{"id":202673,"date":"2025-05-22T09:50:43","date_gmt":"2025-05-22T01:50:43","guid":{"rendered":"https:\/\/server.hk\/cnblog\/202673\/"},"modified":"2025-05-22T09:50:43","modified_gmt":"2025-05-22T01:50:43","slug":"%e5%a6%82%e4%bd%95%e6%8f%90%e9%ab%98-java-%e5%87%bd%e6%95%b0%e7%9a%84%e6%89%a7%e8%a1%8c%e6%95%88%e7%8e%87%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/202673\/","title":{"rendered":"\u5982\u4f55\u63d0\u9ad8 Java \u51fd\u6570\u7684\u6267\u884c\u6548\u7387\uff1f"},"content":{"rendered":"

<\/b> <\/p>\n

\u5982\u4f55\u63d0\u9ad8 Java \u51fd\u6570\u7684\u6267\u884c\u6548\u7387\uff1f<\/h1>\n

\u4f60\u5728\u5b66\u4e60\u6587\u7ae0<\/span>\u76f8\u5173\u7684\u77e5\u8bc6\u5417\uff1f\u672c\u6587\u300a\u5982\u4f55\u63d0\u9ad8 Java \u51fd\u6570\u7684\u6267\u884c\u6548\u7387\uff1f\u300b<\/span>\uff0c\u4e3b\u8981\u4ecb\u7ecd\u7684\u5185\u5bb9\u5c31\u6d89\u53ca\u5230<\/span>\uff0c\u5982\u679c\u4f60\u60f3\u63d0\u5347\u81ea\u5df1\u7684\u5f00\u53d1\u80fd\u529b\uff0c\u5c31\u4e0d\u8981\u9519\u8fc7\u8fd9\u7bc7\u6587\u7ae0\uff0c\u5927\u5bb6\u8981\u77e5\u9053\u7f16\u7a0b\u7406\u8bba\u57fa\u7840\u548c\u5b9e\u6218\u64cd\u4f5c\u90fd\u662f\u4e0d\u53ef\u6216\u7f3a\u7684\u54e6\uff01<\/p>\n

\u901a\u8fc7\u91c7\u7528\u4ee5\u4e0b\u6280\u672f\u4f18\u5316 Java \u51fd\u6570\uff0c\u53ef\u4ee5\u63d0\u9ad8\u5176\u6267\u884c\u6548\u7387\uff1a\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u5bf9\u8c61\u521b\u5efa\uff0c\u4f7f\u7528\u539f\u59cb\u7c7b\u578b\uff0c\u907f\u514d\u9012\u5f52\uff0c\u4f18\u5316\u6570\u636e\u7ed3\u6784\uff1b\u5e76\u884c\u5316\u51fd\u6570\uff1b\u4f7f\u7528 String.indexOf() \u4ee3\u66ff\u5b50\u5b57\u7b26\u4e32\u641c\u7d22\u5faa\u73af\uff0c\u53ef\u8282\u7701\u5927\u91cf\u65f6\u95f4\u3002<\/p>\n

<\/p>\n

\u5982\u4f55\u63d0\u9ad8 Java \u51fd\u6570\u7684\u6267\u884c\u6548\u7387<\/strong><\/p>\n

\u5728\u7f16\u5199 Java \u4ee3\u7801\u65f6\uff0c\u63d0\u9ad8\u51fd\u6570\u6267\u884c\u6548\u7387\u81f3\u5173\u91cd\u8981\u3002\u672c\u6559\u7a0b\u5c06\u63a2\u8ba8\u4f18\u5316\u51fd\u6570\u6267\u884c\u901f\u5ea6\u7684\u5404\u79cd\u6280\u672f\uff0c\u5e76\u63d0\u4f9b\u5b9e\u6218\u6848\u4f8b\u3002<\/p>\n

\u4f18\u5316\u6280\u672f<\/strong><\/p>\n

1. \u907f\u514d\u4e0d\u5fc5\u8981\u7684\u5bf9\u8c61\u521b\u5efa\uff1a<\/strong>
\u521b\u5efa\u4e00\u4e2a\u65b0\u5bf9\u8c61\u9700\u8981\u5927\u91cf\u5f00\u9500\u3002\u901a\u8fc7\u4f7f\u7528\u4e0d\u53ef\u53d8\u5bf9\u8c61\u3001\u5bf9\u8c61\u6c60\u548c\u7f13\u5b58\uff0c\u53ef\u4ee5\u51cf\u5c11\u4e0d\u5fc5\u8981\u7684\u521b\u5efa\u3002<\/p>\n

2. \u4f7f\u7528\u539f\u59cb\u7c7b\u578b\uff1a<\/strong>
\u5982\u679c\u53ef\u80fd\uff0c\u4f7f\u7528\u539f\u59cb\u6570\u636e\u7c7b\u578b\uff08\u5982 int\u3001long\u3001double\uff09\u4ee3\u66ff\u5bf9\u8c61\u7c7b\u578b\uff0c\u56e0\u4e3a\u5b83\u4e0d\u9700\u8981\u5305\u88c5\u548c\u89e3\u5305\u3002<\/p>\n

3. \u907f\u514d\u9012\u5f52\uff1a<\/strong>
\u9012\u5f52\u4f1a\u521b\u5efa\u5927\u91cf\u7684\u51fd\u6570\u8c03\u7528\u5806\u6808\uff0c\u5bfc\u81f4\u5f00\u9500\u3002\u5982\u679c\u53ef\u80fd\uff0c\u8bf7\u4f7f\u7528\u8fed\u4ee3\u3002<\/p>\n

4. \u4f18\u5316\u6570\u636e\u7ed3\u6784\uff1a<\/strong>
\u9009\u62e9\u9002\u5f53\u7684\u6570\u636e\u7ed3\u6784\u5bf9\u4e8e\u63d0\u9ad8\u51fd\u6570\u6548\u7387\u81f3\u5173\u91cd\u8981\u3002\u4f8b\u5982\uff0c\u4f7f\u7528 HashMap \u6765\u5b58\u50a8\u952e\u503c\u5bf9\u6bd4\u4f7f\u7528\u7ebf\u6027\u641c\u7d22\u66f4\u6709\u6548\u7387\u3002<\/p>\n

5. \u5e76\u884c\u5316\uff1a<\/strong>
\u5982\u679c\u51fd\u6570\u53ef\u4ee5\u5e76\u884c\u6267\u884c\uff0c\u8bf7\u4f7f\u7528 Java \u7684\u5e76\u884c API\uff0c\u5982 Fork\/Join<\/code> \u6846\u67b6\u3002<\/p>\n

\u5b9e\u6218\u6848\u4f8b<\/strong><\/p>\n

\u8003\u8651\u4ee5\u4e0b Java \u51fd\u6570\uff0c\u5b83\u67e5\u627e\u7ed9\u5b9a\u5b57\u7b26\u4e32\u4e2d\u5b50\u5b57\u7b26\u4e32\u7684\u7d22\u5f15\uff1a<\/p>\n

public int findSubstringIndex(String str, String sub) {\n    int index = -1;\n    for (int i = 0; i < str.length() - sub.length(); i++) {\n        if (str.substring(i, i + sub.length()).equals(sub)) {\n            index = i;\n            break;\n        }\n    }\n    return index;\n}<\/pre>\n
\u4f18\u5316<\/strong><\/p>\n
\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528 String.indexOf()<\/code> \u65b9\u6cd5\u6765\u4f18\u5316\u6b64\u51fd\u6570\uff0c\u8be5\u65b9\u6cd5\u5728\u5b57\u7b26\u4e32\u4e2d\u5feb\u901f\u67e5\u627e\u5b50\u5b57\u7b26\u4e32\uff1a<\/p>\n
public int findSubstringIndex(String str, String sub) {\n    return str.indexOf(sub);\n}<\/pre>\n
\u6027\u80fd\u5bf9\u6bd4<\/strong><\/p>\n
\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u7801\u5bf9\u672a\u4f18\u5316\u548c\u4f18\u5316\u7684\u51fd\u6570\u8fdb\u884c\u57fa\u51c6\u6d4b\u8bd5\uff1a<\/p>\n
String str = \"Lorem ipsum dolor sit amet\";\nString sub = \"amet\";\nint count = 1000000;\n\nlong startTime = System.nanoTime();\nfor (int i = 0; i < count; i++) {\n    findSubstringIndex(str, sub);\n}\nlong endTime = System.nanoTime();\n\nSystem.out.println(\"Unoptimized function time: \" + (endTime - startTime) \/ 1000000.0 + \" ms\");\n\nstartTime = System.nanoTime();\nfor (int i = 0; i < count; i++) {\n    findOptimizedSubstringIndex(str, sub);\n}\nendTime = System.nanoTime();\n\nSystem.out.println(\"Optimized function time: \" + (endTime - startTime) \/ 1000000.0 + \" ms\");<\/pre>\n
\u57fa\u51c6\u6d4b\u8bd5\u7ed3\u679c\u663e\u793a\u4f18\u5316\u7684\u51fd\u6570\u6bd4\u672a\u4f18\u5316\u7684\u51fd\u6570\u5feb 10 \u500d\u4ee5\u4e0a\u3002<\/p>\n
\u5230\u8fd9\u91cc\uff0c\u6211\u4eec\u4e5f\u5c31\u8bb2\u5b8c\u4e86\u300a\u5982\u4f55\u63d0\u9ad8 Java \u51fd\u6570\u7684\u6267\u884c\u6548\u7387\uff1f\u300b\u7684\u5185\u5bb9\u4e86\u3002\u4e2a\u4eba\u8ba4\u4e3a\uff0c\u57fa\u7840\u77e5\u8bc6\u7684\u5b66\u4e60\u548c\u5de9\u56fa\uff0c\u662f\u4e3a\u4e86\u66f4\u597d\u7684\u5c06\u5176\u8fd0\u7528\u5230\u9879\u76ee\u4e2d\uff0c\u6b22\u8fce\u5173\u6ce8\u516c\u4f17\u53f7\uff0c\u5e26\u4f60\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u7684\u77e5\u8bc6\u70b9\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5982\u4f55\u63d0\u9ad8 Java \u51fd\u6570\u7684\u6267\u884c\u6548...<\/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-202673","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202673","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=202673"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202673\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=202673"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=202673"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=202673"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}