{"id":202826,"date":"2025-05-22T08:40:08","date_gmt":"2025-05-22T00:40:08","guid":{"rendered":"https:\/\/server.hk\/cnblog\/202826\/"},"modified":"2025-05-22T08:40:08","modified_gmt":"2025-05-22T00:40:08","slug":"%e7%94%a8-java-%e7%9a%84-api-%e5%92%8c%e5%ba%93%e5%ae%9e%e7%8e%b0%e5%87%bd%e6%95%b0%e5%bc%8f%e7%bc%96%e7%a8%8b","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/202826\/","title":{"rendered":"\u7528 Java \u7684 API \u548c\u5e93\u5b9e\u73b0\u51fd\u6570\u5f0f\u7f16\u7a0b"},"content":{"rendered":"<p><b><\/b>     <\/p>\n<h1>\u7528 Java \u7684 API \u548c\u5e93\u5b9e\u73b0\u51fd\u6570\u5f0f\u7f16\u7a0b<\/h1>\n<p>\u54c8\u55bd\uff01\u5927\u5bb6\u597d\uff0c\u5f88\u9ad8\u5174\u53c8\u89c1\u9762\u4e86\uff0c\u6211\u662f\u7684\u4e00\u540d\u4f5c\u8005\uff0c\u4eca\u5929\u7531\u6211\u7ed9\u5927\u5bb6\u5e26\u6765\u4e00\u7bc7<span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\">\u300a\u7528 Java \u7684 API \u548c\u5e93\u5b9e\u73b0\u51fd\u6570\u5f0f\u7f16\u7a0b\u300b<\/span>\uff0c\u672c\u6587\u4e3b\u8981\u4f1a\u8bb2\u5230<span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\"><\/span>\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5e0c\u671b\u5927\u5bb6\u4e00\u8d77\u5b66\u4e60\u8fdb\u6b65\uff0c\u4e5f\u6b22\u8fce\u5927\u5bb6\u5173\u6ce8\u3001\u70b9\u8d5e\u3001\u6536\u85cf\u3001\u8f6c\u53d1! \u4e0b\u9762\u5c31\u4e00\u8d77\u6765\u770b\u770b\u5427\uff01<\/p>\n<p>Java \u901a\u8fc7\u51fd\u6570\u63a5\u53e3\u3001\u6d41\u3001lambda \u8868\u8fbe\u5f0f\u548c\u65b9\u6cd5\u5f15\u7528\u5b9e\u73b0\u51fd\u6570\u5f0f\u7f16\u7a0b\uff1a\u51fd\u6570\u63a5\u53e3\u5b9a\u4e49\u5177\u6709\u5355\u4e2a\u62bd\u8c61\u65b9\u6cd5\u7684\u63a5\u53e3\uff0c\u53ef\u4ee5\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u884c\u4e3a\u3002\u6d41\u5141\u8bb8\u4ee5\u51fd\u6570\u5f0f\u65b9\u5f0f\u5bf9\u6570\u636e\u8fdb\u884c\u8f6c\u6362\u3001\u8fc7\u6ee4\u548c\u805a\u5408\u3002lambda \u8868\u8fbe\u5f0f\u521b\u5efa\u533f\u540d\u51fd\u6570\uff0c\u53ef\u4ee5\u50cf\u53d8\u91cf\u4e00\u6837\u4f20\u9012\u548c\u8d4b\u503c\u3002\u65b9\u6cd5\u5f15\u7528\u63d0\u4f9b\u7b80\u6d01\u7684\u65b9\u6cd5\u6765\u5f15\u7528\u73b0\u6709\u65b9\u6cd5\u3002\u901a\u8fc7\u8fd9\u4e9b\u7279\u6027\uff0c\u51fd\u6570\u5f0f\u7f16\u7a0b\u53ef\u4ee5\u5728 Java \u4e2d\u5b9e\u73b0\uff0c\u7528\u4e8e\u6570\u636e\u5904\u7406\u548c\u8ba1\u7b97\uff0c\u5982\u6587\u4ef6\u4e2d\u7684\u5355\u8bcd\u8ba1\u6570\u548c\u6309\u9891\u7387\u6392\u5e8f\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241026\/1729946613671ce3f5ee6ab.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>\u4f7f\u7528 Java \u5b9e\u73b0\u51fd\u6570\u5f0f\u7f16\u7a0b<\/strong><\/p>\n<p>\u51fd\u6570\u5f0f\u7f16\u7a0b\u8303\u5f0f\u5f3a\u8c03\u4f7f\u7528\u4e0d\u53ef\u53d8\u503c\u3001\u7eaf\u51fd\u6570\u548c\u9ad8\u9636\u51fd\u6570\u6765\u64cd\u4f5c\u6570\u636e\u3002Java \u867d\u7136\u4e3b\u8981\u662f\u4e00\u4e2a\u9762\u5411\u5bf9\u8c61\u7684\u8bed\u8a00\uff0c\u4f46\u5b83\u63d0\u4f9b\u4e86\u901a\u8fc7\u5176 API \u548c\u5e93\u5b9e\u73b0\u51fd\u6570\u5f0f\u7f16\u7a0b\u7684\u7279\u6027\u3002<\/p>\n<p><strong>\u51fd\u6570\u63a5\u53e3<\/strong><\/p>\n<p>\u51fd\u6570\u63a5\u53e3\u662f\u4e00\u4e2a\u5177\u6709\u5355\u4e2a\u62bd\u8c61\u65b9\u6cd5\u7684\u63a5\u53e3\u3002\u5b83\u4eec\u5141\u8bb8\u5c06\u884c\u4e3a\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u7ed9\u5176\u4ed6\u65b9\u6cd5\uff0c\u4ee5\u5b9e\u73b0\u6570\u636e\u8f6c\u6362\u548c\u8ba1\u7b97\u3002Java \u4e2d\u5e38\u7528\u7684\u51fd\u6570\u63a5\u53e3\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><code>java.util.function.Function&lt;T, R&gt;<\/code>\uff1a\u5c06\u7c7b\u578b <code>T<\/code> \u7684\u8f93\u5165\u8f6c\u6362\u4e3a\u7c7b\u578b <code>R<\/code> \u8f93\u51fa\u7684\u51fd\u6570\u3002<\/li>\n<li><code>java.util.function.Consumer&lt;T&gt;<\/code>\uff1a\u4e0d\u8fd4\u56de\u7ed3\u679c\u7684\u7c7b\u578b <code>T<\/code> \u7684\u6d88\u8d39\u8005\u3002<\/li>\n<li><code>java.util.function.Predicate&lt;T&gt;<\/code>\uff1a\u6839\u636e\u5e03\u5c14\u6761\u4ef6\u5bf9\u7c7b\u578b <code>T<\/code> \u7684\u8f93\u5165\u8fdb\u884c\u6c42\u503c\u7684\u8c13\u8bcd\u3002<\/li>\n<\/ul>\n<p><strong>\u6d41<\/strong><\/p>\n<p>\u6d41\u662f\u6570\u636e\u5143\u7d20\u7684\u987a\u5e8f\u5e8f\u5217\uff0c\u53ef\u901a\u8fc7\u4e00\u7cfb\u5217\u4e2d\u95f4\u64cd\u4f5c\u8fdb\u884c\u5904\u7406\u3002Java 8 \u4e2d\u7684\u6d41 API \u5141\u8bb8\u4f7f\u7528\u51fd\u6570\u5f0f\u7f16\u7a0b\u98ce\u683c\u5bf9\u6570\u636e\u8fdb\u884c\u8f6c\u6362\u3001\u8fc7\u6ee4\u548c\u805a\u5408\uff1a<\/p>\n<pre>List&lt;Integer&gt; numbers = List.of(1, 2, 3, 4, 5);\n\n\/\/ \u8fc7\u6ee4\u51fa\u5076\u6570\nList&lt;Integer&gt; evenNumbers = numbers.stream()\n                                  .filter(n -&gt; n % 2 == 0)\n                                  .toList();\n\n\/\/ \u805a\u5408\u6c42\u548c\nint sum = numbers.stream()\n                 .reduce(0, (a, b) -&gt; a + b);<\/pre>\n<p><strong>Lambda \u8868\u8fbe\u5f0f\u548c\u65b9\u6cd5\u5f15\u7528<\/strong><\/p>\n<p>Lambda \u8868\u8fbe\u5f0f\u5141\u8bb8\u521b\u5efa\u533f\u540d\u51fd\u6570\uff0c\u53ef\u4ee5\u50cf\u53d8\u91cf\u4e00\u6837\u4f20\u9012\u548c\u8d4b\u503c\uff1a<\/p>\n<pre>\/\/ \u58f0\u660e\u4e00\u4e2a\u63a5\u6536\u6574\u6570\u5e76\u8fd4\u56de\u5176\u5e73\u65b9\u7684 Lambda \u8868\u8fbe\u5f0f\nFunction&lt;Integer, Integer&gt; square = n -&gt; n * n;<\/pre>\n<p>\u65b9\u6cd5\u5f15\u7528\u63d0\u4f9b\u4e86\u4e00\u79cd\u66f4\u7b80\u6d01\u7684\u65b9\u5f0f\u6765\u5f15\u7528\u73b0\u6709\u65b9\u6cd5\uff1a<\/p>\n<pre>\/\/ \u58f0\u660e\u4e00\u4e2a\u63a5\u6536\u6574\u6570\u5e76\u8fd4\u56de\u5176\u7edd\u5bf9\u503c\u7684 Lambda \u8868\u8fbe\u5f0f\nFunction&lt;Integer, Integer&gt; abs = Math::abs;<\/pre>\n<p><strong>\u5b9e\u6218\u6848\u4f8b<\/strong><\/p>\n<p>\u8003\u8651\u4e00\u4e2a\u9700\u8981\u5c06\u6587\u4ef6\u4e2d\u7684\u5355\u8bcd\u8ba1\u6570\u5e76\u6309\u9891\u7387\u6392\u5e8f\u7684\u7a0b\u5e8f\u3002\u4f7f\u7528\u51fd\u6570\u5f0f\u7f16\u7a0b\uff0c\u6211\u4eec\u53ef\u4ee5\u5c06\u6b64\u95ee\u9898\u5206\u89e3\u4e3a\u4e00\u7cfb\u5217\u53ef\u91cd\u7528\u7684\u6b65\u9aa4\uff1a<\/p>\n<pre>import java.io.IOException;\nimport java.nio.file.Files;\nimport java.nio.file.Paths;\nimport java.util.*;\n\npublic class WordCounter {\n\n    public static void main(String[] args) throws IOException {\n        \/\/ \u8bfb\u53d6\u6587\u4ef6\u4e2d\u7684\u6240\u6709\u5355\u8bcd\n        List&lt;String&gt; words = Files.readAllLines(Paths.get(\"file.txt\"))\n                                 .stream()\n                                 .flatMap(line -&gt; Arrays.stream(line.split(\" \")))\n                                 .toList();\n\n        \/\/ \u7edf\u8ba1\u6bcf\u4e2a\u5355\u8bcd\u7684\u51fa\u73b0\u6b21\u6570\n        Map&lt;String, Integer&gt; wordCounts = words.stream()\n                                              .collect(Collectors.groupingBy(Function.identity(), Collectors.summingInt(i -&gt; 1)));\n\n        \/\/ \u6309\u51fa\u73b0\u6b21\u6570\u964d\u5e8f\u6392\u5e8f\n        List&lt;Map.Entry&lt;String, Integer&gt;&gt; sortedCounts = wordCounts.entrySet().stream()\n                                                                    .sorted(Comparator.comparing(Map.Entry::getValue).reversed())\n                                                                    .toList();\n\n        \/\/ \u6253\u5370\u7ed3\u679c\n        for (Map.Entry&lt;String, Integer&gt; entry : sortedCounts) {\n            System.out.println(entry.getKey() + \": \" + entry.getValue());\n        }\n    }\n}<\/pre>\n<p>\u7ec8\u4e8e\u4ecb\u7ecd\u5b8c\u5566\uff01\u5c0f\u4f19\u4f34\u4eec\uff0c\u8fd9\u7bc7\u5173\u4e8e\u300a\u7528 Java \u7684 API \u548c\u5e93\u5b9e\u73b0\u51fd\u6570\u5f0f\u7f16\u7a0b\u300b\u7684\u4ecb\u7ecd\u5e94\u8be5\u8ba9\u4f60\u6536\u83b7\u591a\u591a\u4e86\u5427\uff01\u6b22\u8fce\u5927\u5bb6\u6536\u85cf\u6216\u5206\u4eab\u7ed9\u66f4\u591a\u9700\u8981\u5b66\u4e60\u7684\u670b\u53cb\u5427~\u516c\u4f17\u53f7\u4e5f\u4f1a\u53d1\u5e03\u6587\u7ae0\u76f8\u5173\u77e5\u8bc6\uff0c\u5feb\u6765\u5173\u6ce8\u5427\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u7528 Java \u7684 API \u548c\u5e93\u5b9e&#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-202826","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202826","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=202826"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202826\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=202826"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=202826"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=202826"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}