{"id":202930,"date":"2025-05-22T10:47:49","date_gmt":"2025-05-22T02:47:49","guid":{"rendered":"https:\/\/server.hk\/cnblog\/202930\/"},"modified":"2025-05-22T10:47:49","modified_gmt":"2025-05-22T02:47:49","slug":"%e4%bd%bf%e7%94%a8java%e5%87%bd%e6%95%b0%e5%bc%8f%e7%bc%96%e7%a8%8b%e8%a7%a3%e5%86%b3%e6%95%b0%e6%8d%ae%e5%a4%84%e7%90%86%e7%97%9b%e7%82%b9%e7%9a%84%e5%88%9b%e6%96%b0%e6%96%b9%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/202930\/","title":{"rendered":"\u4f7f\u7528Java\u51fd\u6570\u5f0f\u7f16\u7a0b\u89e3\u51b3\u6570\u636e\u5904\u7406\u75db\u70b9\u7684\u521b\u65b0\u65b9\u6cd5"},"content":{"rendered":"

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

\u4f7f\u7528Java\u51fd\u6570\u5f0f\u7f16\u7a0b\u89e3\u51b3\u6570\u636e\u5904\u7406\u75db\u70b9\u7684\u521b\u65b0\u65b9\u6cd5<\/h1>\n

\u5927\u5bb6\u597d\uff0c\u6211\u4eec\u53c8\u89c1\u9762\u4e86\u554a~\u672c\u6587\u300a\u4f7f\u7528Java\u51fd\u6570\u5f0f\u7f16\u7a0b\u89e3\u51b3\u6570\u636e\u5904\u7406\u75db\u70b9\u7684\u521b\u65b0\u65b9\u6cd5\u300b<\/span>\u7684\u5185\u5bb9\u4e2d\u5c06\u4f1a\u6d89\u53ca\u5230<\/span>\u7b49\u7b49\u3002\u5982\u679c\u4f60\u6b63\u5728\u5b66\u4e60\u6587\u7ae0<\/span>\u76f8\u5173\u77e5\u8bc6\uff0c\u6b22\u8fce\u5173\u6ce8\u6211\uff0c\u4ee5\u540e\u4f1a\u7ed9\u5927\u5bb6\u5e26\u6765\u66f4\u591a\u6587\u7ae0<\/span>\u76f8\u5173\u6587\u7ae0\uff0c\u5e0c\u671b\u6211\u4eec\u80fd\u4e00\u8d77\u8fdb\u6b65\uff01\u4e0b\u9762\u5c31\u5f00\u59cb\u672c\u6587\u7684\u6b63\u5f0f\u5185\u5bb9~<\/p>\n

\u51fd\u6570\u5f0f\u7f16\u7a0b\u4e3a\u6570\u636e\u5904\u7406\u75db\u70b9\u63d0\u4f9b\u4e86\u521b\u65b0\u89e3\u51b3\u65b9\u6848\uff0c\u5305\u62ec\uff1a\u6d41\u5904\u7406\uff1a\u4f7f\u7528 Stream API \u5bf9\u6570\u636e\u5e8f\u5217\u8fdb\u884c\u5e76\u884c\u548c\u60f0\u6027\u64cd\u4f5c\uff0c\u907f\u514d\u521b\u5efa\u5197\u4f59\u4e2d\u95f4\u96c6\u5408\u3002\u4e0d\u53ef\u53d8\u6027\uff1a\u5f3a\u8c03\u6570\u636e\u5728\u64cd\u4f5c\u8fc7\u7a0b\u4e2d\u4fdd\u6301\u4e0d\u53d8\uff0c\u6d88\u9664\u5e76\u53d1\u95ee\u9898\u5e76\u7b80\u5316\u63a8\u7406\u3002\u7ec4\u5408\uff1a\u4f7f\u7528 lambda \u8868\u8fbe\u5f0f\u521b\u5efa\u4e00\u4e2a\u53ef\u6839\u636e\u9700\u8981\u5b9a\u5236\u548c\u7ec4\u5408\u7684\u590d\u6742\u5904\u7406\u903b\u8f91\u3002\u5b9e\u6218\u6848\u4f8b\uff1a\u5229\u7528 Streams \u5904\u7406\u5927\u578b\u65e5\u5fd7\u6587\u4ef6\uff0c\u63d0\u53d6\u6709\u610f\u4e49\u7684\u4fe1\u606f\u3002<\/p>\n

<\/p>\n

\u4f7f\u7528 Java \u51fd\u6570\u5f0f\u7f16\u7a0b\u89e3\u51b3\u6570\u636e\u5904\u7406\u75db\u70b9\u7684\u521b\u65b0\u65b9\u6cd5<\/strong><\/p>\n

\u51fd\u6570\u5f0f\u7f16\u7a0b\uff0c\u4e00\u79cd\u4ee5\u51fd\u6570\u548c lambda \u8868\u8fbe\u5f0f\u4e3a\u4e2d\u5fc3\u7684\u5bf9\u95ee\u9898\u8fdb\u884c\u5efa\u6a21\u7684\u7f16\u7a0b\u98ce\u683c\uff0c\u8fd1\u5e74\u6765\u5728 Java \u5f00\u53d1\u4e2d\u83b7\u5f97\u4e86\u5e7f\u6cdb\u7684\u91c7\u7528\u3002\u5bf9\u4e8e\u5904\u7406\u5927\u91cf\u6570\u636e\u65f6\u7ecf\u5e38\u9047\u5230\u7684\u75db\u70b9\uff0c\u5b83\u63d0\u4f9b\u4e86\u4e00\u7cfb\u5217\u521b\u65b0\u7684\u89e3\u51b3\u65b9\u6848\u3002<\/p>\n

\u6d41\u5904\u7406<\/strong><\/p>\n

Streams API \u63d0\u4f9b\u4e86\u4e00\u4e2a\u4f18\u96c5\u4e14\u5065\u58ee\u7684\u6846\u67b6\uff0c\u7528\u4e8e\u5bf9\u6570\u636e\u5e8f\u5217\u8fdb\u884c\u5e76\u884c\u548c\u60f0\u6027\u64cd\u4f5c\u3002\u901a\u8fc7\u5229\u7528\u4e2d\u95f4\u8fd0\u7b97\uff08\u5982 map\u3001filter\u3001reduce\uff09\u7684\u7ec4\u5408\uff0c\u53ef\u4ee5\u8f7b\u677e\u6784\u5efa\u590d\u6742\u7684\u6570\u636e\u5904\u7406\u7ba1\u9053\uff0c\u907f\u514d\u521b\u5efa\u5197\u4f59\u7684\u4e2d\u95f4\u96c6\u5408\u3002<\/p>\n

List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);\n\n\/\/ \u4f7f\u7528 Stream API \u5bf9\u6570\u636e\u8fdb\u884c\u5e73\u65b9\u548c\nint sumOfSquares = numbers.stream()\n        .map(n -> n * n)  \/\/ \u5e73\u65b9\u6bcf\u4e2a\u5143\u7d20\n        .reduce(0, (a, b) -> a + b);  \/\/ \u5c06\u5e73\u65b9\u5143\u7d20\u76f8\u52a0<\/pre>\n
\u4e0d\u53ef\u53d8\u6027<\/strong><\/p>\n
\u51fd\u6570\u5f0f\u7f16\u7a0b\u5f3a\u8c03\u4e0d\u53ef\u53d8\u6027\uff0c\u5373\u6570\u636e\u5728\u64cd\u4f5c\u8fc7\u7a0b\u4e2d\u4fdd\u6301\u4e0d\u53d8\u3002\u8fd9\u6d88\u9664\u4e86\u5e38\u89c1\u7684\u5e76\u53d1\u95ee\u9898\uff0c\u5e76\u7b80\u5316\u4e86\u63a8\u7406\u548c\u6d4b\u8bd5\u3002Java \u4e2d\u4f7f\u7528 final \u5173\u952e\u5b57\u6216\u4e0d\u53ef\u53d8\u7c7b\uff08\u5982 Collections\u3001ImmutableMap\uff09\u6765\u5b9e\u73b0\u4e0d\u53ef\u53d8\u6027\u3002<\/p>\n
\/\/ \u521b\u5efa\u4e00\u4e2a\u4e0d\u53ef\u53d8 List\nList<Integer> immutableList = Collections.unmodifiableList(numbers);\n\n\/\/ \u5c1d\u8bd5\u4fee\u6539\u4e0d\u53ef\u53d8 List\uff08\u4f1a\u5f15\u53d1\u5f02\u5e38\uff09\nimmutableList.add(6);<\/pre>\n
\u7ec4\u5408<\/strong><\/p>\n
Lambda \u8868\u8fbe\u5f0f\u5141\u8bb8\u521b\u5efa\u548c\u7ec4\u5408\u533f\u540d\u51fd\u6570\uff0c\u4f7f\u4ee3\u7801\u66f4\u5177\u6a21\u5757\u5316\u548c\u53ef\u91cd\u7528\u6027\u3002\u901a\u8fc7\u5c06\u5e38\u7528\u64cd\u4f5c\u6253\u5305\u6210\u51fd\u6570\uff0c\u53ef\u4ee5\u8f7b\u677e\u5730\u6784\u5efa\u53ef\u6839\u636e\u9700\u8981\u7ec4\u5408\u548c\u5b9a\u5236\u7684\u590d\u6742\u5904\u7406\u903b\u8f91\u3002<\/p>\n
\/\/ \u521b\u5efa\u4e00\u4e2a\u5c06\u5143\u7d20\u6620\u5c04\u5230\u5176\u5e73\u65b9\u7684\u51fd\u6570\nFunction<Integer, Integer> square = n -> n * n;\n\n\/\/ \u4f7f\u7528\u53e6\u4e00\u4e2a\u51fd\u6570\u5bf9\u7ed3\u679c\u6c42\u548c\nFunction<Stream<Integer>, Integer> sum = stream -> stream.reduce(0, (a, b) -> a + b);\n\n\/\/ \u7ec4\u5408\u8fd9\u4e24\u4e2a\u51fd\u6570\nFunction<Stream<Integer>, Integer> sumOfSquares = sum.compose(square);<\/pre>\n
\u5b9e\u6218\u6848\u4f8b<\/strong><\/p>\n
\u4f7f\u7528 Streams \u5904\u7406\u5927\u578b\u65e5\u5fd7\u6587\u4ef6<\/strong><\/p>\n
\u4f7f\u7528 Streams\uff0c\u6211\u4eec\u53ef\u4ee5\u8f7b\u677e\u5730\u4ece\u5de8\u5927\u7684\u65e5\u5fd7\u6587\u4ef6\u4e2d\u63d0\u53d6\u6709\u610f\u4e49\u7684\u4fe1\u606f\u3002\u4f8b\u5982\uff0c\u8ba1\u7b97\u4e0d\u540c IP \u5730\u5740\u51fa\u73b0\u7684\u6b21\u6570\uff1a<\/p>\n
\/\/ \u5c06\u65e5\u5fd7\u6587\u4ef6\u52a0\u8f7d\u5230 Stream \u4e2d\nStream<String> logLines = Files.lines(Paths.get(\"logs.txt\"));\n\n\/\/ \u6839\u636e IP \u5730\u5740\u5bf9\u884c\u8fdb\u884c\u5206\u7ec4\nMap<String, Long> ipCounts = logLines\n        .map(line -> line.split(\" \")[0])  \/\/ \u63d0\u53d6 IP \u5730\u5740\n        .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));<\/pre>\n
\u7ed3\u8bba<\/strong><\/p>\n
Java \u51fd\u6570\u5f0f\u7f16\u7a0b\u4e3a\u89e3\u51b3\u6570\u636e\u5904\u7406\u75db\u70b9\u63d0\u4f9b\u4e86\u5f3a\u5927\u7684\u5de5\u5177\u3002\u901a\u8fc7\u91c7\u7528\u6d41\u5904\u7406\u3001\u4e0d\u53ef\u53d8\u6027\u3001\u7ec4\u5408\u548c lambda \u8868\u8fbe\u5f0f\u7b49\u539f\u5219\uff0c\u5f00\u53d1\u8005\u53ef\u4ee5\u7f16\u5199\u66f4\u7b80\u6d01\u3001\u66f4\u5065\u58ee\u4e14\u66f4\u53ef\u7ef4\u62a4\u7684\u4ee3\u7801\uff0c\u4ece\u800c\u63d0\u9ad8\u5904\u7406\u5927\u91cf\u6570\u636e\u7684\u6548\u7387\u548c\u51c6\u786e\u6027\u3002<\/p>\n
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\u4f7f\u7528Java\u51fd\u6570\u5f0f\u7f16\u7a0b\u89e3\u51b3\u6570\u636e\u5904...<\/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-202930","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202930","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=202930"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202930\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=202930"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=202930"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=202930"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}