{"id":202656,"date":"2025-05-22T10:41:21","date_gmt":"2025-05-22T02:41:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/202656\/"},"modified":"2025-05-22T10:41:21","modified_gmt":"2025-05-22T02:41:21","slug":"java%e5%87%bd%e6%95%b0%e5%bc%8f%e6%8e%a5%e5%8f%a3%e4%b8%8epredicate%e5%87%bd%e6%95%b0%e5%bc%8f%e6%8e%a5%e5%8f%a3","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/202656\/","title":{"rendered":"Java\u51fd\u6570\u5f0f\u63a5\u53e3\u4e0ePredicate\u51fd\u6570\u5f0f\u63a5\u53e3"},"content":{"rendered":"

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

Java\u51fd\u6570\u5f0f\u63a5\u53e3\u4e0ePredicate\u51fd\u6570\u5f0f\u63a5\u53e3<\/h1>\n

\u5c0f\u4f19\u4f34\u4eec\u6709\u6ca1\u6709\u89c9\u5f97\u5b66\u4e60\u6587\u7ae0<\/span>\u5f88\u6709\u610f\u601d\uff1f\u6709\u610f\u601d\u5c31\u5bf9\u4e86\uff01\u4eca\u5929\u5c31\u7ed9\u5927\u5bb6\u5e26\u6765\u300aJava\u51fd\u6570\u5f0f\u63a5\u53e3\u4e0ePredicate\u51fd\u6570\u5f0f\u63a5\u53e3\u300b<\/span>\uff0c\u4ee5\u4e0b\u5185\u5bb9\u5c06\u4f1a\u6d89\u53ca\u5230<\/span>\uff0c\u82e5\u662f\u5728\u5b66\u4e60\u4e2d\u5bf9\u5176\u4e2d\u90e8\u5206\u77e5\u8bc6\u70b9\u6709\u7591\u95ee\uff0c\u6216\u8bb8\u770b\u4e86\u672c\u6587\u5c31\u80fd\u5e2e\u5230\u4f60\uff01<\/p>\n

Predicate \u63a5\u53e3\u662f\u51fd\u6570\u5f0f\u63a5\u53e3\uff0c\u63a5\u53d7\u4e00\u4e2a\u53c2\u6570\u5e76\u8fd4\u56de\u5e03\u5c14\u503c\u3002\u4f7f\u7528 Lambda \u8868\u8fbe\u5f0f\u53ef\u4ee5\u8f7b\u677e\u521b\u5efa Predicate \u5b9e\u4f8b\uff0c\u7528\u4e8e\u5404\u79cd\u76ee\u7684\uff0c\u4f8b\u5982\uff1a\u8fc7\u6ee4\u96c6\u5408\u9a8c\u8bc1\u8f93\u5165\u8fc7\u6ee4\u7b26\u5408\u7279\u5b9a\u6807\u51c6\u7684\u9879\u76ee\uff08\u4f8b\u5982\uff0c\u8fc7\u6ee4\u8d85\u8fc7\u6307\u5b9a\u4ef7\u683c\u7684\u8d2d\u7269\u8f66\u5546\u54c1\uff09<\/p>\n

<\/p>\n

Java \u51fd\u6570\u5f0f\u63a5\u53e3\u4e0e Predicate \u51fd\u6570\u5f0f\u63a5\u53e3<\/strong><\/p>\n

\u7b80\u4ecb<\/strong><\/p>\n

\u51fd\u6570\u5f0f\u63a5\u53e3\u662f\u4e00\u79cd\u4ec5\u5305\u542b\u5355\u4e2a\u62bd\u8c61\u65b9\u6cd5\u7684\u63a5\u53e3\u3002Predicate \u51fd\u6570\u5f0f\u63a5\u53e3\u662f\u4e00\u4e2a\u7279\u6b8a\u7c7b\u578b\u7684\u51fd\u6570\u5f0f\u63a5\u53e3\uff0c\u5b83\u63a5\u53d7\u4e00\u4e2a\u53c2\u6570\u5e76\u8fd4\u56de\u4e00\u4e2a\u5e03\u5c14\u503c\u3002<\/p>\n

\u521b\u5efa Predicate \u5b9e\u4f8b<\/strong><\/p>\n

\u4f7f\u7528 Lambda \u8868\u8fbe\u5f0f\u521b\u5efa Predicate \u5b9e\u4f8b\u975e\u5e38\u7b80\u5355\uff1a<\/p>\n

Predicate<Integer> isPositive = x -> x > 0;<\/pre>\n
\u4f7f\u7528 Predicate<\/strong><\/p>\n
\u53ef\u4ee5\u5c06\u8c13\u8bcd\u7528\u4e8e\u5404\u79cd\u76ee\u7684\uff0c\u4f8b\u5982\uff1a<\/p>\n
    \n
  • \n
    \u8fc7\u6ee4\u96c6\u5408\uff1a<\/p>\n
    List<Integer> numbers = List.of(1, 2, 3, -4, 5);\nPredicate<Integer> isPositive = x -> x > 0;\n\nList<Integer> positiveNumbers = numbers.stream()\n  .filter(isPositive)\n  .toList();<\/pre>\n<\/li>\n
  • \n
    \u9a8c\u8bc1\u8f93\u5165\uff1a<\/p>\n
    Predicate<String> isNotEmpty = s -> !s.isEmpty();\n\nif (isNotEmpty.test(input)) {\n  \/\/ \u4f7f\u7528\u8f93\u5165...\n}<\/pre>\n<\/li>\n<\/ul>\n
    \u5b9e\u6218\u6848\u4f8b\uff1a\u8d2d\u7269\u8f66\u8fc7\u6ee4<\/strong><\/p>\n
    \u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u8d2d\u7269\u8f66\uff0c\u5176\u4e2d\u5305\u542b\u5404\u79cd\u5546\u54c1\u3002\u6211\u4eec\u8981\u8fc7\u6ee4\u8d2d\u7269\u8f66\u4e2d\u7684\u6240\u6709\u4ef7\u683c\u8d85\u8fc7 100 \u7f8e\u5143\u7684\u5546\u54c1\u3002<\/p>\n
    class Product {\n    private String name;\n    private double price;\n\n    \/\/ getters and setters omitted for brevity\n}\n\nPredicate<Product> isExpensive = p -> p.getPrice() > 100;\n\n\/\/ \u83b7\u53d6\u8d2d\u7269\u8f66\u4e2d\u7684\u6240\u6709 expensive \u5546\u54c1\nList<Product> expensiveProducts = cart.getProducts().stream()\n    .filter(isExpensive)\n    .toList();<\/pre>\n
    \u5728\u4e0a\u9762\u7684\u793a\u4f8b\u4e2d\uff0cisExpensive<\/code> Predicate \u7528\u4e8e\u8fc7\u6ee4\u8d2d\u7269\u8f66\u4e2d\u7684\u4ef7\u683c\u8d85\u8fc7 100 \u7f8e\u5143\u7684\u5546\u54c1\uff0c\u4ece\u800c\u8f7b\u677e\u5730\u83b7\u53d6\u9700\u8981\u8fdb\u4e00\u6b65\u5904\u7406\u7684 expensive \u5546\u54c1\u5217\u8868\u3002<\/p>\n
    \u4ee5\u4e0a\u5c31\u662f\u672c\u6587\u7684\u5168\u90e8\u5185\u5bb9\u4e86\uff0c\u662f\u5426\u6709\u987a\u5229\u5e2e\u52a9\u4f60\u89e3\u51b3\u95ee\u9898\uff1f\u82e5\u662f\u80fd\u7ed9\u4f60\u5e26\u6765\u5b66\u4e60\u4e0a\u7684\u5e2e\u52a9\uff0c\u8bf7\u5927\u5bb6\u591a\u591a\u652f\u6301\uff01\u66f4\u591a\u5173\u4e8e\u6587\u7ae0\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u4e5f\u53ef\u5173\u6ce8\u516c\u4f17\u53f7\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
    Java\u51fd\u6570\u5f0f\u63a5\u53e3\u4e0ePredic...<\/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-202656","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202656","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=202656"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202656\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=202656"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=202656"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=202656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}