{"id":202843,"date":"2025-05-22T11:46:56","date_gmt":"2025-05-22T03:46:56","guid":{"rendered":"https:\/\/server.hk\/cnblog\/202843\/"},"modified":"2025-05-22T11:46:56","modified_gmt":"2025-05-22T03:46:56","slug":"java%e5%87%bd%e6%95%b0%e7%9a%84%e6%80%a7%e8%83%bd%e5%a6%82%e4%bd%95%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/202843\/","title":{"rendered":"Java\u51fd\u6570\u7684\u6027\u80fd\u5982\u4f55\uff1f"},"content":{"rendered":"<p><b><\/b>     <\/p>\n<h1>Java\u51fd\u6570\u7684\u6027\u80fd\u5982\u4f55\uff1f<\/h1>\n<p>\u4e00\u5206\u8015\u8018\uff0c\u4e00\u5206\u6536\u83b7\uff01\u65e2\u7136\u90fd\u6253\u5f00\u8fd9\u7bc7<span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\">\u300aJava\u51fd\u6570\u7684\u6027\u80fd\u5982\u4f55\uff1f\u300b<\/span>\uff0c\u5c31\u575a\u6301\u770b\u4e0b\u53bb\uff0c\u5b66\u4e0b\u53bb\u5427\uff01\u672c\u6587\u4e3b\u8981\u4f1a\u7ed9\u5927\u5bb6\u8bb2\u5230<span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\"><\/span>\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u5927\u5bb6\u5bf9\u672c\u6587\u6709\u597d\u7684\u5efa\u8bae\u6216\u8005\u770b\u5230\u6709\u4e0d\u8db3\u4e4b\u5904\uff0c\u975e\u5e38\u6b22\u8fce\u5927\u5bb6\u79ef\u6781\u63d0\u51fa\uff01\u5728\u540e\u7eed\u6587\u7ae0\u6211\u4f1a\u7ee7\u7eed\u66f4\u65b0<span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\">\u6587\u7ae0<\/span>\u76f8\u5173\u7684\u5185\u5bb9\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u90fd\u6709\u6240\u5e2e\u52a9\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241026\/1729949505671cef412b76f.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>Java \u51fd\u6570\u7684\u6027\u80fd<\/strong><\/p>\n<p>Java \u51fd\u6570\u7684\u6027\u80fd\u53d6\u51b3\u4e8e\u591a\u79cd\u56e0\u7d20\uff0c\u5305\u62ec\uff1a<\/p>\n<ul>\n<li>\u51fd\u6570\u5927\u5c0f\u548c\u590d\u6742\u5ea6<\/li>\n<li>\u8f93\u5165\u548c\u8f93\u51fa\u53c2\u6570\u7684\u5927\u5c0f\u548c\u7c7b\u578b<\/li>\n<li>\u51fd\u6570\u8c03\u7528\u7684\u9891\u7387<\/li>\n<li>JVM \u914d\u7f6e<\/li>\n<\/ul>\n<p><strong>\u5f71\u54cd Java \u51fd\u6570\u6027\u80fd\u7684\u56e0\u7d20<\/strong><\/p>\n<ul>\n<li><strong>\u51fd\u6570\u5927\u5c0f\u548c\u590d\u6742\u5ea6\uff1a<\/strong>\u51fd\u6570\u8d8a\u590d\u6742\u4e14\u8c03\u7528\u6808\u8d8a\u6df1\uff0c\u5176\u6267\u884c\u65f6\u95f4\u5c31\u8d8a\u957f\u3002<\/li>\n<li><strong>\u8f93\u5165\u548c\u8f93\u51fa\u53c2\u6570\uff1a<\/strong>\u53c2\u6570\u7684\u5927\u5c0f\u548c\u7c7b\u578b\u4f1a\u5f71\u54cd\u51fd\u6570\u8c03\u7528\u7684\u5f00\u9500\u3002\u4f8b\u5982\uff0c\u4f20\u9012\u5927\u91cf\u5bf9\u8c61\u4f5c\u4e3a\u53c2\u6570\u6bd4\u4f20\u9012\u57fa\u672c\u7c7b\u578b\u53c2\u6570\u66f4\u8017\u65f6\u3002<\/li>\n<li><strong>\u51fd\u6570\u8c03\u7528\u7684\u9891\u7387\uff1a<\/strong>\u9891\u7e41\u8c03\u7528\u7684\u51fd\u6570\u4f1a\u6bd4\u4e0d\u7ecf\u5e38\u8c03\u7528\u7684\u51fd\u6570\u5bf9\u6027\u80fd\u4ea7\u751f\u66f4\u5927\u7684\u5f71\u54cd\u3002<\/li>\n<li><strong>JVM \u914d\u7f6e\uff1a<\/strong>JVM \u7684\u5806\u5927\u5c0f\u3001\u5783\u573e\u6536\u96c6\u7b56\u7565\u548c\u5176\u4ed6\u914d\u7f6e\u9009\u9879\u4f1a\u5f71\u54cd\u51fd\u6570\u7684\u6027\u80fd\u3002<\/li>\n<\/ul>\n<p><strong>\u5b9e\u6218\u6848\u4f8b<\/strong><\/p>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e2a\u5728\u4e0d\u540c\u8f93\u5165\u5927\u5c0f\u4e0b\u6bd4\u8f83\u4e24\u4e2a Java \u51fd\u6570\u6027\u80fd\u7684\u5b9e\u6218\u6848\u4f8b\uff1a<\/p>\n<pre>public class FunctionPerformanceTest {\n\n    \/\/ \u51fd\u6570 1\uff1a\u4f7f\u7528 StringBuilder \u8fde\u63a5\u5b57\u7b26\u4e32\n    public static String concatStrings1(int numStrings) {\n        StringBuilder sb = new StringBuilder();\n        for (int i = 0; i &lt; numStrings; i++) {\n            sb.append(\"String \" + i);\n        }\n        return sb.toString();\n    }\n\n    \/\/ \u51fd\u6570 2\uff1a\u4f7f\u7528 + \u64cd\u4f5c\u7b26\u8fde\u63a5\u5b57\u7b26\u4e32\n    public static String concatStrings2(int numStrings) {\n        String result = \"\";\n        for (int i = 0; i &lt; numStrings; i++) {\n            result += \"String \" + i;\n        }\n        return result;\n    }\n\n    public static void main(String[] args) {\n        \/\/ \u8f93\u5165\u5b57\u7b26\u4e32\u6570\u91cf\n        int numStrings = 100000;\n\n        \/\/ \u6d4b\u91cf\u51fd\u6570 1 \u7684\u6267\u884c\u65f6\u95f4\n        long startTime = System.nanoTime();\n        String result1 = concatStrings1(numStrings);\n        long endTime = System.nanoTime();\n        long time1 = endTime - startTime;\n\n        \/\/ \u6d4b\u91cf\u51fd\u6570 2 \u7684\u6267\u884c\u65f6\u95f4\n        startTime = System.nanoTime();\n        String result2 = concatStrings2(numStrings);\n        endTime = System.nanoTime();\n        long time2 = endTime - startTime;\n\n        \/\/ \u6253\u5370\u7ed3\u679c\n        System.out.println(\"\u51fd\u6570 1 (StringBuilder) \u6267\u884c\u65f6\u95f4\uff1a\" + time1 + \" \u7eb3\u79d2\");\n        System.out.println(\"\u51fd\u6570 2 (+ \u64cd\u4f5c\u7b26) \u6267\u884c\u65f6\u95f4\uff1a\" + time2 + \" \u7eb3\u79d2\");\n    }\n}<\/pre>\n<p><strong>\u7ed3\u679c<\/strong><\/p>\n<p>\u8f93\u51fa\u7ed3\u679c\u5c06\u663e\u793a\u51fd\u6570 1 (StringBuilder) \u7684\u6027\u80fd\u4f18\u4e8e\u51fd\u6570 2 (\u64cd\u4f5c\u7b26)\uff0c\u56e0\u4e3a StringBuilder \u5728\u8fde\u63a5\u5927\u91cf\u5b57\u7b26\u4e32\u65f6\u66f4\u6709\u6548\u7387\u3002<\/p>\n<p>\u7406\u8bba\u8981\u638c\u63e1\uff0c\u5b9e\u64cd\u4e0d\u80fd\u843d\uff01\u4ee5\u4e0a\u5173\u4e8e\u300aJava\u51fd\u6570\u7684\u6027\u80fd\u5982\u4f55\uff1f\u300b\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u5927\u5bb6\u90fd\u638c\u63e1\u4e86\u5427\uff01\u5982\u679c\u60f3\u8981\u7ee7\u7eed\u63d0\u5347\u81ea\u5df1\u7684\u80fd\u529b\uff0c\u90a3\u4e48\u5c31\u6765\u5173\u6ce8\u516c\u4f17\u53f7\u5427\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Java\u51fd\u6570\u7684\u6027\u80fd\u5982\u4f55\uff1f \u4e00\u5206\u8015&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-202843","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202843","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=202843"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202843\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=202843"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=202843"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=202843"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}