u9970\u7b26\uff0c\u53ef\u4ee5\u5e94\u7528\u4e8e\u53d8\u91cf\u4e0a\u3002\u5f53\u4e00\u4e2a\u53d8\u91cf\u88ab\u58f0\u660e\u4e3a<code>volatile<\/code>\u65f6\uff0c\u5b83\u5177\u6709\u4ee5\u4e0b\u7279\u6027\uff1a<\/p>\n\n\n\n<ol>\n<li><strong>\u53ef\u89c1\u6027<\/strong>\uff1a\u786e\u4fdd\u4e00\u4e2a\u7ebf\u7a0b\u5bf9<code>volatile<\/code>\u53d8\u91cf\u7684\u4fee\u6539\u5bf9\u5176\u4ed6\u7ebf\u7a0b\u662f\u7acb\u5373\u53ef\u89c1\u7684\u3002<\/li>\n\n\n\n<li><strong>\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f<\/strong>\uff1a\u9632\u6b62\u7f16\u8bd1\u5668\u548c\u5904\u7406\u5668\u5bf9<code>volatile<\/code>\u53d8\u91cf\u7684\u8bfb\u5199\u64cd\u4f5c\u8fdb\u884c\u91cd\u6392\u5e8f\u3002<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">\u5de5\u4f5c\u539f\u7406<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">\u53ef\u89c1\u6027<\/h4>\n\n\n\n<p>\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\uff0c\u6bcf\u4e2a\u7ebf\u7a0b\u90fd\u6709\u81ea\u5df1\u7684\u5de5\u4f5c\u5185\u5b58\uff08\u4e5f\u79f0\u4e3a\u7ebf\u7a0b\u6808\uff09\uff0c\u5f53\u7ebf\u7a0b\u8bbf\u95ee\u4e00\u4e2a\u53d8\u91cf\u65f6\uff0c\u901a\u5e38\u662f\u4ece\u81ea\u5df1\u7684\u5de5\u4f5c\u5185\u5b58\u4e2d\u8bfb\u53d6\u3002\u800c\u5de5\u4f5c\u5185\u5b58\u4e2d\u7684\u6570\u636e\u662f\u4ece\u4e3b\u5185\u5b58\uff08\u4e5f\u79f0\u4e3a\u5806\u5185\u5b58\uff09\u4e2d\u590d\u5236\u8fc7\u6765\u7684\u3002\u5982\u679c\u6ca1\u6709\u7279\u6b8a\u63aa\u65bd\uff0c\u4e00\u4e2a\u7ebf\u7a0b\u5bf9\u5171\u4eab\u53d8\u91cf\u7684\u4fee\u6539\u4e0d\u4f1a\u7acb\u5373\u53cd\u6620\u5230\u5176\u4ed6\u7ebf\u7a0b\u7684\u5de5\u4f5c\u5185\u5b58\u4e2d\u3002<\/p>\n\n\n\n<p><code>volatile<\/code>\u5173\u952e\u5b57\u901a\u8fc7\u786e\u4fdd\u5bf9<code>volatile<\/code>\u53d8\u91cf\u7684\u8bfb\u5199\u64cd\u4f5c\u76f4\u63a5\u5728\u4e3b\u5185\u5b58\u4e2d\u8fdb\u884c\uff0c\u4ece\u800c\u4fdd\u8bc1\u4e86\u53d8\u91cf\u7684\u53ef\u89c1\u6027\u3002\u5177\u4f53\u6765\u8bf4\uff1a<\/p>\n\n\n\n<ul>\n<li>\u5f53\u4e00\u4e2a\u7ebf\u7a0b\u4fee\u6539\u4e86<code>volatile<\/code>\u53d8\u91cf\u7684\u503c\u65f6\uff0c\u8fd9\u4e2a\u4fee\u6539\u4f1a\u7acb\u5373\u5237\u65b0\u5230\u4e3b\u5185\u5b58\u3002<\/li>\n\n\n\n<li>\u5f53\u5176\u4ed6\u7ebf\u7a0b\u9700\u8981\u8bfb\u53d6\u8fd9\u4e2a<code>volatile<\/code>\u53d8\u91cf\u65f6\uff0c\u5b83\u4eec\u4f1a\u4ece\u4e3b\u5185\u5b58\u4e2d\u8bfb\u53d6\u6700\u65b0\u7684\u503c\uff0c\u800c\u4e0d\u662f\u4ece\u5404\u81ea\u7684\u5de5\u4f5c\u5185\u5b58\u4e2d\u8bfb\u53d6\u65e7\u503c\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f<\/h4>\n\n\n\n<p>\u7f16\u8bd1\u5668\u548c\u5904\u7406\u5668\u4e3a\u4e86\u4f18\u5316\u6027\u80fd\uff0c\u53ef\u80fd\u4f1a\u5bf9\u4ee3\u7801\u8fdb\u884c\u6307\u4ee4\u91cd\u6392\u5e8f\u3002\u4f8b\u5982\uff0c\u7f16\u8bd1\u5668\u53ef\u80fd\u4f1a\u5c06\u4e24\u4e2a\u4e0d\u76f8\u5173\u7684\u64cd\u4f5c\u4ea4\u6362\u987a\u5e8f\uff0c\u4ee5\u63d0\u9ad8\u6307\u4ee4\u6d41\u6c34\u7ebf\u7684\u6548\u7387\u3002\u7136\u800c\uff0c\u8fd9\u79cd\u91cd\u6392\u5e8f\u53ef\u80fd\u4f1a\u5bfc\u81f4\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u51fa\u73b0\u4e0d\u53ef\u9884\u6d4b\u7684\u884c\u4e3a\u3002<\/p>\n\n\n\n<p><code>volatile<\/code>\u5173\u952e\u5b57\u901a\u8fc7\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f\u6765\u4fdd\u8bc1\u4ee5\u4e0b\u4e24\u70b9\uff1a<\/p>\n\n\n\n<ul>\n<li>\u5bf9<code>volatile<\/code>\u53d8\u91cf\u7684\u5199\u64cd\u4f5c\u4e0d\u4f1a\u88ab\u91cd\u6392\u5e8f\u5230\u5199\u64cd\u4f5c\u4e4b\u524d\u3002<\/li>\n\n\n\n<li>\u5bf9<code>volatile<\/code>\u53d8\u91cf\u7684\u8bfb\u64cd\u4f5c\u4e0d\u4f1a\u88ab\u91cd\u6392\u5e8f\u5230\u8bfb\u64cd\u4f5c\u4e4b\u540e\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u786e\u4fdd\u4e86\u5bf9<code>volatile<\/code>\u53d8\u91cf\u7684\u64cd\u4f5c\u6309\u7167\u7a0b\u5e8f\u4e2d\u6307\u5b9a\u7684\u987a\u5e8f\u8fdb\u884c\uff0c\u907f\u514d\u4e86\u7531\u4e8e\u91cd\u6392\u5e8f\u5bfc\u81f4\u7684\u4e0d\u4e00\u81f4\u6027\u95ee\u9898\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u9002\u7528\u573a\u666f<\/h3>\n\n\n\n<p><code>volatile<\/code>\u5173\u952e\u5b57\u9002\u7528\u4e8e\u4ee5\u4e0b\u573a\u666f\uff1a<\/p>\n\n\n\n<ol>\n<li><strong>\u72b6\u6001\u6807\u5fd7<\/strong>\uff1a<ul><li>\u7528\u4e8e\u8868\u793a\u67d0\u4e2a\u72b6\u6001\u6216\u6807\u5fd7\u4f4d\uff0c\u4f8b\u5982\u7ebf\u7a0b\u662f\u5426\u5e94\u8be5\u7ee7\u7eed\u8fd0\u884c\u3002<\/li><\/ul><code>volatile boolean running = true;<\/code><\/li>\n\n\n\n<li><strong>\u5355\u4f8b\u6a21\u5f0f<\/strong>\uff1a<ul><li>\u5728\u53cc\u91cd\u68c0\u67e5\u9501\u5b9a\uff08Double-Checked Locking\uff09\u6a21\u5f0f\u4e2d\uff0c\u7528\u4e8e\u786e\u4fdd\u5b9e\u4f8b\u7684\u53ef\u89c1\u6027\u548c\u4e00\u81f4\u6027\u3002<\/li><\/ul><code>private static volatile Singleton instance; public static Singleton getInstance() { if (instance == null) { synchronized (Singleton.class) { if (instance == null) { instance = new Singleton(); } } } return instance; }<\/code><\/li>\n\n\n\n<li><strong>\u914d\u7f6e\u53c2\u6570<\/strong>\uff1a\n<ul>\n<li>\u7528\u4e8e\u5b58\u50a8\u914d\u7f6e\u53c2\u6570\uff0c\u8fd9\u4e9b\u53c2\u6570\u53ef\u80fd\u4f1a\u5728\u8fd0\u884c\u65f6\u88ab\u5916\u90e8\u7cfb\u7edf\u4fee\u6539\u3002<br><code>java volatile int configValue;<\/code><\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e0e<code>synchronized<\/code>\u7684\u533a\u522b<\/h3>\n\n\n\n<p>\u867d\u7136<code>volatile<\/code>\u548c<code>synchronized<\/code>\u90fd\u53ef\u4ee5\u7528\u4e8e\u89e3\u51b3\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u7684\u5e76\u53d1\u95ee\u9898\uff0c\u4f46\u5b83\u4eec\u7684\u4f5c\u7528\u548c\u4f7f\u7528\u573a\u666f\u6709\u6240\u4e0d\u540c\uff1a<\/p>\n\n\n\n<ol>\n<li><strong><code>volatile<\/code><\/strong>:\n<ul>\n<li><strong>\u53ef\u89c1\u6027<\/strong>\uff1a\u786e\u4fdd\u53d8\u91cf\u7684\u4fee\u6539\u5bf9\u6240\u6709\u7ebf\u7a0b\u7acb\u5373\u53ef\u89c1\u3002<\/li>\n\n\n\n<li><strong>\u539f\u5b50\u6027<\/strong>\uff1a\u4ec5\u9002\u7528\u4e8e\u5355\u4e2a\u53d8\u91cf\u7684\u8bfb\u5199\u64cd\u4f5c\uff0c\u4e0d\u80fd\u4fdd\u8bc1\u590d\u5408\u64cd\u4f5c\u7684\u539f\u5b50\u6027\u3002<\/li>\n\n\n\n<li><strong>\u6027\u80fd<\/strong>\uff1a\u5f00\u9500\u8f83\u5c0f\uff0c\u9002\u7528\u4e8e\u5bf9\u6027\u80fd\u8981\u6c42\u8f83\u9ad8\u7684\u573a\u666f\u3002<\/li>\n\n\n\n<li><strong>\u9002\u7528\u573a\u666f<\/strong>\uff1a\u9002\u7528\u4e8e\u72b6\u6001\u6807\u5fd7\u3001\u914d\u7f6e\u53c2\u6570\u7b49\u7b80\u5355\u573a\u666f\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>synchronized<\/code><\/strong>:\n<ul>\n<li><strong>\u53ef\u89c1\u6027<\/strong>\uff1a\u786e\u4fdd\u53d8\u91cf\u7684\u4fee\u6539\u5bf9\u6240\u6709\u7ebf\u7a0b\u7acb\u5373\u53ef\u89c1\u3002<\/li>\n\n\n\n<li><strong>\u539f\u5b50\u6027<\/strong>\uff1a\u4fdd\u8bc1\u590d\u5408\u64cd\u4f5c\u7684\u539f\u5b50\u6027\uff0c\u53ef\u4ee5\u786e\u4fdd\u591a\u4e2a\u64cd\u4f5c\u4f5c\u4e3a\u4e00\u4e2a\u6574\u4f53\u88ab\u6267\u884c\u3002<\/li>\n\n\n\n<li><strong>\u6027\u80fd<\/strong>\uff1a\u5f00\u9500\u8f83\u5927\uff0c\u9002\u7528\u4e8e\u5bf9\u6570\u636e\u4e00\u81f4\u6027\u8981\u6c42\u8f83\u9ad8\u7684\u573a\u666f\u3002<\/li>\n\n\n\n<li><strong>\u9002\u7528\u573a\u666f<\/strong>\uff1a\u9002\u7528\u4e8e\u9700\u8981\u4fdd\u8bc1\u590d\u5408\u64cd\u4f5c\u539f\u5b50\u6027\u7684\u590d\u6742\u573a\u666f\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">\u793a\u4f8b\u4ee3\u7801<\/h3>\n\n\n\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u793a\u4f8b\uff0c\u5c55\u793a\u4e86<code>volatile<\/code>\u5173\u952e\u5b57\u7684\u4f7f\u7528\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class VolatileExample {\n    private static volatile boolean running = true;\n\n    public static void main(String&#91;] args) throws InterruptedException {\n        Thread workerThread = new Thread(() -&gt; {\n            int i = 0;\n            while (running) {\n                i++;\n                System.out.println(i);\n                try {\n                    Thread.sleep(100);\n                } catch (InterruptedException e) {\n                    e.printStackTrace();\n                }\n            }\n            System.out.println(\"Worker thread stopped.\");\n        });\n\n        workerThread.start();\n\n        Thread.sleep(2000); \/\/ \u8ba9workerThread\u8fd0\u884c2\u79d2\n        running = false; \/\/ \u4fee\u6539volatile\u53d8\u91cf\n        System.out.println(\"Main thread set running to false.\");\n    }\n}<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0c<code>running<\/code>\u53d8\u91cf\u88ab\u58f0\u660e\u4e3a<code>volatile<\/code>\uff0c\u786e\u4fdd\u4e3b\u7ebf\u7a0b\u5bf9<code>running<\/code>\u53d8\u91cf\u7684\u4fee\u6539\u80fd\u591f\u7acb\u5373\u5bf9<code>workerThread<\/code>\u53ef\u89c1\uff0c\u4ece\u800c\u4f7f\u5f97<code>workerThread<\/code>\u80fd\u591f\u53ca\u65f6\u505c\u6b62\u8fd0\u884c\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u603b\u7ed3<\/h3>\n\n\n\n<ul>\n<li><strong>\u53ef\u89c1\u6027<\/strong>\uff1a<code>volatile<\/code>\u786e\u4fdd\u5bf9\u53d8\u91cf\u7684\u4fee\u6539\u5bf9\u6240\u6709\u7ebf\u7a0b\u7acb\u5373\u53ef\u89c1\u3002<\/li>\n\n\n\n<li><strong>\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f<\/strong>\uff1a<code>volatile<\/code>\u7981\u6b62\u5bf9\u53d8\u91cf\u7684\u8bfb\u5199\u64cd\u4f5c\u8fdb\u884c\u91cd\u6392\u5e8f\u3002<\/li>\n\n\n\n<li><strong>\u9002\u7528\u573a\u666f<\/strong>\uff1a\u9002\u7528\u4e8e\u72b6\u6001\u6807\u5fd7\u3001\u914d\u7f6e\u53c2\u6570\u7b49\u7b80\u5355\u573a\u666f\u3002<\/li>\n\n\n\n<li><strong>\u4e0e<code>synchronized<\/code>\u7684\u533a\u522b<\/strong>\uff1a<code>volatile<\/code>\u4ec5\u4fdd\u8bc1\u53ef\u89c1\u6027\u548c\u7981\u6b62\u91cd\u6392\u5e8f\uff0c\u4e0d\u4fdd\u8bc1\u590d\u5408\u64cd\u4f5c\u7684\u539f\u5b50\u6027\uff1b<code>synchronized<\/code>\u4fdd\u8bc1\u53ef\u89c1\u6027\u3001\u539f\u5b50\u6027\u548c\u590d\u5408\u64cd\u4f5c\u7684\u987a\u5e8f\u6027\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u540c\u6b65\u65b9\u6cd5<\/h3>\n\n\n\n<p>\u8ba9\u7ebf\u7a0b\u81ea\u5df1\u9009\u62e9\u9501\u5bf9\u8c61\u5f80\u5f80\u4f1a\u4f7f\u5f97\u4ee3\u7801\u903b\u8f91\u6df7\u4e71\uff0c\u4e5f\u4e0d\u5229\u4e8e\u5c01\u88c5\u3002\u66f4\u597d\u7684\u65b9\u6cd5\u662f\u628a<code>synchronized<\/code>\u903b\u8f91\u5c01\u88c5\u8d77\u6765\u3002\u4f8b\u5982\uff0c\u6211\u4eec\u7f16\u5199\u4e00\u4e2a\u8ba1\u6570\u5668\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Counter {\n    private int count = 0;\n\n    public void add(int n) {\n        synchronized(this) {\n            count += n;\n        }\n    }\n\n    public void dec(int n) {\n        synchronized(this) {\n            count -= n;\n        }\n    }\n\n    public int get() {\n        return count;\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u8fd9\u6837\u4e00\u6765\uff0c\u7ebf\u7a0b\u8c03\u7528<code>add()<\/code>\u3001<code>dec()<\/code>\u65b9\u6cd5\u65f6\uff0c\u5b83\u4e0d\u5fc5\u5173\u5fc3\u540c\u6b65\u903b\u8f91\uff0c\u56e0\u4e3a<code>synchronized<\/code>\u4ee3\u7801\u5757\u5728<code>add()<\/code>\u3001<code>dec()<\/code>\u65b9\u6cd5\u5185\u90e8\u3002\u5e76\u4e14\uff0c\u6211\u4eec\u6ce8\u610f\u5230\uff0c<code>synchronized<\/code>\u9501\u4f4f\u7684\u5bf9\u8c61\u662f<code>this<\/code>\uff0c\u5373\u5f53\u524d\u5b9e\u4f8b\uff0c\u8fd9\u53c8\u4f7f\u5f97\u521b\u5efa\u591a\u4e2a<code>Counter<\/code>\u5b9e\u4f8b\u7684\u65f6\u5019\uff0c\u5b83\u4eec\u4e4b\u95f4\u4e92\u4e0d\u5f71\u54cd\uff0c\u53ef\u4ee5\u5e76\u53d1\u6267\u884c\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var c1 = Counter();\nvar c2 = Counter();\n\n\/\/ \u5bf9c1\u8fdb\u884c\u64cd\u4f5c\u7684\u7ebf\u7a0b:\nnew Thread(() -&gt; {\n    c1.add();\n}).start();\nnew Thread(() -&gt; {\n    c1.dec();\n}).start();\n\n\/\/ \u5bf9c2\u8fdb\u884c\u64cd\u4f5c\u7684\u7ebf\u7a0b:\nnew Thread(() -&gt; {\n    c2.add();\n}).start();\nnew Thread(() -&gt; {\n    c2.dec();\n}).start();\n<\/code><\/pre>\n\n\n\n<p>\u73b0\u5728\uff0c\u5bf9\u4e8e<code>Counter<\/code>\u7c7b\uff0c\u591a\u7ebf\u7a0b\u53ef\u4ee5\u6b63\u786e\u8c03\u7528\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u4e00\u4e2a\u7c7b\u88ab\u8bbe\u8ba1\u4e3a\u5141\u8bb8\u591a\u7ebf\u7a0b\u6b63\u786e\u8bbf\u95ee\uff0c\u6211\u4eec\u5c31\u8bf4\u8fd9\u4e2a\u7c7b\u5c31\u662f\u201c\u7ebf\u7a0b\u5b89\u5168\u201d\u7684\uff08thread-safe\uff09\uff0c\u4e0a\u9762\u7684<code>Counter<\/code>\u7c7b\u5c31\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002Java\u6807\u51c6\u5e93\u7684<code>java.lang.StringBuffer<\/code>\u4e5f\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002<\/p>\n\n\n\n<p>\u8fd8\u6709\u4e00\u4e9b\u4e0d\u53d8\u7c7b\uff0c\u4f8b\u5982<code>String<\/code>\uff0c<code>Integer<\/code>\uff0c<code>LocalDate<\/code>\uff0c\u5b83\u4eec\u7684\u6240\u6709\u6210\u5458\u53d8\u91cf\u90fd\u662f<code>final<\/code>\uff0c\u591a\u7ebf\u7a0b\u540c\u65f6\u8bbf\u95ee\u65f6\u53ea\u80fd\u8bfb\u4e0d\u80fd\u5199\uff0c\u8fd9\u4e9b\u4e0d\u53d8\u7c7b\u4e5f\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002<\/p>\n\n\n\n<p>\u6700\u540e\uff0c\u7c7b\u4f3c<code>Math<\/code>\u8fd9\u4e9b\u53ea\u63d0\u4f9b\u9759\u6001\u65b9\u6cd5\uff0c\u6ca1\u6709\u6210\u5458\u53d8\u91cf\u7684\u7c7b\uff0c\u4e5f\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002<\/p>\n\n\n\n<p>\u9664\u4e86\u4e0a\u8ff0\u51e0\u79cd\u5c11\u6570\u60c5\u51b5\uff0c\u5927\u90e8\u5206\u7c7b\uff0c\u4f8b\u5982<code>ArrayList<\/code>\uff0c\u90fd\u662f\u975e\u7ebf\u7a0b\u5b89\u5168\u7684\u7c7b\uff0c\u6211\u4eec\u4e0d\u80fd\u5728\u591a\u7ebf\u7a0b\u4e2d\u4fee\u6539\u5b83\u4eec\u3002\u4f46\u662f\uff0c\u5982\u679c\u6240\u6709\u7ebf\u7a0b\u90fd\u53ea\u8bfb\u53d6\uff0c\u4e0d\u5199\u5165\uff0c\u90a3\u4e48<code>ArrayList<\/code>\u662f\u53ef\u4ee5\u5b89\u5168\u5730\u5728\u7ebf\u7a0b\u95f4\u5171\u4eab\u7684\u3002<\/p>\n\n\n\n<p>\u8be6\u89e3\u4e00\u4e0bfinal\u5bf9\u8c61\u4e3a\u4ec0\u4e48\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002<\/p>\n\n\n\n<p>\u4e00\u4e9b\u4eba\u53ef\u80fd\u4f1a\u7591\u60d1\uff1aString\u5bf9\u8c61\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u56e0\u4e3a\u662ffinal\u7684\uff0c\u5bf9String\u5bf9\u8c61\u66f4\u6539\u4e0d\u662f\u66f4\u6539String\uff0c\u800c\u662f\u65b0\u5efa\u4e00\u4e2aString\u5bf9\u8c61\uff0c\u7136\u540e\u6307\u5411\u4ed6\uff0c\u8fd9\u4e9b\u5bf9\u8c61\u5b58\u50a8\u5728\u7ebf\u7a0b\u6c60\u4e2d\uff0c\u4f46\u662f\u540c\u65f6\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u5bf9String s = \u201chello\u201d\u7684s\u4fee\u6539\uff0c\u4e5f\u4e0d\u80fd\u4fdd\u8bc1\u7ebf\u7a0b\u5b89\u5168\uff0c\u4e3a\u4ec0\u4e48\u4f1a\u8bf4\u8fd9\u7c7bfinal\u5bf9\u8c61\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u5462\uff1f<\/p>\n\n\n\n<p>\u7b54\uff1a\u7ebf\u7a0b\u5b89\u5168\u6307\u7684\u662fString s = &#8220;hello&#8221;\u4e2d\u7684hello\u800c\u4e0d\u662fs\uff0c\u5b89\u5168\u7684\u662fhello\u800c\u4e0d\u662f\u6307\u5411hello\u7684\u5f15\u7528s\uff0c\u5f15\u7528\u4e0d\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002<\/p>\n\n\n\n<p>Java\u7684\u7ebf\u7a0b\u9501\u662f\u53ef\u91cd\u5165\u7684\u9501\u3002<\/p>\n\n\n\n<p>\u4ec0\u4e48\u662f\u53ef\u91cd\u5165\u7684\u9501\uff1f\u6211\u4eec\u8fd8\u662f\u6765\u770b\u4f8b\u5b50\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Counter {\n    private int count = 0;\n\n    public synchronized void add(int n) {\n        if (n &lt; 0) {\n            dec(-n);\n        } else {\n            count += n;\n        }\n    }\n\n    public synchronized void dec(int n) {\n        count += n;\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u89c2\u5bdf<code>synchronized<\/code>\u4fee\u9970\u7684<code>add()<\/code>\u65b9\u6cd5\uff0c\u4e00\u65e6\u7ebf\u7a0b\u6267\u884c\u5230<code>add()<\/code>\u65b9\u6cd5\u5185\u90e8\uff0c\u8bf4\u660e\u5b83\u5df2\u7ecf\u83b7\u53d6\u4e86\u5f53\u524d\u5b9e\u4f8b\u7684<code>this<\/code>\u9501\u3002\u5982\u679c\u4f20\u5165\u7684<code>n &lt; 0<\/code>\uff0c\u5c06\u5728<code>add()<\/code>\u65b9\u6cd5\u5185\u90e8\u8c03\u7528<code>dec()<\/code>\u65b9\u6cd5\u3002\u7531\u4e8e<code>dec()<\/code>\u65b9\u6cd5\u4e5f\u9700\u8981\u83b7\u53d6<code>this<\/code>\u9501\uff0c\u73b0\u5728\u95ee\u9898\u6765\u4e86\uff1a<\/p>\n\n\n\n<p>\u5bf9\u540c\u4e00\u4e2a\u7ebf\u7a0b\uff0c\u80fd\u5426\u5728\u83b7\u53d6\u5230\u9501\u4ee5\u540e\u7ee7\u7eed\u83b7\u53d6\u540c\u4e00\u4e2a\u9501\uff1f<\/p>\n\n\n\n<p>\u7b54\u6848\u662f\u80af\u5b9a\u7684\u3002JVM\u5141\u8bb8\u540c\u4e00\u4e2a\u7ebf\u7a0b\u91cd\u590d\u83b7\u53d6\u540c\u4e00\u4e2a\u9501\uff0c\u8fd9\u79cd\u80fd\u88ab\u540c\u4e00\u4e2a\u7ebf\u7a0b\u53cd\u590d\u83b7\u53d6\u7684\u9501\uff0c\u5c31\u53eb\u505a<strong>\u53ef\u91cd\u5165\u9501<\/strong>\u3002<\/p>\n\n\n\n<p>\u7531\u4e8eJava\u7684\u7ebf\u7a0b\u9501\u662f\u53ef\u91cd\u5165\u9501\uff0c\u6240\u4ee5\uff0c\u83b7\u53d6\u9501\u7684\u65f6\u5019\uff0c\u4e0d\u4f46\u8981\u5224\u65ad\u662f\u5426\u662f\u7b2c\u4e00\u6b21\u83b7\u53d6\uff0c\u8fd8\u8981\u8bb0\u5f55\u8fd9\u662f\u7b2c\u51e0\u6b21\u83b7\u53d6\u3002\u6bcf\u83b7\u53d6\u4e00\u6b21\u9501\uff0c\u8bb0\u5f55+1\uff0c\u6bcf\u9000\u51fa<code>synchronized<\/code>\u5757\uff0c\u8bb0\u5f55-1\uff0c\u51cf\u52300\u7684\u65f6\u5019\uff0c\u624d\u4f1a\u771f\u6b63\u91ca\u653e\u9501\u3002<\/p>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-pale-pink-color\">\u7b2c\u4e8c\u6b65\uff1a\u7406\u89e3\u548c\u907f\u514d\u6b7b\u9501<\/mark><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u6b7b\u9501<\/h3>\n\n\n\n<p>\u4e00\u4e2a\u7ebf\u7a0b\u53ef\u4ee5\u83b7\u53d6\u4e00\u4e2a\u9501\u540e\uff0c\u518d\u7ee7\u7eed\u83b7\u53d6\u53e6\u4e00\u4e2a\u9501\u3002\u4f8b\u5982\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public void add(int m) {\n    synchronized(lockA) { \/\/ \u83b7\u5f97lockA\u7684\u9501\n        this.value += m;\n        synchronized(lockB) { \/\/ \u83b7\u5f97lockB\u7684\u9501\n            this.another += m;\n        } \/\/ \u91ca\u653elockB\u7684\u9501\n    } \/\/ \u91ca\u653elockA\u7684\u9501\n}\n\npublic void dec(int m) {\n    synchronized(lockB) { \/\/ \u83b7\u5f97lockB\u7684\u9501\n        this.another -= m;\n        synchronized(lockA) { \/\/ \u83b7\u5f97lockA\u7684\u9501\n            this.value -= m;\n        } \/\/ \u91ca\u653elockA\u7684\u9501\n    } \/\/ \u91ca\u653elockB\u7684\u9501\n}\n<\/code><\/pre>\n\n\n\n<p>\u5728\u83b7\u53d6\u591a\u4e2a\u9501\u7684\u65f6\u5019\uff0c\u4e0d\u540c\u7ebf\u7a0b\u83b7\u53d6\u591a\u4e2a\u4e0d\u540c\u5bf9\u8c61\u7684\u9501\u53ef\u80fd\u5bfc\u81f4\u6b7b\u9501\u3002\u5bf9\u4e8e\u4e0a\u8ff0\u4ee3\u7801\uff0c\u7ebf\u7a0b1\u548c\u7ebf\u7a0b2\u5982\u679c\u5206\u522b\u6267\u884c<code>add()<\/code>\u548c<code>dec()<\/code>\u65b9\u6cd5\u65f6\uff1a<\/p>\n\n\n\n<ul>\n<li>\u7ebf\u7a0b1\uff1a\u8fdb\u5165<code>add()<\/code>\uff0c\u83b7\u5f97<code>lockA<\/code>\uff1b<\/li>\n\n\n\n<li>\u7ebf\u7a0b2\uff1a\u8fdb\u5165<code>dec()<\/code>\uff0c\u83b7\u5f97<code>lockB<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u968f\u540e\uff1a<\/p>\n\n\n\n<ul>\n<li>\u7ebf\u7a0b1\uff1a\u51c6\u5907\u83b7\u5f97<code>lockB<\/code>\uff0c\u5931\u8d25\uff0c\u7b49\u5f85\u4e2d\uff1b<\/li>\n\n\n\n<li>\u7ebf\u7a0b2\uff1a\u51c6\u5907\u83b7\u5f97<code>lockA<\/code>\uff0c\u5931\u8d25\uff0c\u7b49\u5f85\u4e2d\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u6b64\u65f6\uff0c\u4e24\u4e2a\u7ebf\u7a0b\u5404\u81ea\u6301\u6709\u4e0d\u540c\u7684\u9501\uff0c\u7136\u540e\u5404\u81ea\u8bd5\u56fe\u83b7\u53d6\u5bf9\u65b9\u624b\u91cc\u7684\u9501\uff0c\u9020\u6210\u4e86\u53cc\u65b9\u65e0\u9650\u7b49\u5f85\u4e0b\u53bb\uff0c\u8fd9\u5c31\u662f\u6b7b\u9501\u3002<\/p>\n\n\n\n<p>\u6b7b\u9501\u53d1\u751f\u540e\uff0c\u6ca1\u6709\u4efb\u4f55\u673a\u5236\u80fd\u89e3\u9664\u6b7b\u9501\uff0c\u53ea\u80fd\u5f3a\u5236\u7ed3\u675fJVM\u8fdb\u7a0b\u3002<\/p>\n\n\n\n<p>\u56e0\u6b64\uff0c\u5728\u7f16\u5199\u591a\u7ebf\u7a0b\u5e94\u7528\u65f6\uff0c\u8981\u7279\u522b\u6ce8\u610f\u9632\u6b62\u6b7b\u9501\u3002\u56e0\u4e3a\u6b7b\u9501\u4e00\u65e6\u5f62\u6210\uff0c\u5c31\u53ea\u80fd\u5f3a\u5236\u7ed3\u675f\u8fdb\u7a0b\u3002<\/p>\n\n\n\n<p>\u90a3\u4e48\u6211\u4eec\u5e94\u8be5\u5982\u4f55\u907f\u514d\u6b7b\u9501\u5462\uff1f\u7b54\u6848\u662f\uff1a\u7ebf\u7a0b\u83b7\u53d6\u9501\u7684\u987a\u5e8f\u8981\u4e00\u81f4\u3002\u5373\u4e25\u683c\u6309\u7167\u5148\u83b7\u53d6<code>lockA<\/code>\uff0c\u518d\u83b7\u53d6<code>lockB<\/code>\u7684\u987a\u5e8f\uff0c\u6539\u5199<code>dec()<\/code>\u65b9\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public void dec(int m) {\n    synchronized(lockA) { \/\/ \u83b7\u5f97lockA\u7684\u9501\n        this.value -= m;\n        synchronized(lockB) { \/\/ \u83b7\u5f97lockB\u7684\u9501\n            this.another -= m;\n        } \/\/ \u91ca\u653elockB\u7684\u9501\n    } \/\/ \u91ca\u653elockA\u7684\u9501\n}\n<\/code><\/pre>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-pale-pink-color\">\u7b2c\u4e09\u6b65\uff1a\u591a\u7ebf\u7a0b\u534f\u8c03<\/mark><\/p>\n\n\n\n<p>\u5728Java\u7a0b\u5e8f\u4e2d\uff0c<code>synchronized<\/code>\u89e3\u51b3\u4e86\u591a\u7ebf\u7a0b\u7ade\u4e89\u7684\u95ee\u9898\u3002\u4f8b\u5982\uff0c\u5bf9\u4e8e\u4e00\u4e2a\u4efb\u52a1\u7ba1\u7406\u5668\uff0c\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u5f80\u961f\u5217\u4e2d\u6dfb\u52a0\u4efb\u52a1\uff0c\u53ef\u4ee5\u7528<code>synchronized<\/code>\u52a0\u9501\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>class TaskQueue {\n    Queue&lt;String&gt; queue = new LinkedList&lt;&gt;();\n\n    public synchronized void addTask(String s) {\n        this.queue.add(s);\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u4f46\u662f<code>synchronized<\/code>\u5e76\u6ca1\u6709\u89e3\u51b3\u591a\u7ebf\u7a0b\u534f\u8c03\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n<p>\u4ecd\u7136\u4ee5\u4e0a\u9762\u7684<code>TaskQueue<\/code>\u4e3a\u4f8b\uff0c\u6211\u4eec\u518d\u7f16\u5199\u4e00\u4e2a<code>getTask()<\/code>\u65b9\u6cd5\u53d6\u51fa\u961f\u5217\u7684\u7b2c\u4e00\u4e2a\u4efb\u52a1\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>class TaskQueue {\n    Queue&lt;String&gt; queue = new LinkedList&lt;&gt;();\n\n    public synchronized void addTask(String s) {\n        this.queue.add(s);\n    }\n\n    public synchronized String getTask() {\n        while (queue.isEmpty()) {\n        }\n        return queue.remove();\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u4e0a\u8ff0\u4ee3\u7801\u770b\u4e0a\u53bb\u6ca1\u6709\u95ee\u9898\uff1a<code>getTask()<\/code>\u5185\u90e8\u5148\u5224\u65ad\u961f\u5217\u662f\u5426\u4e3a\u7a7a\uff0c\u5982\u679c\u4e3a\u7a7a\uff0c\u5c31\u5faa\u73af\u7b49\u5f85\uff0c\u76f4\u5230\u53e6\u4e00\u4e2a\u7ebf\u7a0b\u5f80\u961f\u5217\u4e2d\u653e\u5165\u4e86\u4e00\u4e2a\u4efb\u52a1\uff0c<code>while()<\/code>\u5faa\u73af\u9000\u51fa\uff0c\u5c31\u53ef\u4ee5\u8fd4\u56de\u961f\u5217\u7684\u5143\u7d20\u4e86\u3002<\/p>\n\n\n\n<p>\u4f46\u5b9e\u9645\u4e0a<code>while()<\/code>\u5faa\u73af\u6c38\u8fdc\u4e0d\u4f1a\u9000\u51fa\u3002\u56e0\u4e3a\u7ebf\u7a0b\u5728\u6267\u884c<code>while()<\/code>\u5faa\u73af\u65f6\uff0c\u5df2\u7ecf\u5728<code>getTask()<\/code>\u5165\u53e3\u83b7\u53d6\u4e86<code>this<\/code>\u9501\uff0c\u5176\u4ed6\u7ebf\u7a0b\u6839\u672c\u65e0\u6cd5\u8c03\u7528<code>addTask()<\/code>\uff0c\u56e0\u4e3a<code>addTask()<\/code>\u6267\u884c\u6761\u4ef6\u4e5f\u662f\u83b7\u53d6<code>this<\/code>\u9501\u3002<\/p>\n\n\n\n<p>\u56e0\u6b64\uff0c\u6267\u884c\u4e0a\u8ff0\u4ee3\u7801\uff0c\u7ebf\u7a0b\u4f1a\u5728<code>getTask()<\/code>\u4e2d\u56e0\u4e3a\u6b7b\u5faa\u73af\u800c100%\u5360\u7528CPU\u8d44\u6e90\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u6df1\u5165\u601d\u8003\u4e00\u4e0b\uff0c\u6211\u4eec\u60f3\u8981\u7684\u6267\u884c\u6548\u679c\u662f\uff1a<\/p>\n\n\n\n<ul>\n<li>\u7ebf\u7a0b1\u53ef\u4ee5\u8c03\u7528<code>addTask()<\/code>\u4e0d\u65ad\u5f80\u961f\u5217\u4e2d\u6dfb\u52a0\u4efb\u52a1\uff1b<\/li>\n\n\n\n<li>\u7ebf\u7a0b2\u53ef\u4ee5\u8c03\u7528<code>getTask()<\/code>\u4ece\u961f\u5217\u4e2d\u83b7\u53d6\u4efb\u52a1\u3002\u5982\u679c\u961f\u5217\u4e3a\u7a7a\uff0c\u5219<code>getTask()<\/code>\u5e94\u8be5\u7b49\u5f85\uff0c\u76f4\u5230\u961f\u5217\u4e2d\u81f3\u5c11\u6709\u4e00\u4e2a\u4efb\u52a1\u65f6\u518d\u8fd4\u56de\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u56e0\u6b64\uff0c\u591a\u7ebf\u7a0b\u534f\u8c03\u8fd0\u884c\u7684\u539f\u5219\u5c31\u662f\uff1a\u5f53\u6761\u4ef6\u4e0d\u6ee1\u8db3\u65f6\uff0c\u7ebf\u7a0b\u8fdb\u5165\u7b49\u5f85\u72b6\u6001\uff1b\u5f53\u6761\u4ef6\u6ee1\u8db3\u65f6\uff0c\u7ebf\u7a0b\u88ab\u5524\u9192\uff0c\u7ee7\u7eed\u6267\u884c\u4efb\u52a1\u3002<\/p>\n\n\n\n<p>\u5bf9\u4e8e\u4e0a\u8ff0<code>TaskQueue<\/code>\uff0c\u6211\u4eec\u5148\u6539\u9020<code>getTask()<\/code>\u65b9\u6cd5\uff0c\u5728\u6761\u4ef6\u4e0d\u6ee1\u8db3\u65f6\uff0c\u7ebf\u7a0b\u8fdb\u5165\u7b49\u5f85\u72b6\u6001\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public synchronized String getTask() {\n    while (queue.isEmpty()) {\n        this.wait();\n    }\n    return queue.remove();\n}\n<\/code><\/pre>\n\n\n\n<p>\u5f53\u4e00\u4e2a\u7ebf\u7a0b\u6267\u884c\u5230<code>getTask()<\/code>\u65b9\u6cd5\u5185\u90e8\u7684<code>while<\/code>\u5faa\u73af\u65f6\uff0c\u5b83\u5fc5\u5b9a\u5df2\u7ecf\u83b7\u53d6\u5230\u4e86<code>this<\/code>\u9501\uff0c\u6b64\u65f6\uff0c\u7ebf\u7a0b\u6267\u884c<code>while<\/code>\u6761\u4ef6\u5224\u65ad\uff0c\u5982\u679c\u6761\u4ef6\u6210\u7acb\uff08\u961f\u5217\u4e3a\u7a7a\uff09\uff0c\u7ebf\u7a0b\u5c06\u6267\u884c<code>this.wait()<\/code>\uff0c\u8fdb\u5165\u7b49\u5f85\u72b6\u6001\u3002<\/p>\n\n\n\n<p>\u8fd9\u91cc\u7684\u5173\u952e\u662f\uff1a<code>wait()<\/code>\u65b9\u6cd5\u5fc5\u987b\u5728\u5f53\u524d\u83b7\u53d6\u7684\u9501\u5bf9\u8c61\u4e0a\u8c03\u7528\uff0c\u8fd9\u91cc\u83b7\u53d6\u7684\u662f<code>this<\/code>\u9501\uff0c\u56e0\u6b64\u8c03\u7528<code>this.wait()<\/code>\u3002<\/p>\n\n\n\n<p>\u8c03\u7528<code>wait()<\/code>\u65b9\u6cd5\u540e\uff0c\u7ebf\u7a0b\u8fdb\u5165\u7b49\u5f85\u72b6\u6001\uff0c<code>wait()<\/code>\u65b9\u6cd5\u4e0d\u4f1a\u8fd4\u56de\uff0c\u76f4\u5230\u5c06\u6765\u67d0\u4e2a\u65f6\u523b\uff0c\u7ebf\u7a0b\u4ece\u7b49\u5f85\u72b6\u6001\u88ab\u5176\u4ed6\u7ebf\u7a0b\u5524\u9192\u540e\uff0c<code>wait()<\/code>\u65b9\u6cd5\u624d\u4f1a\u8fd4\u56de\uff0c\u7136\u540e\uff0c\u7ee7\u7eed\u6267\u884c\u4e0b\u4e00\u6761\u8bed\u53e5\u3002<\/p>\n\n\n\n<p>\u6709\u4e9b\u4ed4\u7ec6\u7684\u7ae5\u978b\u4f1a\u6307\u51fa\uff1a\u5373\u4f7f\u7ebf\u7a0b\u5728<code>getTask()<\/code>\u5185\u90e8\u7b49\u5f85\uff0c\u5176\u4ed6\u7ebf\u7a0b\u5982\u679c\u62ff\u4e0d\u5230<code>this<\/code>\u9501\uff0c\u7167\u6837\u65e0\u6cd5\u6267\u884c<code>addTask()<\/code>\uff0c\u80bf\u4e48\u529e\uff1f<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u95ee\u9898\u7684\u5173\u952e\u5c31\u5728\u4e8e<code>wait()<\/code>\u65b9\u6cd5\u7684\u6267\u884c\u673a\u5236\u975e\u5e38\u590d\u6742\u3002\u9996\u5148\uff0c\u5b83\u4e0d\u662f\u4e00\u4e2a\u666e\u901a\u7684Java\u65b9\u6cd5\uff0c\u800c\u662f\u5b9a\u4e49\u5728<code>Object<\/code>\u7c7b\u7684\u4e00\u4e2a<code>native<\/code>\u65b9\u6cd5\uff0c\u4e5f\u5c31\u662f\u7531JVM\u7684C\u4ee3\u7801\u5b9e\u73b0\u7684\u3002\u5176\u6b21\uff0c\u5fc5\u987b\u5728<code>synchronized<\/code>\u5757\u4e2d\u624d\u80fd\u8c03\u7528<code>wait()<\/code>\u65b9\u6cd5\uff0c\u56e0\u4e3a<code>wait()<\/code>\u65b9\u6cd5\u8c03\u7528\u65f6\uff0c\u4f1a<em>\u91ca\u653e<\/em>\u7ebf\u7a0b\u83b7\u5f97\u7684\u9501\uff0c<code>wait()<\/code>\u65b9\u6cd5\u8fd4\u56de\u65f6\uff0c\u7ebf\u7a0b\u53c8\u4f1a\u91cd\u65b0\u8bd5\u56fe\u83b7\u5f97\u9501\u3002<\/p>\n\n\n\n<p>\u56e0\u6b64\uff0c\u53ea\u80fd\u5728\u9501\u5bf9\u8c61\u4e0a\u8c03\u7528<code>wait()<\/code>\u65b9\u6cd5\u3002\u56e0\u4e3a\u5728<code>getTask()<\/code>\u4e2d\uff0c\u6211\u4eec\u83b7\u5f97\u4e86<code>this<\/code>\u9501\uff0c\u56e0\u6b64\uff0c\u53ea\u80fd\u5728<code>this<\/code>\u5bf9\u8c61\u4e0a\u8c03\u7528<code>wait()<\/code>\u65b9\u6cd5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public synchronized String getTask() {\n    while (queue.isEmpty()) {\n        \/\/ \u91ca\u653ethis\u9501:\n        this.wait();\n        \/\/ \u91cd\u65b0\u83b7\u53d6this\u9501\n    }\n    return queue.remove();\n}\n<\/code><\/pre>\n\n\n\n<p>\u5f53\u4e00\u4e2a\u7ebf\u7a0b\u5728<code>this.wait()<\/code>\u7b49\u5f85\u65f6\uff0c\u5b83\u5c31\u4f1a\u91ca\u653e<code>this<\/code>\u9501\uff0c\u4ece\u800c\u4f7f\u5f97\u5176\u4ed6\u7ebf\u7a0b\u80fd\u591f\u5728<code>addTask()<\/code>\u65b9\u6cd5\u83b7\u5f97<code>this<\/code>\u9501\u3002<\/p>\n\n\n\n<p>\u73b0\u5728\u6211\u4eec\u9762\u4e34\u7b2c\u4e8c\u4e2a\u95ee\u9898\uff1a\u5982\u4f55\u8ba9\u7b49\u5f85\u7684\u7ebf\u7a0b\u88ab\u91cd\u65b0\u5524\u9192\uff0c\u7136\u540e\u4ece<code>wait()<\/code>\u65b9\u6cd5\u8fd4\u56de\uff1f\u7b54\u6848\u662f\u5728\u76f8\u540c\u7684\u9501\u5bf9\u8c61\u4e0a\u8c03\u7528<code>notify()<\/code>\u65b9\u6cd5\u3002\u6211\u4eec\u4fee\u6539<code>addTask()<\/code>\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public synchronized void addTask(String s) {\n    this.queue.add(s);\n    this.notify(); \/\/ \u5524\u9192\u5728this\u9501\u7b49\u5f85\u7684\u7ebf\u7a0b\n}\n<\/code><\/pre>\n\n\n\n<p>\u6ce8\u610f\u5230\u5728\u5f80\u961f\u5217\u4e2d\u6dfb\u52a0\u4e86\u4efb\u52a1\u540e\uff0c\u7ebf\u7a0b\u7acb\u523b\u5bf9<code>this<\/code>\u9501\u5bf9\u8c61\u8c03\u7528<code>notify()<\/code>\u65b9\u6cd5\uff0c\u8fd9\u4e2a\u65b9\u6cd5\u4f1a\u5524\u9192\u4e00\u4e2a\u6b63\u5728<code>this<\/code>\u9501\u7b49\u5f85\u7684\u7ebf\u7a0b\uff08\u5c31\u662f\u5728<code>getTask()<\/code>\u4e2d\u4f4d\u4e8e<code>this.wait()<\/code>\u7684\u7ebf\u7a0b\uff09\uff0c\u4ece\u800c\u4f7f\u5f97\u7b49\u5f85\u7ebf\u7a0b\u4ece<code>this.wait()<\/code>\u65b9\u6cd5\u8fd4\u56de\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u5b8c\u6574\u7684\u4f8b\u5b50\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>import java.util.*;\n\npublic class Main {\n    public static void main(String&#91;] args) throws InterruptedException {\n        var q = new TaskQueue();\n        var ts = new ArrayList&lt;Thread&gt;();\n        for (int i=0; i&lt;5; i++) {\n            var t = new Thread() {\n                public void run() {\n                    \/\/ \u6267\u884ctask:\n                    while (true) {\n                        try {\n                            String s = q.getTask();\n                            System.out.println(\"execute task: \" + s);\n                        } catch (InterruptedException e) {\n                            return;\n                        }\n                    }\n                }\n            };\n            t.start();\n            ts.add(t);\n        }\n        var add = new Thread(() -&gt; {\n            for (int i=0; i&lt;10; i++) {\n                \/\/ \u653e\u5165task:\n                String s = \"t-\" + Math.random();\n                System.out.println(\"add task: \" + s);\n                q.addTask(s);\n                try { Thread.sleep(100); } catch(InterruptedException e) {}\n            }\n        });\n        add.start();\n        add.join();\n        Thread.sleep(100);\n        for (var t : ts) {\n            t.interrupt();\n        }\n    }\n}\n\nclass TaskQueue {\n    Queue&lt;String&gt; queue = new LinkedList&lt;&gt;();\n\n    public synchronized void addTask(String s) {\n        this.queue.add(s);\n        this.notifyAll();\n    }\n\n    public synchronized String getTask() throws InterruptedException {\n        while (queue.isEmpty()) {\n            this.wait();\n        }\n        return queue.remove();\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u91cd\u70b9\u5173\u6ce8<code>addTask()<\/code>\u65b9\u6cd5\uff0c\u5185\u90e8\u8c03\u7528\u4e86<code>this.notifyAll()<\/code>\u800c\u4e0d\u662f<code>this.notify()<\/code>\uff0c\u4f7f\u7528<code>notifyAll()<\/code>\u5c06\u5524\u9192\u6240\u6709\u5f53\u524d\u6b63\u5728<code>this<\/code>\u9501\u7b49\u5f85\u7684\u7ebf\u7a0b\uff0c\u800c<code>notify()<\/code>\u53ea\u4f1a\u5524\u9192\u5176\u4e2d\u4e00\u4e2a\uff08\u5177\u4f53\u54ea\u4e2a\u4f9d\u8d56\u64cd\u4f5c\u7cfb\u7edf\uff0c\u6709\u4e00\u5b9a\u7684\u968f\u673a\u6027\uff09\u3002\u8fd9\u662f\u56e0\u4e3a\u53ef\u80fd\u6709\u591a\u4e2a\u7ebf\u7a0b\u6b63\u5728<code>getTask()<\/code>\u65b9\u6cd5\u5185\u90e8\u7684<code>wait()<\/code>\u4e2d\u7b49\u5f85\uff0c\u4f7f\u7528<code>notifyAll()<\/code>\u5c06\u4e00\u6b21\u6027\u5168\u90e8\u5524\u9192\u3002\u901a\u5e38\u6765\u8bf4\uff0c<code>notifyAll()<\/code>\u66f4\u5b89\u5168\u3002\u6709\u4e9b\u65f6\u5019\uff0c\u5982\u679c\u6211\u4eec\u7684\u4ee3\u7801\u903b\u8f91\u8003\u8651\u4e0d\u5468\uff0c\u7528<code>notify()<\/code>\u4f1a\u5bfc\u81f4\u53ea\u5524\u9192\u4e86\u4e00\u4e2a\u7ebf\u7a0b\uff0c\u800c\u5176\u4ed6\u7ebf\u7a0b\u53ef\u80fd\u6c38\u8fdc\u7b49\u5f85\u4e0b\u53bb\u9192\u4e0d\u8fc7\u6765\u4e86\u3002<\/p>\n\n\n\n<p>\u4f46\u662f\uff0c\u6ce8\u610f\u5230<code>wait()<\/code>\u65b9\u6cd5\u8fd4\u56de\u65f6\u9700\u8981<em>\u91cd\u65b0<\/em>\u83b7\u5f97<code>this<\/code>\u9501\u3002\u5047\u8bbe\u5f53\u524d\u67093\u4e2a\u7ebf\u7a0b\u88ab\u5524\u9192\uff0c\u5524\u9192\u540e\uff0c\u9996\u5148\u8981\u7b49\u5f85\u6267\u884c<code>addTask()<\/code>\u7684\u7ebf\u7a0b\u7ed3\u675f\u6b64\u65b9\u6cd5\u540e\uff0c\u624d\u80fd\u91ca\u653e<code>this<\/code>\u9501\uff0c\u968f\u540e\uff0c\u8fd93\u4e2a\u7ebf\u7a0b\u4e2d\u53ea\u80fd\u6709\u4e00\u4e2a\u83b7\u53d6\u5230<code>this<\/code>\u9501\uff0c\u5269\u4e0b\u4e24\u4e2a\u5c06\u7ee7\u7eed\u7b49\u5f85\u3002<\/p>\n\n\n\n<p>\u518d\u6ce8\u610f\u5230\u6211\u4eec\u5728<code>while()<\/code>\u5faa\u73af\u4e2d\u8c03\u7528<code>wait()<\/code>\uff0c\u800c\u4e0d\u662f<code>if<\/code>\u8bed\u53e5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public synchronized String getTask() throws InterruptedException {\n    if (queue.isEmpty()) {\n        this.wait();\n    }\n    return queue.remove();\n}\n<\/code><\/pre>\n\n\n\n<p>\u8fd9\u79cd\u5199\u6cd5\u5b9e\u9645\u4e0a\u662f\u9519\u8bef\u7684\uff0c\u56e0\u4e3a\u7ebf\u7a0b\u88ab\u5524\u9192\u65f6\uff0c\u9700\u8981\u518d\u6b21\u83b7\u53d6<code>this<\/code>\u9501\u3002\u591a\u4e2a\u7ebf\u7a0b\u88ab\u5524\u9192\u540e\uff0c\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u80fd\u83b7\u53d6<code>this<\/code>\u9501\uff0c\u6b64\u523b\uff0c\u8be5\u7ebf\u7a0b\u6267\u884c<code>queue.remove()<\/code>\u53ef\u4ee5\u83b7\u53d6\u5230\u961f\u5217\u7684\u5143\u7d20\uff0c\u7136\u800c\uff0c\u5269\u4e0b\u7684\u7ebf\u7a0b\u5982\u679c\u83b7\u53d6<code>this<\/code>\u9501\u540e\u6267\u884c<code>queue.remove()<\/code>\uff0c\u6b64\u523b\u961f\u5217\u53ef\u80fd\u5df2\u7ecf\u6ca1\u6709\u4efb\u4f55\u5143\u7d20\u4e86\uff0c\u6240\u4ee5\uff0c\u8981\u59cb\u7ec8\u5728<code>while<\/code>\u5faa\u73af\u4e2d<code>wait()<\/code>\uff0c\u5e76\u4e14\u6bcf\u6b21\u88ab\u5524\u9192\u540e\u62ff\u5230<code>this<\/code>\u9501\u5c31\u5fc5\u987b\u518d\u6b21\u5224\u65ad\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>while (queue.isEmpty()) {\n    this.wait();\n}<\/code><\/pre>\n\n\n\n<p>\u4eceJava 5\u5f00\u59cb\uff0c\u5f15\u5165\u4e86\u4e00\u4e2a\u9ad8\u7ea7\u7684\u5904\u7406\u5e76\u53d1\u7684<code>java.util.concurrent<\/code>\u5305\uff0c\u5b83\u63d0\u4f9b\u4e86\u5927\u91cf\u66f4\u9ad8\u7ea7\u7684\u5e76\u53d1\u529f\u80fd\uff0c\u80fd\u5927\u5927\u7b80\u5316\u591a\u7ebf\u7a0b\u7a0b\u5e8f\u7684\u7f16\u5199\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u77e5\u9053Java\u8bed\u8a00\u76f4\u63a5\u63d0\u4f9b\u4e86<code>synchronized<\/code>\u5173\u952e\u5b57\u7528\u4e8e\u52a0\u9501\uff0c\u4f46\u8fd9\u79cd\u9501\u4e00\u662f\u5f88\u91cd\uff0c\u4e8c\u662f\u83b7\u53d6\u65f6\u5fc5\u987b\u4e00\u76f4\u7b49\u5f85\uff0c\u6ca1\u6709\u989d\u5916\u7684\u5c1d\u8bd5\u673a\u5236\u3002<\/p>\n\n\n\n<p><code>java.util.concurrent.locks<\/code>\u5305\u63d0\u4f9b\u7684<code>ReentrantLock<\/code>\u7528\u4e8e\u66ff\u4ee3<code>synchronized<\/code>\u52a0\u9501\uff0c\u6211\u4eec\u6765\u770b\u4e00\u4e0b\u4f20\u7edf\u7684<code>synchronized<\/code>\u4ee3\u7801\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Counter {\n    private int count;\n\n    public void add(int n) {\n        synchronized(this) {\n            count += n;\n        }\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u5982\u679c\u7528<code>ReentrantLock<\/code>\u66ff\u4ee3\uff0c\u53ef\u4ee5\u628a\u4ee3\u7801\u6539\u9020\u4e3a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Counter {\n    private final Lock lock = new ReentrantLock();\n    private int count;\n\n    public void add(int n) {\n        lock.lock();\n        try {\n            count += n;\n        } finally {\n            lock.unlock();\n        }\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u56e0\u4e3a<code>synchronized<\/code>\u662fJava\u8bed\u8a00\u5c42\u9762\u63d0\u4f9b\u7684\u8bed\u6cd5\uff0c\u6240\u4ee5\u6211\u4eec\u4e0d\u9700\u8981\u8003\u8651\u5f02\u5e38\uff0c\u800c<code>ReentrantLock<\/code>\u662fJava\u4ee3\u7801\u5b9e\u73b0\u7684\u9501\uff0c\u6211\u4eec\u5c31\u5fc5\u987b\u5148\u83b7\u53d6\u9501\uff0c\u7136\u540e\u5728<code>finally<\/code>\u4e2d\u6b63\u786e\u91ca\u653e\u9501\u3002<\/p>\n\n\n\n<p>\u987e\u540d\u601d\u4e49\uff0c<code>ReentrantLock<\/code>\u662f\u53ef\u91cd\u5165\u9501\uff0c\u5b83\u548c<code>synchronized<\/code>\u4e00\u6837\uff0c\u4e00\u4e2a\u7ebf\u7a0b\u53ef\u4ee5\u591a\u6b21\u83b7\u53d6\u540c\u4e00\u4e2a\u9501\u3002<\/p>\n\n\n\n<p>\u548c<code>synchronized<\/code>\u4e0d\u540c\u7684\u662f\uff0c<code>ReentrantLock<\/code>\u53ef\u4ee5\u5c1d\u8bd5\u83b7\u53d6\u9501\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if (lock.tryLock(1, TimeUnit.SECONDS)) {\n    try {\n        ...\n    } finally {\n        lock.unlock();\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u4e0a\u8ff0\u4ee3\u7801\u5728\u5c1d\u8bd5\u83b7\u53d6\u9501\u7684\u65f6\u5019\uff0c\u6700\u591a\u7b49\u5f851\u79d2\u3002\u5982\u679c1\u79d2\u540e\u4ecd\u672a\u83b7\u53d6\u5230\u9501\uff0c<code>tryLock()<\/code>\u8fd4\u56de<code>false<\/code>\uff0c\u7a0b\u5e8f\u5c31\u53ef\u4ee5\u505a\u4e00\u4e9b\u989d\u5916\u5904\u7406\uff0c\u800c\u4e0d\u662f\u65e0\u9650\u7b49\u5f85\u4e0b\u53bb\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\uff0c\u4f7f\u7528<code>ReentrantLock<\/code>\u6bd4\u76f4\u63a5\u4f7f\u7528<code>synchronized<\/code>\u66f4\u5b89\u5168\uff0c\u7ebf\u7a0b\u5728<code>tryLock()<\/code>\u5931\u8d25\u7684\u65f6\u5019\u4e0d\u4f1a\u5bfc\u81f4\u6b7b\u9501\u3002<\/p>\n\n\n\n<p>\u4f7f\u7528<code>ReentrantLock<\/code>\u6bd4\u76f4\u63a5\u4f7f\u7528<code>synchronized<\/code>\u66f4\u5b89\u5168\uff0c\u53ef\u4ee5\u66ff\u4ee3<code>synchronized<\/code>\u8fdb\u884c\u7ebf\u7a0b\u540c\u6b65\u3002<\/p>\n\n\n\n<p>\u4f46\u662f\uff0c<code>synchronized<\/code>\u53ef\u4ee5\u914d\u5408<code>wait<\/code>\u548c<code>notify<\/code>\u5b9e\u73b0\u7ebf\u7a0b\u5728\u6761\u4ef6\u4e0d\u6ee1\u8db3\u65f6\u7b49\u5f85\uff0c\u6761\u4ef6\u6ee1\u8db3\u65f6\u5524\u9192\uff0c\u7528<code>ReentrantLock<\/code>\u6211\u4eec\u600e\u4e48\u7f16\u5199<code>wait<\/code>\u548c<code>notify<\/code>\u7684\u529f\u80fd\u5462\uff1f<\/p>\n\n\n\n<p>\u7b54\u6848\u662f\u4f7f\u7528<code>Condition<\/code>\u5bf9\u8c61\u6765\u5b9e\u73b0<code>wait<\/code>\u548c<code>notify<\/code>\u7684\u529f\u80fd\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u4ecd\u7136\u4ee5<code>TaskQueue<\/code>\u4e3a\u4f8b\uff0c\u628a\u524d\u9762\u7528<code>synchronized<\/code>\u5b9e\u73b0\u7684\u529f\u80fd\u901a\u8fc7<code>ReentrantLock<\/code>\u548c<code>Condition<\/code>\u6765\u5b9e\u73b0\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>class TaskQueue {\n    private final Lock lock = new ReentrantLock();\n    private final Condition condition = lock.newCondition();\n    private Queue&lt;String&gt; queue = new LinkedList&lt;&gt;();\n\n    public void addTask(String s) {\n        lock.lock();\n        try {\n            queue.add(s);\n            condition.signalAll();\n        } finally {\n            lock.unlock();\n        }\n    }\n\n    public String getTask() {\n        lock.lock();\n        try {\n            while (queue.isEmpty()) {\n                condition.await();\n            }\n            return queue.remove();\n        } finally {\n            lock.unlock();\n        }\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u53ef\u89c1\uff0c\u4f7f\u7528<code>Condition<\/code>\u65f6\uff0c\u5f15\u7528\u7684<code>Condition<\/code>\u5bf9\u8c61\u5fc5\u987b\u4ece<code>Lock<\/code>\u5b9e\u4f8b\u7684<code>newCondition()<\/code>\u8fd4\u56de\uff0c\u8fd9\u6837\u624d\u80fd\u83b7\u5f97\u4e00\u4e2a\u7ed1\u5b9a\u4e86<code>Lock<\/code>\u5b9e\u4f8b\u7684<code>Condition<\/code>\u5b9e\u4f8b\u3002<\/p>\n\n\n\n<p><code>Condition<\/code>\u63d0\u4f9b\u7684<code>await()<\/code>\u3001<code>signal()<\/code>\u3001<code>signalAll()<\/code>\u539f\u7406\u548c<code>synchronized<\/code>\u9501\u5bf9\u8c61\u7684<code>wait()<\/code>\u3001<code>notify()<\/code>\u3001<code>notifyAll()<\/code>\u662f\u4e00\u81f4\u7684\uff0c\u5e76\u4e14\u5176\u884c\u4e3a\u4e5f\u662f\u4e00\u6837\u7684\uff1a<\/p>\n\n\n\n<ul>\n<li><code>await()<\/code>\u4f1a\u91ca\u653e\u5f53\u524d\u9501\uff0c\u8fdb\u5165\u7b49\u5f85\u72b6\u6001\uff1b<\/li>\n\n\n\n<li><code>signal()<\/code>\u4f1a\u5524\u9192\u67d0\u4e2a\u7b49\u5f85\u7ebf\u7a0b\uff1b<\/li>\n\n\n\n<li><code>signalAll()<\/code>\u4f1a\u5524\u9192\u6240\u6709\u7b49\u5f85\u7ebf\u7a0b\uff1b<\/li>\n\n\n\n<li>\u5524\u9192\u7ebf\u7a0b\u4ece<code>await()<\/code>\u8fd4\u56de\u540e\u9700\u8981\u91cd\u65b0\u83b7\u5f97\u9501\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u6b64\u5916\uff0c\u548c<code>tryLock()<\/code>\u7c7b\u4f3c\uff0c<code>await()<\/code>\u53ef\u4ee5\u5728\u7b49\u5f85\u6307\u5b9a\u65f6\u95f4\u540e\uff0c\u5982\u679c\u8fd8\u6ca1\u6709\u88ab\u5176\u4ed6\u7ebf\u7a0b\u901a\u8fc7<code>signal()<\/code>\u6216<code>signalAll()<\/code>\u5524\u9192\uff0c\u53ef\u4ee5\u81ea\u5df1\u9192\u6765\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if (condition.await(1, TimeUnit.SECOND)) {\n    \/\/ \u88ab\u5176\u4ed6\u7ebf\u7a0b\u5524\u9192\n} else {\n    \/\/ \u6307\u5b9a\u65f6\u95f4\u5185\u6ca1\u6709\u88ab\u5176\u4ed6\u7ebf\u7a0b\u5524\u9192\n}\n<\/code><\/pre>\n\n\n\n<p>\u53ef\u89c1\uff0c\u4f7f\u7528<code>Condition<\/code>\u914d\u5408<code>Lock<\/code>\uff0c\u6211\u4eec\u53ef\u4ee5\u5b9e\u73b0\u66f4\u7075\u6d3b\u7684\u7ebf\u7a0b\u540c\u6b65\u3002<\/p>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-pale-pink-color\">\u7b2c\u56db\u6b65\uff1a\u591a\u7ebf\u7a0b\u6548\u7387<\/mark><\/p>\n\n\n\n<p>\u524d\u9762\u8bb2\u5230\u7684<code>ReentrantLock<\/code>\u4fdd\u8bc1\u4e86\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u53ef\u4ee5\u6267\u884c\u4e34\u754c\u533a\u4ee3\u7801\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Counter {\n    private final Lock lock = new ReentrantLock();\n    private int&#91;] counts = new int&#91;10];\n\n    public void inc(int index) {\n        lock.lock();\n        try {\n            counts&#91;index] += 1;\n        } finally {\n            lock.unlock();\n        }\n    }\n\n    public int&#91;] get() {\n        lock.lock();\n        try {\n            return Arrays.copyOf(counts, counts.length);\n        } finally {\n            lock.unlock();\n        }\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u4f46\u662f\u6709\u4e9b\u65f6\u5019\uff0c\u8fd9\u79cd\u4fdd\u62a4\u6709\u70b9\u8fc7\u5934\u3002\u56e0\u4e3a\u6211\u4eec\u53d1\u73b0\uff0c\u4efb\u4f55\u65f6\u523b\uff0c\u53ea\u5141\u8bb8\u4e00\u4e2a\u7ebf\u7a0b\u4fee\u6539\uff0c\u4e5f\u5c31\u662f\u8c03\u7528<code>inc()<\/code>\u65b9\u6cd5\u662f\u5fc5\u987b\u83b7\u53d6\u9501\uff0c\u4f46\u662f\uff0c<code>get()<\/code>\u65b9\u6cd5\u53ea\u8bfb\u53d6\u6570\u636e\uff0c\u4e0d\u4fee\u6539\u6570\u636e\uff0c\u5b83\u5b9e\u9645\u4e0a\u5141\u8bb8\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8c03\u7528\u3002<\/p>\n\n\n\n<p>\u5b9e\u9645\u4e0a\u6211\u4eec\u60f3\u8981\u7684\u662f\uff1a\u5141\u8bb8\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8bfb\uff0c\u4f46\u53ea\u8981\u6709\u4e00\u4e2a\u7ebf\u7a0b\u5728\u5199\uff0c\u5176\u4ed6\u7ebf\u7a0b\u5c31\u5fc5\u987b\u7b49\u5f85\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th><\/th><th>\u8bfb<\/th><th>\u5199<\/th><\/tr><\/thead><tbody><tr><td>\u8bfb<\/td><td>\u5141\u8bb8<\/td><td>\u4e0d\u5141\u8bb8<\/td><\/tr><tr><td>\u5199<\/td><td>\u4e0d\u5141\u8bb8<\/td><td>\u4e0d\u5141\u8bb8<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u4f7f\u7528<code>ReadWriteLock<\/code>\u53ef\u4ee5\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u5b83\u4fdd\u8bc1\uff1a<\/p>\n\n\n\n<ul>\n<li>\u53ea\u5141\u8bb8\u4e00\u4e2a\u7ebf\u7a0b\u5199\u5165\uff08\u5176\u4ed6\u7ebf\u7a0b\u65e2\u4e0d\u80fd\u5199\u5165\u4e5f\u4e0d\u80fd\u8bfb\u53d6\uff09\uff1b<\/li>\n\n\n\n<li>\u6ca1\u6709\u5199\u5165\u65f6\uff0c\u591a\u4e2a\u7ebf\u7a0b\u5141\u8bb8\u540c\u65f6\u8bfb\uff08\u63d0\u9ad8\u6027\u80fd\uff09\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u7528<code>ReadWriteLock<\/code>\u5b9e\u73b0\u8fd9\u4e2a\u529f\u80fd\u5341\u5206\u5bb9\u6613\u3002\u6211\u4eec\u9700\u8981\u521b\u5efa\u4e00\u4e2a<code>ReadWriteLock<\/code>\u5b9e\u4f8b\uff0c\u7136\u540e\u5206\u522b\u83b7\u53d6\u8bfb\u9501\u548c\u5199\u9501\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Counter {\n    private final ReadWriteLock rwlock = new ReentrantReadWriteLock();\n    \/\/ \u6ce8\u610f: \u4e00\u5bf9\u8bfb\u9501\u548c\u5199\u9501\u5fc5\u987b\u4ece\u540c\u4e00\u4e2arwlock\u83b7\u53d6:\n    private final Lock rlock = rwlock.readLock();\n    private final Lock wlock = rwlock.writeLock();\n    private int&#91;] counts = new int&#91;10];\n\n    public void inc(int index) {\n        wlock.lock(); \/\/ \u52a0\u5199\u9501\n        try {\n            counts&#91;index] += 1;\n        } finally {\n            wlock.unlock(); \/\/ \u91ca\u653e\u5199\u9501\n        }\n    }\n\n    public int&#91;] get() {\n        rlock.lock(); \/\/ \u52a0\u8bfb\u9501\n        try {\n            return Arrays.copyOf(counts, counts.length);\n        } finally {\n            rlock.unlock(); \/\/ \u91ca\u653e\u8bfb\u9501\n        }\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u628a\u8bfb\u5199\u64cd\u4f5c\u5206\u522b\u7528\u8bfb\u9501\u548c\u5199\u9501\u6765\u52a0\u9501\uff0c\u5728\u8bfb\u53d6\u65f6\uff0c\u591a\u4e2a\u7ebf\u7a0b\u53ef\u4ee5\u540c\u65f6\u83b7\u5f97\u8bfb\u9501\uff0c\u8fd9\u6837\u5c31\u5927\u5927\u63d0\u9ad8\u4e86\u5e76\u53d1\u8bfb\u7684\u6267\u884c\u6548\u7387\u3002<\/p>\n\n\n\n<p>\u4f7f\u7528<code>ReadWriteLock<\/code>\u65f6\uff0c\u9002\u7528\u6761\u4ef6\u662f\u540c\u4e00\u4e2a\u6570\u636e\uff0c\u6709\u5927\u91cf\u7ebf\u7a0b\u8bfb\u53d6\uff0c\u4f46\u4ec5\u6709\u5c11\u6570\u7ebf\u7a0b\u4fee\u6539\u3002<\/p>\n\n\n\n<p>\u4f8b\u5982\uff0c\u4e00\u4e2a\u8bba\u575b\u7684\u5e16\u5b50\uff0c\u56de\u590d\u53ef\u4ee5\u770b\u505a\u5199\u5165\u64cd\u4f5c\uff0c\u5b83\u662f\u4e0d\u9891\u7e41\u7684\uff0c\u4f46\u662f\uff0c\u6d4f\u89c8\u53ef\u4ee5\u770b\u505a\u8bfb\u53d6\u64cd\u4f5c\uff0c\u662f\u975e\u5e38\u9891\u7e41\u7684\uff0c\u8fd9\u79cd\u60c5\u51b5\u5c31\u53ef\u4ee5\u4f7f\u7528<code>ReadWriteLock<\/code>\u3002<\/p>\n\n\n\n<p>\u524d\u9762\u4ecb\u7ecd\u7684<code>ReadWriteLock<\/code>\u53ef\u4ee5\u89e3\u51b3\u591a\u7ebf\u7a0b\u540c\u65f6\u8bfb\uff0c\u4f46\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u80fd\u5199\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u6211\u4eec\u6df1\u5165\u5206\u6790<code>ReadWriteLock<\/code>\uff0c\u4f1a\u53d1\u73b0\u5b83\u6709\u4e2a\u6f5c\u5728\u7684\u95ee\u9898\uff1a\u5982\u679c\u6709\u7ebf\u7a0b\u6b63\u5728\u8bfb\uff0c\u5199\u7ebf\u7a0b\u9700\u8981\u7b49\u5f85\u8bfb\u7ebf\u7a0b\u91ca\u653e\u9501\u540e\u624d\u80fd\u83b7\u53d6\u5199\u9501\uff0c\u5373\u8bfb\u7684\u8fc7\u7a0b\u4e2d\u4e0d\u5141\u8bb8\u5199\uff0c\u8fd9\u662f\u4e00\u79cd\u60b2\u89c2\u7684\u8bfb\u9501\u3002<\/p>\n\n\n\n<p>\u8981\u8fdb\u4e00\u6b65\u63d0\u5347\u5e76\u53d1\u6267\u884c\u6548\u7387\uff0cJava 8\u5f15\u5165\u4e86\u65b0\u7684\u8bfb\u5199\u9501\uff1a<code>StampedLock<\/code>\u3002<\/p>\n\n\n\n<p><code>StampedLock<\/code>\u548c<code>ReadWriteLock<\/code>\u76f8\u6bd4\uff0c\u6539\u8fdb\u4e4b\u5904\u5728\u4e8e\uff1a\u8bfb\u7684\u8fc7\u7a0b\u4e2d\u4e5f\u5141\u8bb8\u83b7\u53d6\u5199\u9501\u540e\u5199\u5165\uff01\u8fd9\u6837\u4e00\u6765\uff0c\u6211\u4eec\u8bfb\u7684\u6570\u636e\u5c31\u53ef\u80fd\u4e0d\u4e00\u81f4\uff0c\u6240\u4ee5\uff0c\u9700\u8981\u4e00\u70b9\u989d\u5916\u7684\u4ee3\u7801\u6765\u5224\u65ad\u8bfb\u7684\u8fc7\u7a0b\u4e2d\u662f\u5426\u6709\u5199\u5165\uff0c\u8fd9\u79cd\u8bfb\u9501\u662f\u4e00\u79cd\u4e50\u89c2\u9501\u3002<\/p>\n\n\n\n<p>\u4e50\u89c2\u9501\u7684\u610f\u601d\u5c31\u662f\u4e50\u89c2\u5730\u4f30\u8ba1\u8bfb\u7684\u8fc7\u7a0b\u4e2d\u5927\u6982\u7387\u4e0d\u4f1a\u6709\u5199\u5165\uff0c\u56e0\u6b64\u88ab\u79f0\u4e3a\u4e50\u89c2\u9501\u3002\u53cd\u8fc7\u6765\uff0c\u60b2\u89c2\u9501\u5219\u662f\u8bfb\u7684\u8fc7\u7a0b\u4e2d\u62d2\u7edd\u6709\u5199\u5165\uff0c\u4e5f\u5c31\u662f\u5199\u5165\u5fc5\u987b\u7b49\u5f85\u3002\u663e\u7136\u4e50\u89c2\u9501\u7684\u5e76\u53d1\u6548\u7387\u66f4\u9ad8\uff0c\u4f46\u4e00\u65e6\u6709\u5c0f\u6982\u7387\u7684\u5199\u5165\u5bfc\u81f4\u8bfb\u53d6\u7684\u6570\u636e\u4e0d\u4e00\u81f4\uff0c\u9700\u8981\u80fd\u68c0\u6d4b\u51fa\u6765\uff0c\u518d\u8bfb\u4e00\u904d\u5c31\u884c\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u6765\u770b\u4f8b\u5b50\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class Point {\n    private final StampedLock stampedLock = new StampedLock();\n\n    private double x;\n    private double y;\n\n    public void move(double deltaX, double deltaY) {\n        long stamp = stampedLock.writeLock(); \/\/ \u83b7\u53d6\u5199\u9501\n        try {\n            x += deltaX;\n            y += deltaY;\n        } finally {\n            stampedLock.unlockWrite(stamp); \/\/ \u91ca\u653e\u5199\u9501\n        }\n    }\n\n    public double distanceFromOrigin() {\n        long stamp = stampedLock.tryOptimisticRead(); \/\/ \u83b7\u5f97\u4e00\u4e2a\u4e50\u89c2\u8bfb\u9501\n        \/\/ \u6ce8\u610f\u4e0b\u9762\u4e24\u884c\u4ee3\u7801\u4e0d\u662f\u539f\u5b50\u64cd\u4f5c\n        \/\/ \u5047\u8bbex,y = (100,200)\n        double currentX = x;\n        \/\/ \u6b64\u5904\u5df2\u8bfb\u53d6\u5230x=100\uff0c\u4f46x,y\u53ef\u80fd\u88ab\u5199\u7ebf\u7a0b\u4fee\u6539\u4e3a(300,400)\n        double currentY = y;\n        \/\/ \u6b64\u5904\u5df2\u8bfb\u53d6\u5230y\uff0c\u5982\u679c\u6ca1\u6709\u5199\u5165\uff0c\u8bfb\u53d6\u662f\u6b63\u786e\u7684(100,200)\n        \/\/ \u5982\u679c\u6709\u5199\u5165\uff0c\u8bfb\u53d6\u662f\u9519\u8bef\u7684(100,400)\n        if (!stampedLock.validate(stamp)) { \/\/ \u68c0\u67e5\u4e50\u89c2\u8bfb\u9501\u540e\u662f\u5426\u6709\u5176\u4ed6\u5199\u9501\u53d1\u751f\n            stamp = stampedLock.readLock(); \/\/ \u83b7\u53d6\u4e00\u4e2a\u60b2\u89c2\u8bfb\u9501\n            try {\n                currentX = x;\n                currentY = y;\n            } finally {\n                stampedLock.unlockRead(stamp); \/\/ \u91ca\u653e\u60b2\u89c2\u8bfb\u9501\n            }\n        }\n        return Math.sqrt(currentX * currentX + currentY * currentY);\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u548c<code>ReadWriteLock<\/code>\u76f8\u6bd4\uff0c\u5199\u5165\u7684\u52a0\u9501\u662f\u5b8c\u5168\u4e00\u6837\u7684\uff0c\u4e0d\u540c\u7684\u662f\u8bfb\u53d6\u3002\u6ce8\u610f\u5230\u9996\u5148\u6211\u4eec\u901a\u8fc7<code>tryOptimisticRead()<\/code>\u83b7\u53d6\u4e00\u4e2a\u4e50\u89c2\u8bfb\u9501\uff0c\u5e76\u8fd4\u56de\u7248\u672c\u53f7\u3002\u63a5\u7740\u8fdb\u884c\u8bfb\u53d6\uff0c\u8bfb\u53d6\u5b8c\u6210\u540e\uff0c\u6211\u4eec\u901a\u8fc7<code>validate()<\/code>\u53bb\u9a8c\u8bc1\u7248\u672c\u53f7\uff0c\u5982\u679c\u5728\u8bfb\u53d6\u8fc7\u7a0b\u4e2d\u6ca1\u6709\u5199\u5165\uff0c\u7248\u672c\u53f7\u4e0d\u53d8\uff0c\u9a8c\u8bc1\u6210\u529f\uff0c\u6211\u4eec\u5c31\u53ef\u4ee5\u653e\u5fc3\u5730\u7ee7\u7eed\u540e\u7eed\u64cd\u4f5c\u3002\u5982\u679c\u5728\u8bfb\u53d6\u8fc7\u7a0b\u4e2d\u6709\u5199\u5165\uff0c\u7248\u672c\u53f7\u4f1a\u53d1\u751f\u53d8\u5316\uff0c\u9a8c\u8bc1\u5c06\u5931\u8d25\u3002\u5728\u5931\u8d25\u7684\u65f6\u5019\uff0c\u6211\u4eec\u518d\u901a\u8fc7\u83b7\u53d6\u60b2\u89c2\u8bfb\u9501\u518d\u6b21\u8bfb\u53d6\u3002\u7531\u4e8e\u5199\u5165\u7684\u6982\u7387\u4e0d\u9ad8\uff0c\u7a0b\u5e8f\u5728\u7edd\u5927\u90e8\u5206\u60c5\u51b5\u4e0b\u53ef\u4ee5\u901a\u8fc7\u4e50\u89c2\u8bfb\u9501\u83b7\u53d6\u6570\u636e\uff0c\u6781\u5c11\u6570\u60c5\u51b5\u4e0b\u4f7f\u7528\u60b2\u89c2\u8bfb\u9501\u83b7\u53d6\u6570\u636e\u3002<\/p>\n\n\n\n<p>\u53ef\u89c1\uff0c<code>StampedLock<\/code>\u628a\u8bfb\u9501\u7ec6\u5206\u4e3a\u4e50\u89c2\u8bfb\u548c\u60b2\u89c2\u8bfb\uff0c\u80fd\u8fdb\u4e00\u6b65\u63d0\u5347\u5e76\u53d1\u6548\u7387\u3002\u4f46\u8fd9\u4e5f\u662f\u6709\u4ee3\u4ef7\u7684\uff1a\u4e00\u662f\u4ee3\u7801\u66f4\u52a0\u590d\u6742\uff0c\u4e8c\u662f<code>StampedLock<\/code>\u662f\u4e0d\u53ef\u91cd\u5165\u9501\uff0c\u4e0d\u80fd\u5728\u4e00\u4e2a\u7ebf\u7a0b\u4e2d\u53cd\u590d\u83b7\u53d6\u540c\u4e00\u4e2a\u9501\u3002<\/p>\n\n\n\n<p><code>StampedLock<\/code>\u8fd8\u63d0\u4f9b\u4e86\u66f4\u590d\u6742\u7684\u5c06\u60b2\u89c2\u8bfb\u9501\u5347\u7ea7\u4e3a\u5199\u9501\u7684\u529f\u80fd\uff0c\u5b83\u4e3b\u8981\u4f7f\u7528\u5728if-then-update\u7684\u573a\u666f\uff1a\u5373\u5148\u8bfb\uff0c\u5982\u679c\u8bfb\u7684\u6570\u636e\u6ee1\u8db3\u6761\u4ef6\uff0c\u5c31\u8fd4\u56de\uff0c\u5982\u679c\u8bfb\u7684\u6570\u636e\u4e0d\u6ee1\u8db3\u6761\u4ef6\uff0c\u518d\u5c1d\u8bd5\u5199\u3002<\/p>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-pale-pink-color\">\u7b2c\u4e94\u6b65\uff1a\u591a\u7ebf\u7a0b\u7ebf\u7a0b\u6570\u9650\u5236<\/mark><\/p>\n\n\n\n<p>\u524d\u9762\u6211\u4eec\u8bb2\u4e86\u5404\u79cd\u9501\u7684\u5b9e\u73b0\uff0c\u672c\u8d28\u4e0a\u9501\u7684\u76ee\u7684\u662f\u4fdd\u62a4\u4e00\u79cd\u53d7\u9650\u8d44\u6e90\uff0c\u4fdd\u8bc1\u540c\u4e00\u65f6\u523b\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u80fd\u8bbf\u95ee\uff08ReentrantLock\uff09\uff0c\u6216\u8005\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u80fd\u5199\u5165\uff08ReadWriteLock\uff09\u3002<\/p>\n\n\n\n<p>\u8fd8\u6709\u4e00\u79cd\u53d7\u9650\u8d44\u6e90\uff0c\u5b83\u9700\u8981\u4fdd\u8bc1\u540c\u4e00\u65f6\u523b\u6700\u591a\u6709N\u4e2a\u7ebf\u7a0b\u80fd\u8bbf\u95ee\uff0c\u6bd4\u5982\u540c\u4e00\u65f6\u523b\u6700\u591a\u521b\u5efa100\u4e2a\u6570\u636e\u5e93\u8fde\u63a5\uff0c\u6700\u591a\u5141\u8bb810\u4e2a\u7528\u6237\u4e0b\u8f7d\u7b49\u3002<\/p>\n\n\n\n<p>\u8fd9\u79cd\u9650\u5236\u6570\u91cf\u7684\u9501\uff0c\u5982\u679c\u7528Lock\u6570\u7ec4\u6765\u5b9e\u73b0\uff0c\u5c31\u592a\u9ebb\u70e6\u4e86\u3002<\/p>\n\n\n\n<p>\u8fd9\u79cd\u60c5\u51b5\u5c31\u53ef\u4ee5\u4f7f\u7528<code>Semaphore<\/code>\uff0c\u4f8b\u5982\uff0c\u6700\u591a\u5141\u8bb83\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8bbf\u95ee\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class AccessLimitControl {\n    \/\/ \u4efb\u610f\u65f6\u523b\u4ec5\u5141\u8bb8\u6700\u591a3\u4e2a\u7ebf\u7a0b\u83b7\u53d6\u8bb8\u53ef:\n    final Semaphore semaphore = new Semaphore(3);\n\n    public String access() throws Exception {\n        \/\/ \u5982\u679c\u8d85\u8fc7\u4e86\u8bb8\u53ef\u6570\u91cf,\u5176\u4ed6\u7ebf\u7a0b\u5c06\u5728\u6b64\u7b49\u5f85:\n        semaphore.acquire();\n        try {\n            \/\/ TODO:\n            return UUID.randomUUID().toString();\n        } finally {\n            semaphore.release();\n        }\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u4f7f\u7528<code>Semaphore<\/code>\u5148\u8c03\u7528<code>acquire()<\/code>\u83b7\u53d6\uff0c\u7136\u540e\u901a\u8fc7<code>try ... finally<\/code>\u4fdd\u8bc1\u5728<code>finally<\/code>\u4e2d\u91ca\u653e\u3002<\/p>\n\n\n\n<p>\u8c03\u7528<code>acquire()<\/code>\u53ef\u80fd\u4f1a\u8fdb\u5165\u7b49\u5f85\uff0c\u76f4\u5230\u6ee1\u8db3\u6761\u4ef6\u4e3a\u6b62\u3002\u4e5f\u53ef\u4ee5\u4f7f\u7528<code>tryAcquire()<\/code>\u6307\u5b9a\u7b49\u5f85\u65f6\u95f4\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>if (semaphore.tryAcquire(3, TimeUnit.SECONDS)) {\n    \/\/ \u6307\u5b9a\u7b49\u5f85\u65f6\u95f43\u79d2\u5185\u83b7\u53d6\u5230\u8bb8\u53ef:\n    try {\n        \/\/ TODO:\n    } finally {\n        semaphore.release();\n    }\n}\n<\/code><\/pre>\n\n\n\n<p><code>Semaphore<\/code>\u672c\u8d28\u4e0a\u5c31\u662f\u4e00\u4e2a\u4fe1\u53f7\u8ba1\u6570\u5668\uff0c\u7528\u4e8e\u9650\u5236\u540c\u4e00\u65f6\u95f4\u7684\u6700\u5927\u8bbf\u95ee\u6570\u91cf\u3002<\/p>\n\n\n\n<p class=\"has-large-font-size\"><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-pale-pink-color\">\u7b2c\u516d\u6b65\uff1a\u591a\u7ebf\u7a0b\u5b9e\u7528\u7c7b\u548c\u539f\u5b50\u64cd\u4f5c<\/mark><\/p>\n\n\n\n<p>\u6211\u4eec\u5728\u524d\u9762\u5df2\u7ecf\u901a\u8fc7<code>ReentrantLock<\/code>\u548c<code>Condition<\/code>\u5b9e\u73b0\u4e86\u4e00\u4e2a<code>BlockingQueue<\/code>\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public class TaskQueue {\n    private final Lock lock = new ReentrantLock();\n    private final Condition condition = lock.newCondition();\n    private Queue&lt;String&gt; queue = new LinkedList&lt;&gt;();\n\n    public void addTask(String s) {\n        lock.lock();\n        try {\n            queue.add(s);\n            condition.signalAll();\n        } finally {\n            lock.unlock();\n        }\n    }\n\n    public String getTask() {\n        lock.lock();\n        try {\n            while (queue.isEmpty()) {\n                condition.await();\n            }\n            return queue.remove();\n        } finally {\n            lock.unlock();\n        }\n    }\n}\n<\/code><\/pre>\n\n\n\n<p><code>BlockingQueue<\/code>\u7684\u610f\u601d\u5c31\u662f\u8bf4\uff0c\u5f53\u4e00\u4e2a\u7ebf\u7a0b\u8c03\u7528\u8fd9\u4e2a<code>TaskQueue<\/code>\u7684<code>getTask()<\/code>\u65b9\u6cd5\u65f6\uff0c\u8be5\u65b9\u6cd5\u5185\u90e8\u53ef\u80fd\u4f1a\u8ba9\u7ebf\u7a0b\u53d8\u6210\u7b49\u5f85\u72b6\u6001\uff0c\u76f4\u5230\u961f\u5217\u6761\u4ef6\u6ee1\u8db3\u4e0d\u4e3a\u7a7a\uff0c\u7ebf\u7a0b\u88ab\u5524\u9192\u540e\uff0c<code>getTask()<\/code>\u65b9\u6cd5\u624d\u4f1a\u8fd4\u56de\u3002<\/p>\n\n\n\n<p>\u56e0\u4e3a<code>BlockingQueue<\/code>\u975e\u5e38\u6709\u7528\uff0c\u6240\u4ee5\u6211\u4eec\u4e0d\u5fc5\u81ea\u5df1\u7f16\u5199\uff0c\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528Java\u6807\u51c6\u5e93\u7684<code>java.util.concurrent<\/code>\u5305\u63d0\u4f9b\u7684\u7ebf\u7a0b\u5b89\u5168\u7684\u96c6\u5408\uff1a<code>ArrayBlockingQueue<\/code>\u3002<\/p>\n\n\n\n<p>\u9664\u4e86<code>BlockingQueue<\/code>\u5916\uff0c\u9488\u5bf9<code>List<\/code>\u3001<code>Map<\/code>\u3001<code>Set<\/code>\u3001<code>Deque<\/code>\u7b49\uff0c<code>java.util.concurrent<\/code>\u5305\u4e5f\u63d0\u4f9b\u4e86\u5bf9\u5e94\u7684\u5e76\u53d1\u96c6\u5408\u7c7b\u3002\u6211\u4eec\u5f52\u7eb3\u4e00\u4e0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>interface<\/th><th>non-thread-safe<\/th><th>thread-safe<\/th><\/tr><\/thead><tbody><tr><td>List<\/td><td>ArrayList<\/td><td>CopyOnWriteArrayList<\/td><\/tr><tr><td>Map<\/td><td>HashMap<\/td><td>ConcurrentHashMap<\/td><\/tr><tr><td>Set<\/td><td>HashSet \/ TreeSet<\/td><td>CopyOnWriteArraySet<\/td><\/tr><tr><td>Queue<\/td><td>ArrayDeque \/ LinkedList<\/td><td>ArrayBlockingQueue \/ LinkedBlockingQueue<\/td><\/tr><tr><td>Deque<\/td><td>ArrayDeque \/ LinkedList<\/td><td>LinkedBlockingDeque<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u4f7f\u7528\u8fd9\u4e9b\u5e76\u53d1\u96c6\u5408\u4e0e\u4f7f\u7528\u975e\u7ebf\u7a0b\u5b89\u5168\u7684\u96c6\u5408\u7c7b\u5b8c\u5168\u76f8\u540c\u3002\u6211\u4eec\u4ee5<code>ConcurrentHashMap<\/code>\u4e3a\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Map&lt;String, String&gt; map = new ConcurrentHashMap&lt;&gt;();\n\/\/ \u5728\u4e0d\u540c\u7684\u7ebf\u7a0b\u8bfb\u5199:\nmap.put(\"A\", \"1\");\nmap.put(\"B\", \"2\");\nmap.get(\"A\", \"1\");\n<\/code><\/pre>\n\n\n\n<p>\u56e0\u4e3a\u6240\u6709\u7684\u540c\u6b65\u548c\u52a0\u9501\u7684\u903b\u8f91\u90fd\u5728\u96c6\u5408\u5185\u90e8\u5b9e\u73b0\uff0c\u5bf9\u5916\u90e8\u8c03\u7528\u8005\u6765\u8bf4\uff0c\u53ea\u9700\u8981\u6b63\u5e38\u6309\u63a5\u53e3\u5f15\u7528\uff0c\u5176\u4ed6\u4ee3\u7801\u548c\u539f\u6765\u7684\u975e\u7ebf\u7a0b\u5b89\u5168\u4ee3\u7801\u5b8c\u5168\u4e00\u6837\u3002\u5373\u5f53\u6211\u4eec\u9700\u8981\u591a\u7ebf\u7a0b\u8bbf\u95ee\u65f6\uff0c\u628a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Map&lt;String, String&gt; map = new HashMap&lt;&gt;();\n<\/code><\/pre>\n\n\n\n<p>\u6539\u4e3a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Map&lt;String, String&gt; map = new ConcurrentHashMap&lt;&gt;();\n<\/code><\/pre>\n\n\n\n<p>\u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n\n\n\n<p><code>java.util.Collections<\/code>\u5de5\u5177\u7c7b\u8fd8\u63d0\u4f9b\u4e86\u4e00\u4e2a\u65e7\u7684\u7ebf\u7a0b\u5b89\u5168\u96c6\u5408\u8f6c\u6362\u5668\uff0c\u53ef\u4ee5\u8fd9\u4e48\u7528\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Map unsafeMap = new HashMap();\nMap threadSafeMap = Collections.synchronizedMap(unsafeMap);\n<\/code><\/pre>\n\n\n\n<p>\u4f46\u662f\u5b83\u5b9e\u9645\u4e0a\u662f\u7528\u4e00\u4e2a\u5305\u88c5\u7c7b\u5305\u88c5\u4e86\u975e\u7ebf\u7a0b\u5b89\u5168\u7684<code>Map<\/code>\uff0c\u7136\u540e\u5bf9\u6240\u6709\u8bfb\u5199\u65b9\u6cd5\u90fd\u7528<code>synchronized<\/code>\u52a0\u9501\uff0c\u8fd9\u6837\u83b7\u5f97\u7684\u7ebf\u7a0b\u5b89\u5168\u96c6\u5408\u7684\u6027\u80fd\u6bd4<code>java.util.concurrent<\/code>\u96c6\u5408\u8981\u4f4e\u5f88\u591a\uff0c\u6240\u4ee5\u4e0d\u63a8\u8350\u4f7f\u7528\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7ebf\u7a0b\u5b89\u5168\u7684\u96c6\u5408\u7c7b<\/h3>\n\n\n\n<ol start=\"1\">\n<li><strong><code>java.util.concurrent<\/code>\u5305 <\/strong>\uff1a\n<ul>\n<li><strong><code>ConcurrentHashMap<\/code> <\/strong>\uff1a\u7ebf\u7a0b\u5b89\u5168\u7684\u54c8\u5e0c\u8868\u5b9e\u73b0\uff0c\u652f\u6301\u9ad8\u5e76\u53d1\u8bbf\u95ee\u3002<\/li>\n\n\n\n<li><strong><code>CopyOnWriteArrayList<\/code> <\/strong>\uff1a\u7ebf\u7a0b\u5b89\u5168\u7684\u5217\u8868\u5b9e\u73b0\uff0c\u9002\u7528\u4e8e\u8bfb\u591a\u5199\u5c11\u7684\u573a\u666f\u3002<\/li>\n\n\n\n<li><strong><code>CopyOnWriteArraySet<\/code> <\/strong>\uff1a\u57fa\u4e8e<code>CopyOnWriteArrayList<\/code>\u7684\u7ebf\u7a0b\u5b89\u5168\u96c6\u5408\u3002<\/li>\n\n\n\n<li><strong><code>ConcurrentLinkedQueue<\/code> <\/strong>\uff1a\u7ebf\u7a0b\u5b89\u5168\u7684\u65e0\u754c\u975e\u963b\u585e\u961f\u5217\u3002<\/li>\n\n\n\n<li><strong><code>BlockingQueue<\/code>\u63a5\u53e3\u53ca\u5176\u5b9e\u73b0 <\/strong>\uff1a\n<ul>\n<li><strong><code>ArrayBlockingQueue<\/code> <\/strong>\uff1a\u6709\u754c\u963b\u585e\u961f\u5217\u3002<\/li>\n\n\n\n<li><strong><code>LinkedBlockingQueue<\/code> <\/strong>\uff1a\u53ef\u9009\u6709\u754c\u7684\u963b\u585e\u961f\u5217\u3002<\/li>\n\n\n\n<li><strong><code>PriorityBlockingQueue<\/code> <\/strong>\uff1a\u65e0\u754c\u963b\u585e\u4f18\u5148\u7ea7\u961f\u5217\u3002<\/li>\n\n\n\n<li><strong><code>DelayQueue<\/code> <\/strong>\uff1a\u65e0\u754c\u963b\u585e\u5ef6\u8fdf\u961f\u5217\u3002<\/li>\n\n\n\n<li><strong><code>SynchronousQueue<\/code> <\/strong>\uff1a\u4e0d\u5b58\u50a8\u5143\u7d20\u7684\u963b\u585e\u961f\u5217\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>ConcurrentSkipListMap<\/code> <\/strong>\uff1a\u7ebf\u7a0b\u5b89\u5168\u7684\u8df3\u8dc3\u8868\u5b9e\u73b0\uff0c\u652f\u6301\u9ad8\u6548\u7684\u5e76\u53d1\u8bbf\u95ee\u3002<\/li>\n\n\n\n<li><strong><code>ConcurrentSkipListSet<\/code> <\/strong>\uff1a\u57fa\u4e8e<code>ConcurrentSkipListMap<\/code>\u7684\u7ebf\u7a0b\u5b89\u5168\u96c6\u5408\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>java.util.Collections<\/code>\u5de5\u5177\u7c7b <\/strong>\uff1a\n<ul>\n<li><strong><code>Collections.synchronizedList(List&lt;T&gt; list)<\/code> <\/strong>\uff1a\u8fd4\u56de\u6307\u5b9a\u5217\u8868\u7684\u540c\u6b65\uff08\u7ebf\u7a0b\u5b89\u5168\uff09\u5305\u88c5\u5668\u3002<\/li>\n\n\n\n<li><strong><code>Collections.synchronizedSet(Set&lt;T&gt; s)<\/code> <\/strong>\uff1a\u8fd4\u56de\u6307\u5b9a\u96c6\u5408\u7684\u540c\u6b65\uff08\u7ebf\u7a0b\u5b89\u5168\uff09\u5305\u88c5\u5668\u3002<\/li>\n\n\n\n<li><strong><code>Collections.synchronizedMap(Map&lt;K,V&gt; m)<\/code> <\/strong>\uff1a\u8fd4\u56de\u6307\u5b9a\u6620\u5c04\u7684\u540c\u6b65\uff08\u7ebf\u7a0b\u5b89\u5168\uff09\u5305\u88c5\u5668\u3002<\/li>\n\n\n\n<li><strong><code>Collections.synchronizedSortedSet(SortedSet&lt;T&gt; s)<\/code> <\/strong>\uff1a\u8fd4\u56de\u6307\u5b9a\u6392\u5e8f\u96c6\u5408\u7684\u540c\u6b65\uff08\u7ebf\u7a0b\u5b89\u5168\uff09\u5305\u88c5\u5668\u3002<\/li>\n\n\n\n<li><strong><code>Collections.synchronizedSortedMap(SortedMap&lt;K,V&gt; m)<\/code> <\/strong>\uff1a\u8fd4\u56de\u6307\u5b9a\u6392\u5e8f\u6620\u5c04\u7684\u540c\u6b65\uff08\u7ebf\u7a0b\u5b89\u5168\uff09\u5305\u88c5\u5668\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">\u5176\u4ed6\u7ebf\u7a0b\u5b89\u5168\u7684\u7c7b<\/h3>\n\n\n\n<ol start=\"1\">\n<li><strong><code>java.lang<\/code>\u5305 <\/strong>\uff1a\n<ul>\n<li><strong><code>String<\/code> <\/strong>\uff1a\u867d\u7136<code>String<\/code>\u5bf9\u8c61\u672c\u8eab\u662f\u4e0d\u53ef\u53d8\u7684\uff0c\u4f46\u5f15\u7528\u662f\u53ef\u53d8\u7684\uff0c\u9700\u8981\u989d\u5916\u7684\u540c\u6b65\u673a\u5236\u6765\u786e\u4fdd\u5f15\u7528\u7684\u5b89\u5168\u6027\u3002<\/li>\n\n\n\n<li><strong><code>StringBuilder<\/code> <\/strong>\u548c <strong><code>StringBuffer<\/code> <\/strong>\uff1a\n<ul>\n<li><strong><code>StringBuffer<\/code> <\/strong>\uff1a\u7ebf\u7a0b\u5b89\u5168\u7684\u53ef\u53d8\u5b57\u7b26\u5e8f\u5217\u3002<\/li>\n\n\n\n<li><strong><code>StringBuilder<\/code> <\/strong>\uff1a\u975e\u7ebf\u7a0b\u5b89\u5168\u7684\u53ef\u53d8\u5b57\u7b26\u5e8f\u5217\uff0c\u6027\u80fd\u66f4\u9ad8\uff0c\u9002\u7528\u4e8e\u5355\u7ebf\u7a0b\u73af\u5883\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>java.util.concurrent.atomic<\/code>\u5305 <\/strong>\uff1a\n<ul>\n<li><strong><code>AtomicInteger<\/code> <\/strong>\uff1a\u63d0\u4f9b\u539f\u5b50\u64cd\u4f5c\u7684\u6574\u6570\u7c7b\u3002<\/li>\n\n\n\n<li><strong><code>AtomicLong<\/code> <\/strong>\uff1a\u63d0\u4f9b\u539f\u5b50\u64cd\u4f5c\u7684\u957f\u6574\u6570\u7c7b\u3002<\/li>\n\n\n\n<li><strong><code>AtomicBoolean<\/code> <\/strong>\uff1a\u63d0\u4f9b\u539f\u5b50\u64cd\u4f5c\u7684\u5e03\u5c14\u7c7b\u3002<\/li>\n\n\n\n<li><strong><code>AtomicReference&lt;V&gt;<\/code> <\/strong>\uff1a\u63d0\u4f9b\u539f\u5b50\u64cd\u4f5c\u7684\u5bf9\u8c61\u5f15\u7528\u3002<\/li>\n\n\n\n<li><strong><code>AtomicIntegerArray<\/code> <\/strong>\uff1a\u63d0\u4f9b\u539f\u5b50\u64cd\u4f5c\u7684\u6574\u6570\u6570\u7ec4\u3002<\/li>\n\n\n\n<li><strong><code>AtomicLongArray<\/code> <\/strong>\uff1a\u63d0\u4f9b\u539f\u5b50\u64cd\u4f5c\u7684\u957f\u6574\u6570\u6570\u7ec4\u3002<\/li>\n\n\n\n<li><strong><code>AtomicReferenceArray&lt;V&gt;<\/code> <\/strong>\uff1a\u63d0\u4f9b\u539f\u5b50\u64cd\u4f5c\u7684\u5bf9\u8c61\u6570\u7ec4\u5f15\u7528\u3002<\/li>\n\n\n\n<li><strong><code>AtomicIntegerFieldUpdater&lt;T&gt;<\/code> <\/strong>\uff1a\u63d0\u4f9b\u5bf9\u6307\u5b9a\u7c7b\u7684<code>volatile int<\/code>\u5b57\u6bb5\u7684\u539f\u5b50\u66f4\u65b0\u3002<\/li>\n\n\n\n<li><strong><code>AtomicLongFieldUpdater&lt;T&gt;<\/code> <\/strong>\uff1a\u63d0\u4f9b\u5bf9\u6307\u5b9a\u7c7b\u7684<code>volatile long<\/code>\u5b57\u6bb5\u7684\u539f\u5b50\u66f4\u65b0\u3002<\/li>\n\n\n\n<li><strong><code>AtomicReferenceFieldUpdater&lt;T,V&gt;<\/code> <\/strong>\uff1a\u63d0\u4f9b\u5bf9\u6307\u5b9a\u7c7b\u7684<code>volatile reference<\/code>\u5b57\u6bb5\u7684\u539f\u5b50\u66f4\u65b0\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>java.util.concurrent.locks<\/code>\u5305 <\/strong>\uff1a\n<ul>\n<li><strong><code>ReentrantLock<\/code> <\/strong>\uff1a\u53ef\u91cd\u5165\u7684\u4e92\u65a5\u9501\u3002<\/li>\n\n\n\n<li><strong><code>ReadWriteLock<\/code>\u63a5\u53e3\u53ca\u5176\u5b9e\u73b0 <\/strong>\uff1a\n<ul>\n<li><strong><code>ReentrantReadWriteLock<\/code> <\/strong>\uff1a\u652f\u6301\u8bfb\u5199\u9501\u7684\u5b9e\u73b0\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>Condition<\/code>\u63a5\u53e3 <\/strong>\uff1a\u4e0e<code>ReentrantLock<\/code>\u4e00\u8d77\u4f7f\u7528\uff0c\u63d0\u4f9b\u66f4\u7075\u6d3b\u7684\u7ebf\u7a0b\u901a\u4fe1\u673a\u5236\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>java.util.concurrent<\/code>\u5305\u4e2d\u7684\u5176\u4ed6\u7c7b <\/strong>\uff1a\n<ul>\n<li><strong><code>ExecutorService<\/code>\u63a5\u53e3\u53ca\u5176\u5b9e\u73b0 <\/strong>\uff1a\n<ul>\n<li><strong><code>ThreadPoolExecutor<\/code> <\/strong>\uff1a\u7ebf\u7a0b\u6c60\u7684\u5b9e\u73b0\u3002<\/li>\n\n\n\n<li><strong><code>ScheduledThreadPoolExecutor<\/code> <\/strong>\uff1a\u652f\u6301\u5b9a\u65f6\u4efb\u52a1\u7684\u7ebf\u7a0b\u6c60\u5b9e\u73b0\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>Future<\/code>\u63a5\u53e3\u53ca\u5176\u5b9e\u73b0 <\/strong>\uff1a\n<ul>\n<li><strong><code>FutureTask<\/code> <\/strong>\uff1a\u8868\u793a\u5f02\u6b65\u8ba1\u7b97\u7684\u7ed3\u679c\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong><code>CompletableFuture<\/code> <\/strong>\uff1a\u63d0\u4f9b\u66f4\u5f3a\u5927\u7684\u5f02\u6b65\u7f16\u7a0b\u652f\u6301\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<p>Java\u7684<code>java.util.concurrent<\/code>\u5305\u9664\u4e86\u63d0\u4f9b\u5e95\u5c42\u9501\u3001\u5e76\u53d1\u96c6\u5408\u5916\uff0c\u8fd8\u63d0\u4f9b\u4e86\u4e00\u7ec4\u539f\u5b50\u64cd\u4f5c\u7684\u5c01\u88c5\u7c7b\uff0c\u5b83\u4eec\u4f4d\u4e8e<code>java.util.concurrent.atomic<\/code>\u5305\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u4ee5<code>AtomicInteger<\/code>\u4e3a\u4f8b\uff0c\u5b83\u63d0\u4f9b\u7684\u4e3b\u8981\u64cd\u4f5c\u6709\uff1a<\/p>\n\n\n\n<ul>\n<li>\u589e\u52a0\u503c\u5e76\u8fd4\u56de\u65b0\u503c\uff1a<code>int addAndGet(int delta)<\/code><\/li>\n\n\n\n<li>\u52a01\u540e\u8fd4\u56de\u65b0\u503c\uff1a<code>int incrementAndGet()<\/code><\/li>\n\n\n\n<li>\u83b7\u53d6\u5f53\u524d\u503c\uff1a<code>int get()<\/code><\/li>\n\n\n\n<li>\u7528CAS\u65b9\u5f0f\u8bbe\u7f6e\uff1a<code>int compareAndSet(int expect, int update)<\/code><\/li>\n<\/ul>\n\n\n\n<p>Atomic\u7c7b\u662f\u901a\u8fc7\u65e0\u9501\uff08lock-free\uff09\u7684\u65b9\u5f0f\u5b9e\u73b0\u7684\u7ebf\u7a0b\u5b89\u5168\uff08thread-safe\uff09\u8bbf\u95ee\u3002\u5b83\u7684\u4e3b\u8981\u539f\u7406\u662f\u5229\u7528\u4e86CAS\uff1aCompare and Set\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u6211\u4eec\u81ea\u5df1\u901a\u8fc7CAS\u7f16\u5199<code>incrementAndGet()<\/code>\uff0c\u5b83\u5927\u6982\u957f\u8fd9\u6837\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>public int incrementAndGet(AtomicInteger var) {\n    int prev, next;\n    do {\n        prev = var.get();\n        next = prev + 1;\n    } while ( ! var.compareAndSet(prev, next));\n    return next;\n}\n<\/code><\/pre>\n\n\n\n<p>CAS\u662f\u6307\uff0c\u5728\u8fd9\u4e2a\u64cd\u4f5c\u4e2d\uff0c\u5982\u679c<code>AtomicInteger<\/code>\u7684\u5f53\u524d\u503c\u662f<code>prev<\/code>\uff0c\u90a3\u4e48\u5c31\u66f4\u65b0\u4e3a<code>next<\/code>\uff0c\u8fd4\u56de<code>true<\/code>\u3002\u5982\u679c<code>AtomicInteger<\/code>\u7684\u5f53\u524d\u503c\u4e0d\u662f<code>prev<\/code>\uff0c\u5c31\u4ec0\u4e48\u4e5f\u4e0d\u5e72\uff0c\u8fd4\u56de<code>false<\/code>\u3002\u901a\u8fc7CAS\u64cd\u4f5c\u5e76\u914d\u5408<code>do ... while<\/code>\u5faa\u73af\uff0c\u5373\u4f7f\u5176\u4ed6\u7ebf\u7a0b\u4fee\u6539\u4e86<code>AtomicInteger<\/code>\u7684\u503c\uff0c\u6700\u7ec8\u7684\u7ed3\u679c\u4e5f\u662f\u6b63\u786e\u7684\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u5229\u7528<code>AtomicLong<\/code>\u53ef\u4ee5\u7f16\u5199\u4e00\u4e2a\u591a\u7ebf\u7a0b\u5b89\u5168\u7684\u5168\u5c40\u552f\u4e00ID\u751f\u6210\u5668\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>class IdGenerator {\n    AtomicLong var = new AtomicLong(0);\n\n    public long getNextId() {\n        return var.incrementAndGet();\n    }\n}\n<\/code><\/pre>\n\n\n\n<p>\u901a\u5e38\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u5e76\u4e0d\u9700\u8981\u76f4\u63a5\u7528<code>do ... while<\/code>\u5faa\u73af\u8c03\u7528<code>compareAndSet<\/code>\u5b9e\u73b0\u590d\u6742\u7684\u5e76\u53d1\u64cd\u4f5c\uff0c\u800c\u662f\u7528<code>incrementAndGet()<\/code>\u8fd9\u6837\u7684\u5c01\u88c5\u597d\u7684\u65b9\u6cd5\uff0c\u56e0\u6b64\uff0c\u4f7f\u7528\u8d77\u6765\u975e\u5e38\u7b80\u5355\u3002<\/p>\n\n\n\n<p>\u5728\u9ad8\u5ea6\u7ade\u4e89\u7684\u60c5\u51b5\u4e0b\uff0c\u8fd8\u53ef\u4ee5\u4f7f\u7528Java 8\u63d0\u4f9b\u7684<code>LongAdder<\/code>\u548c<code>LongAccumulator<\/code>\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u7ebf\u7a0b\u540c\u6b65\u662f\u4e2a\u5f88\u56f0\u96be\u7684\u5b9e\u73b0\uff0c\u56e0\u4e3a\u5e76&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":821,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[147,212],"_links":{"self":[{"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/posts\/820"}],"collection":[{"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=820"}],"version-history":[{"count":1,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/posts\/820\/revisions"}],"predecessor-version":[{"id":822,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/posts\/820\/revisions\/822"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/media\/821"}],"wp:attachment":[{"href":"https:\/\/www.ikaros.love\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=820"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=820"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=820"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}