{"id":1752,"date":"2023-03-26T21:29:00","date_gmt":"2023-03-26T13:29:00","guid":{"rendered":"https:\/\/www.appblog.cn\/?p=1752"},"modified":"2023-04-23T21:27:20","modified_gmt":"2023-04-23T13:27:20","slug":"java-8-consumer-supplier-predict-and-function","status":"publish","type":"post","link":"https:\/\/www.appblog.cn\/index.php\/2023\/03\/26\/java-8-consumer-supplier-predict-and-function\/","title":{"rendered":"Java 8\u7684\u4e2dConsumer\u3001Supplier\u3001Predicate\u548cFunction"},"content":{"rendered":"

\u8fd9\u51e0\u4e2a\u63a5\u53e3\u90fd\u5728java.util.function<\/code>\u5305\u4e0b\u7684\uff0c\u5206\u522b\u662fConsumer\uff08\u6d88\u8d39\u578b\uff09\u3001supplier\uff08\u4f9b\u7ed9\u578b\uff09\u3001predicate\uff08\u8c13\u8bcd\u578b\uff09\u3001function\uff08\u529f\u80fd\u6027\uff09<\/p>\n

Consumer\u63a5\u53e3<\/h2>\n

\u4ece\u5b57\u9762\u4e0a\u770b\uff0cConsumer\u63a5\u53e3\u5c31\u662f\u4e00\u4e2a\u6d88\u8d39\u578b\u7684\u63a5\u53e3\uff0c\u901a\u8fc7\u4f20\u5165\u53c2\u6570\uff0c\u7136\u540e\u8f93\u51fa\u503c\uff0c\u5c31\u662f\u8fd9\u4e48\u7b80\u5355<\/p>\n

<\/p>\n

Consumer\u5b9e\u4f8b<\/h3>\n
\/**\n * consumer\u63a5\u53e3\u6d4b\u8bd5\n *\/\n@Test\npublic void testConsumer() {\n    \/\/\u2460 \u4f7f\u7528consumer\u63a5\u53e3\u5b9e\u73b0\u65b9\u6cd5\n    Consumer<String> consumer = new Consumer<String>() {\n\n        @Override\n        public void accept(String s) {\n            System.out.println(s);\n        }\n    };\n    Stream<String> stream = Stream.of("aaa", "bbb", "ccc");\n    stream.forEach(consumer);\n\n    System.out.println("********************");\n\n    \/\/\u2461 \u4f7f\u7528lambda\u8868\u8fbe\u5f0f\uff0cforEach\u65b9\u6cd5\u9700\u8981\u7684\u5c31\u662f\u4e00\u4e2aConsumer\u63a5\u53e3\n    stream = Stream.of("aaa", "bbb", "ccc");\n    Consumer<String> consumer1 = (s) -> System.out.println(s); \/\/lambda\u8868\u8fbe\u5f0f\u8fd4\u56de\u7684\u5c31\u662f\u4e00\u4e2aConsumer\u63a5\u53e3\n    stream.forEach(consumer1);\n    \/\/\u66f4\u76f4\u63a5\u7684\u65b9\u5f0f\n    \/\/stream.forEach((s) -> System.out.println(s));\n    System.out.println("********************");\n\n    \/\/\u2462 \u4f7f\u7528\u65b9\u6cd5\u5f15\u7528\uff0c\u65b9\u6cd5\u5f15\u7528\u4e5f\u662f\u4e00\u4e2aconsumer\n    stream = Stream.of("aaa", "bbb", "ccc");\n    Consumer consumer2 = System.out::println;\n    stream.forEach(consumer);\n    \/\/\u66f4\u76f4\u63a5\u7684\u65b9\u5f0f\n    \/\/stream.forEach(System.out::println);\n}<\/code><\/pre>\n
\u8f93\u51fa\u7ed3\u679c<\/p>\n
aaa\nbbb\nccc\n********************\naaa\nbbb\nccc\n********************\naaa\nbbb\nccc<\/code><\/pre>\n
\u5b9e\u4f8b\u5206\u6790<\/h3>\n
\u2460 Consumer<\/code>\u63a5\u53e3\u5206\u6790<\/p>\n
\u5728\u4ee3\u7801\u2460\u4e2d\uff0c\u6211\u4eec\u76f4\u63a5\u521b\u5efaConsumer<\/code>\u63a5\u53e3\uff0c\u5e76\u4e14\u5b9e\u73b0\u4e86\u4e00\u4e2a\u540d\u4e3aaccept<\/code>\u7684\u65b9\u6cd5\uff0c\u8fd9\u4e2a\u65b9\u6cd5\u5c31\u662f\u8fd9\u4e2a\u63a5\u53e3\u7684\u5173\u952e\u4e86\u3002<\/p>\n
\u6211\u4eec\u770b\u4e00\u4e0baccept<\/code>\u65b9\u6cd5\uff1b\u8fd9\u4e2a\u65b9\u6cd5\u4f20\u5165\u4e00\u4e2a\u53c2\u6570\uff0c\u4e0d\u8fd4\u56de\u503c\u3002\u5f53\u6211\u4eec\u53d1\u73b0forEach<\/code>\u9700\u8981\u4e00\u4e2aConsumer<\/code>\u7c7b\u578b\u7684\u53c2\u6570\u7684\u65f6\u5019\uff0c\u4f20\u5165\u4e4b\u540e\uff0c\u5c31\u53ef\u4ee5\u8f93\u51fa\u5bf9\u5e94\u7684\u503c\u4e86\u3002<\/p>\n
\u2461 lambda<\/code>\u8868\u8fbe\u5f0f\u4f5c\u4e3aConsumer<\/code><\/p>\n
Consumer<String> consumer1 = (s) -> System.out.println(s); \/\/lambda\u8868\u8fbe\u5f0f\u8fd4\u56de\u7684\u5c31\u662f\u4e00\u4e2aConsumer\u63a5\u53e3<\/code><\/pre>\n
\u5728\u4e0a\u9762\u7684\u4ee3\u7801\u4e2d\uff0c\u6211\u4eec\u4f7f\u7528\u4e0b\u9762\u7684lambda<\/code>\u8868\u8fbe\u5f0f\u4f5c\u4e3aConsumer<\/code>\u3002\u4ed4\u7ec6\u7684\u770b\u4e00\u4e0b\u4f1a\u53d1\u73b0\uff0clambda<\/code>\u8868\u8fbe\u5f0f\u8fd4\u56de\u503c\u5c31\u662f\u4e00\u4e2aConsumer<\/code>\uff1b\u6240\u4ee5\uff0c\u4e5f\u5c31\u80fd\u591f\u7406\u89e3\u4e3a\u4ec0\u4e48forEach<\/code>\u65b9\u6cd5\u53ef\u4ee5\u4f7f\u7528lamdda<\/code>\u8868\u8fbe\u5f0f\u4f5c\u4e3a\u53c2\u6570\u4e86\u5427\u3002<\/p>\n
\u2462 \u65b9\u6cd5\u5f15\u7528\u4f5c\u4e3aConsumer<\/code><\/p>\n
Consumer consumer2 = System.out::println;<\/code><\/pre>\n
\u5728\u4e0a\u9762\u7684\u4ee3\u7801\u4e2d\uff0c\u6211\u4eec\u7528\u4e86\u4e00\u4e2a\u65b9\u6cd5\u5f15\u7528\u7684\u65b9\u5f0f\u4f5c\u4e3a\u4e00\u4e2aConsumer<\/code>\uff0c\u540c\u65f6\u4e5f\u53ef\u4ee5\u4f20\u7ed9forEach<\/code>\u65b9\u6cd5\u3002<\/p>\n
\u5176\u4ed6Consumer<\/code>\u63a5\u53e3<\/h3>\n
\u9664\u4e86\u4e0a\u9762\u4f7f\u7528\u7684Consumer<\/code>\u63a5\u53e3\uff0c\u8fd8\u53ef\u4ee5\u4f7f\u7528\u4e0b\u9762\u8fd9\u4e9bConsumer<\/code>\u63a5\u53e3\u3002
\nIntConsumer<\/code>\u3001DoubleConsumer<\/code>\u3001LongConsumer<\/code>\u3001BiConsumer<\/code>\uff0c\u4f7f\u7528\u65b9\u6cd5\u548c\u4e0a\u9762\u4e00\u6837\u3002<\/p>\n
Consumer \u603b\u7ed3<\/h3>\n
\u770b\u5b8c\u4e0a\u9762\u7684\u5b9e\u4f8b\u6211\u4eec\u53ef\u4ee5\u603b\u7ed3\u4e3a\u51e0\u70b9\u3002<\/p>\n
\u2460 Consumer<\/code>\u662f\u4e00\u4e2a\u63a5\u53e3\uff0c\u5e76\u4e14\u53ea\u8981\u5b9e\u73b0\u4e00\u4e2aaccept<\/code>\u65b9\u6cd5\uff0c\u5c31\u53ef\u4ee5\u4f5c\u4e3a\u4e00\u4e2a\u201c\u6d88\u8d39\u8005\u201d\u8f93\u51fa\u4fe1\u606f\u3002
\n\u2461 \u5176\u5b9e\uff0clambda<\/code>\u8868\u8fbe\u5f0f\u3001\u65b9\u6cd5\u5f15\u7528\u7684\u8fd4\u56de\u503c\u90fd\u662fConsumer<\/code>\u7c7b\u578b\uff0c\u6240\u4ee5\uff0c\u4ed6\u4eec\u80fd\u591f\u4f5c\u4e3aforEach<\/code>\u65b9\u6cd5\u7684\u53c2\u6570\uff0c\u5e76\u4e14\u8f93\u51fa\u4e00\u4e2a\u503c\u3002<\/p>\n
Supplier \u63a5\u53e3<\/h2>\n
Supplier<\/code>\u63a5\u53e3\u662f\u4e00\u4e2a\u4f9b\u7ed9\u578b\u7684\u63a5\u53e3\uff0c\u5176\u5b9e\uff0c\u8bf4\u767d\u4e86\u5c31\u662f\u4e00\u4e2a\u5bb9\u5668\uff0c\u53ef\u4ee5\u7528\u6765\u5b58\u50a8\u6570\u636e\uff0c\u7136\u540e\u53ef\u4ee5\u4f9b\u5176\u4ed6\u65b9\u6cd5\u4f7f\u7528\u7684\u8fd9\u4e48\u4e00\u4e2a\u63a5\u53e3\u3002<\/p>\n
Supplier\u5b9e\u4f8b<\/h3>\n
**\n * Supplier\u63a5\u53e3\u6d4b\u8bd5\uff0csupplier\u76f8\u5f53\u4e00\u4e2a\u5bb9\u5668\u6216\u8005\u53d8\u91cf\uff0c\u53ef\u4ee5\u5b58\u50a8\u503c\n *\/\n@Test\npublic void testSupplier() {\n    \/\/\u2460 \u4f7f\u7528Supplier\u63a5\u53e3\u5b9e\u73b0\u65b9\u6cd5\uff0c\u53ea\u6709\u4e00\u4e2aget\u65b9\u6cd5\uff0c\u65e0\u53c2\u6570\uff0c\u8fd4\u56de\u4e00\u4e2a\u503c\n    Supplier<Integer> supplier = new Supplier<Integer>() {\n        @Override\n        public Integer get() {\n            \/\/\u8fd4\u56de\u4e00\u4e2a\u968f\u673a\u503c\n            return new Random().nextInt();\n        }\n    };\n\n    System.out.println(supplier.get());\n    System.out.println("********************");\n\n    \/\/\u2461 \u4f7f\u7528lambda\u8868\u8fbe\u5f0f\n    supplier = () -> new Random().nextInt();\n    System.out.println(supplier.get());\n    System.out.println("********************");\n\n    \/\/\u2462 \u4f7f\u7528\u65b9\u6cd5\u5f15\u7528\n    Supplier<Double> supplier2 = Math::random;\n    System.out.println(supplier2.get());\n}<\/code><\/pre>\n
\u8f93\u51fa\u7ed3\u679c<\/p>\n
-19080692\n********************\n278389927\n********************\n0.99785060190326665<\/code><\/pre>\n
\u5b9e\u4f8b\u5206\u6790<\/h3>\n
\u2460 Supplier\u63a5\u53e3\u5206\u6790<\/p>\n
Supplier<Integer> supplier = new Supplier<Integer>() {\n    @Override\n    public Integer get() {\n        \/\/\u8fd4\u56de\u4e00\u4e2a\u968f\u673a\u503c\n        return new Random().nextInt();\n    }\n};<\/code><\/pre>\n
\u770b\u4e00\u4e0b\u8fd9\u6bb5\u4ee3\u7801\uff0c\u6211\u4eec\u901a\u8fc7\u521b\u5efa\u4e00\u4e2aSupplier<\/code>\u5bf9\u8c61\uff0c\u5b9e\u73b0\u4e86\u4e00\u4e2aget<\/code>\u65b9\u6cd5\uff0c\u8fd9\u4e2a\u65b9\u6cd5\u65e0\u53c2\u6570\uff0c\u8fd4\u56de\u4e00\u4e2a\u503c\uff1b\u6240\u4ee5\uff0c\u6bcf\u6b21\u4f7f\u7528\u8fd9\u4e2a\u63a5\u53e3\u7684\u65f6\u5019\u90fd\u4f1a\u8fd4\u56de\u4e00\u4e2a\u503c\uff0c\u5e76\u4e14\u4fdd\u5b58\u5728\u8fd9\u4e2a\u63a5\u53e3\u4e2d\uff0c\u6240\u4ee5\u8bf4\u662f\u4e00\u4e2a\u5bb9\u5668\u3002<\/p>\n
\u2461 lambda<\/code>\u8868\u8fbe\u5f0f\u4f5c\u4e3aSupplier<\/code><\/p>\n
\/\/\u2461 \u4f7f\u7528lambda\u8868\u8fbe\u5f0f\uff0c\nsupplier = () -> new Random().nextInt();\nSystem.out.println(supplier.get());\nSystem.out.println("********************");<\/code><\/pre>\n
\u4e0a\u9762\u7684\u8fd9\u6bb5\u4ee3\u7801\uff0c\u6211\u4eec\u4f7f\u7528lambda<\/code>\u8868\u8fbe\u5f0f\u8fd4\u56de\u4e00\u4e2aSupplier<\/code>\u7c7b\u578b\u7684\u63a5\u53e3\uff0c\u7136\u540e\uff0c\u6211\u4eec\u8c03\u7528get<\/code>\u65b9\u6cd5\u5373\u53ef\u83b7\u53d6\u8fd9\u4e2a\u503c\u3002<\/p>\n
\u2462 \u65b9\u6cd5\u5f15\u7528\u4f5c\u4e3a Supplier<\/p>\n
\/\/\u2462 \u4f7f\u7528\u65b9\u6cd5\u5f15\u7528\nSupplier<Double> supplier2 = Math::random;\nSystem.out.println(supplier2.get());<\/code><\/pre>\n
\u65b9\u6cd5\u5f15\u7528\u4e5f\u662f\u8fd4\u56de\u4e00\u4e2aSupplier<\/code>\u7c7b\u578b\u7684\u63a5\u53e3\u3002<\/p>\n
Supplier \u5b9e\u4f8b2<\/h3>\n
\u6211\u4eec\u770b\u5b8c\u7b2c\u4e00\u4e2a\u5b9e\u4f8b\u4e4b\u540e\uff0c\u5e94\u8be5\u6709\u4e00\u4e2a\u4e86\u89e3\u4e86\uff0c\u4e0b\u9762\u518d\u770b\u4e00\u4e2a\u3002<\/p>\n
\/**\n * Supplier\u63a5\u53e3\u6d4b\u8bd52\uff0c\u4f7f\u7528\u9700\u8981Supplier\u7684\u63a5\u53e3\u65b9\u6cd5\n *\/\n@Test\npublic void testSupplier2() {\n    Stream<Integer> stream = Stream.of(1, 2, 3, 4, 5);\n    \/\/\u8fd4\u56de\u4e00\u4e2aoptional\u5bf9\u8c61\n    Optional<Integer> first = stream.filter(i -> i > 4)\n            .findFirst();\n\n    \/\/optional\uff0c\u5bf9\u8c61\u6709\u9700\u8981Supplier\u63a5\u53e3\u7684\u65b9\u6cd5\n    \/\/orElse\uff0c\u5982\u679cfirst\u4e2d\u5b58\u5728\u6570\uff0c\u5c31\u8fd4\u56de\u8fd9\u4e2a\u6570\uff0c\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u5c31\u653e\u56de\u4f20\u5165\u7684\u6570\n    System.out.println(first.orElse(1));\n    System.out.println(first.orElse(7));\n\n    System.out.println("********************");\n\n    Supplier<Integer> supplier = new Supplier<Integer>() {\n        @Override\n        public Integer get() {\n            \/\/\u8fd4\u56de\u4e00\u4e2a\u968f\u673a\u503c\n            return new Random().nextInt();\n        }\n    };\n\n    \/\/orElseGet\uff0c\u5982\u679cfirst\u4e2d\u5b58\u5728\u6570\uff0c\u5c31\u8fd4\u56de\u8fd9\u4e2a\u6570\uff0c\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u5c31\u8fd4\u56desupplier\u8fd4\u56de\u7684\u503c\n    System.out.println(first.orElseGet(supplier));\n}<\/code><\/pre>\n
\u8f93\u51fa\u7ed3\u679c<\/p>\n
5\n5\n********************\n5<\/code><\/pre>\n
\u4ee3\u7801\u5206\u6790<\/p>\n
Optional<Integer> first = stream.filter(i -> i > 4)\n                .findFirst();<\/code><\/pre>\n
\u4f7f\u7528\u8fd9\u4e2a\u65b9\u6cd5\u83b7\u53d6\u5230\u4e00\u4e2aOptional<\/code>\u5bf9\u8c61\uff0c\u5728Optional<\/code>\u5bf9\u8c61\u4e2d\u6709orElse<\/code>\u65b9\u6cd5 \u548corElseGet<\/code>\u662f\u9700\u8981\u4e00\u4e2aSupplier<\/code>\u63a5\u53e3\u7684\u3002<\/p>\n
    \n
  • orElse<\/code>\uff1a\u5982\u679cfirst\u4e2d\u5b58\u5728\u6570\uff0c\u5c31\u8fd4\u56de\u8fd9\u4e2a\u6570\uff0c\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u5c31\u653e\u56de\u4f20\u5165\u7684\u6570<\/li>\n
  • orElseGet<\/code>\uff1a\u5982\u679cfirst\u4e2d\u5b58\u5728\u6570\uff0c\u5c31\u8fd4\u56de\u8fd9\u4e2a\u6570\uff0c\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u5c31\u8fd4\u56desupplier\u8fd4\u56de\u7684\u503c<\/li>\n<\/ul>\n
    \u5176\u4ed6 Supplier \u63a5\u53e3<\/h3>\n
    \u9664\u4e86\u4e0a\u9762\u4f7f\u7528\u7684Supplier<\/code>\u63a5\u53e3\uff0c\u8fd8\u53ef\u4ee5\u4f7f\u7528\u4e0b\u9762\u8fd9\u4e9bSupplier<\/code>\u63a5\u53e3\u3002
    \nIntSupplier<\/code>\u3001DoubleSupplier<\/code>\u3001LongSupplier<\/code>\u3001BooleanSupplier<\/code>\uff0c\u4f7f\u7528\u65b9\u6cd5\u548c\u4e0a\u9762\u4e00\u6837\u3002<\/p>\n
    Supplier \u603b\u7ed3<\/h3>\n
      \n
    • Supplier<\/code>\u63a5\u53e3\u53ef\u4ee5\u7406\u89e3\u4e3a\u4e00\u4e2a\u5bb9\u5668\uff0c\u7528\u4e8e\u88c5\u6570\u636e\u7684<\/li>\n
    • Supplier<\/code>\u63a5\u53e3\u6709\u4e00\u4e2aget<\/code>\u65b9\u6cd5\uff0c\u53ef\u4ee5\u8fd4\u56de\u503c<\/li>\n<\/ul>\n
      Predicate \u63a5\u53e3<\/h2>\n
      Predicate<\/code>\u63a5\u53e3\u662f\u4e00\u4e2a\u8c13\u8bcd\u578b\u63a5\u53e3\uff0c\u5176\u5b9e\uff0c\u8fd9\u5c31\u662f\u4e00\u4e2a\u7c7b\u4f3c\u4e8ebool<\/code>\u7c7b\u578b\u7684\u5224\u65ad\u63a5\u53e3\u3002<\/p>\n
      Predicate \u5b9e\u4f8b<\/h3>\n
      \/**\n * Predicate\u8c13\u8bcd\u6d4b\u8bd5\uff0c\u8c13\u8bcd\u5176\u5b9e\u5c31\u662f\u4e00\u4e2a\u5224\u65ad\u7684\u4f5c\u7528\u7c7b\u4f3cbool\u7684\u4f5c\u7528\n *\/\n@Test\npublic void testPredicate() {\n    \/\/\u2460 \u4f7f\u7528Predicate\u63a5\u53e3\u5b9e\u73b0\u65b9\u6cd5\uff0c\u53ea\u6709\u4e00\u4e2atest\u65b9\u6cd5\uff0c\u4f20\u5165\u4e00\u4e2a\u53c2\u6570\uff0c\u8fd4\u56de\u4e00\u4e2abool\u503c\n    Predicate<Integer> predicate = new Predicate<Integer>() {\n        @Override\n        public boolean test(Integer integer) {\n            if (integer > 5) {\n                return true;\n            }\n            return false;\n        }\n    };\n\n    System.out.println(predicate.test(6));\n    System.out.println("********************");\n\n    \/\/\u2461 \u4f7f\u7528lambda\u8868\u8fbe\u5f0f\n    predicate = (t) -> t > 5;\n    System.out.println(predicate.test(1));\n}<\/code><\/pre>\n
      \u8f93\u51fa\u7ed3\u679c<\/p>\n
      true\n********************\nfalse<\/code><\/pre>\n
      \u5b9e\u4f8b\u5206\u6790<\/h3>\n
      \u2460 Predicate<\/code>\u63a5\u53e3\u5206\u6790<\/p>\n
      \/\/\u2460 \u4f7f\u7528Predicate\u63a5\u53e3\u5b9e\u73b0\u65b9\u6cd5,\u53ea\u6709\u4e00\u4e2atest\u65b9\u6cd5\uff0c\u4f20\u5165\u4e00\u4e2a\u53c2\u6570\uff0c\u8fd4\u56de\u4e00\u4e2abool\u503c\nPredicate<Integer> predicate = new Predicate<Integer>() {\n    @Override\n    public boolean test(Integer integer) {\n        if (integer > 5) {\n            return true;\n        }\n        return false;\n    }\n};<\/code><\/pre>\n
      \u8fd9\u6bb5\u4ee3\u7801\u4e2d\uff0c\u521b\u5efa\u4e86\u4e00\u4e2aPredicate<\/code>\u63a5\u53e3\u5bf9\u8c61\uff0c\u5176\u4e2d\uff0c\u5b9e\u73b0\u7c7btest<\/code>\u65b9\u6cd5\uff0c\u9700\u8981\u4f20\u5165\u4e00\u4e2a\u53c2\u6570\uff0c\u5e76\u4e14\u8fd4\u56de\u4e00\u4e2abool<\/code>\u503c\uff0c\u6240\u4ee5\u8fd9\u4e2a\u63a5\u53e3\u4f5c\u7528\u5c31\u662f\u5224\u65ad\uff01<\/p>\n
      System.out.println(predicate.test(6));<\/code><\/pre>\n
      \u518d\u770b\uff0c\u8c03\u7528test<\/code>\u65b9\u6cd5\uff0c\u4f20\u5165\u4e00\u4e2a\u503c\uff0c\u5c31\u4f1a\u8fd4\u56de\u4e00\u4e2abool<\/code>\u503c\u3002<\/p>\n
      \u2461 \u4f7f\u7528lambda<\/code>\u8868\u8fbe\u5f0f\u4f5c\u4e3apredicate<\/code><\/p>\n
      \/\/\u2461 \u4f7f\u7528lambda\u8868\u8fbe\u5f0f\uff0c\npredicate = (t) -> t > 5;\nSystem.out.println(predicate.test(1));<\/code><\/pre>\n
      lambda<\/code>\u8868\u8fbe\u5f0f\u8fd4\u56de\u4e00\u4e2aPredicate<\/code>\u63a5\u53e3\uff0c\u7136\u540e\u8c03\u7528test<\/code>\u65b9\u6cd5\uff01<\/p>\n
      Predicate \u63a5\u53e3\u5b9e\u4f8b2<\/h3>\n
      \/**\n * Predicate\u8c13\u8bcd\u6d4b\u8bd5\uff0cPredicate\u4f5c\u4e3a\u63a5\u53e3\u4f7f\u7528\n *\/\n@Test\npublic void testPredicate2() {\n    \/\/\u2460 \u5c06Predicate\u4f5c\u4e3afilter\u63a5\u53e3\uff0cPredicate\u8d77\u5230\u4e00\u4e2a\u5224\u65ad\u7684\u4f5c\u7528\n    Predicate<Integer> predicate = new Predicate<Integer>() {\n        @Override\n        public boolean test(Integer integer) {\n            if (integer > 5) {\n                return true;\n            }\n            return false;\n        }\n    };\n\n    Stream<Integer> stream = Stream.of(1, 23, 3, 4, 5, 56, 6, 6);\n    List<Integer> list = stream.filter(predicate).collect(Collectors.toList());\n    list.forEach(System.out::println);\n}\n\n\u8f93\u51fa\u7ed3\u679c\n<\/code><\/pre>\n
      23
      \n56
      \n6
      \n6<\/p>\n
      \n\u8fd9\u6bb5\u4ee3\u7801\uff0c\u9996\u5148\u521b\u5efa\u4e00\u4e2a`Predicate`\u5bf9\u8c61\uff0c\u7136\u540e\u5b9e\u73b0`test`\u65b9\u6cd5\uff0c\u5728`test`\u65b9\u6cd5\u4e2d\u505a\u4e00\u4e2a\u5224\u65ad\uff1a\u5982\u679c\u4f20\u5165\u7684\u53c2\u6570\u5927\u4e8e 5 \uff0c\u5c31\u8fd4\u56de`true`\uff0c\u5426\u5219\u8fd4\u56de`false`\uff1b\n\n```java\nStream stream = Stream.of(1, 23, 3, 4, 5, 56, 6, 6);\nList list = stream.filter(predicate).collect(Collectors.toList());\nlist.forEach(System.out::println);<\/code><\/pre>\n
      \u8fd9\u6bb5\u4ee3\u7801\u8c03\u7528`Stream`\u7684`filter`\u65b9\u6cd5\uff0c`filter`\u65b9\u6cd5\u9700\u8981\u7684\u53c2\u6570\u5c31\u662f`Predicate`\u63a5\u53e3\uff0c\u6240\u4ee5\u5728\u8fd9\u91cc\u53ea\u8981\u5927\u4e8e 5 \u7684\u6570\u636e\u5c31\u4f1a\u8f93\u51fa\u3002<\/p>\n
      Predicate \u63a5\u53e3\u603b\u7ed3<\/h3>\n
        \n
      • `Predicate`\u662f\u4e00\u4e2a\u8c13\u8bcd\u578b\u63a5\u53e3\uff0c\u5176\u5b9e\u53ea\u662f\u8d77\u5230\u4e00\u4e2a\u5224\u65ad\u4f5c\u7528<\/li>\n
      • `Predicate`\u901a\u8fc7\u5b9e\u73b0\u4e00\u4e2a`test`\u65b9\u6cd5\u505a\u5224\u65ad<\/li>\n<\/ul>\n
        Function \u63a5\u53e3<\/h2>\n
        `Function`\u63a5\u53e3\u662f\u4e00\u4e2a\u529f\u80fd\u578b\u63a5\u53e3\uff0c\u5b83\u7684\u4e00\u4e2a\u4f5c\u7528\u5c31\u662f\u8f6c\u6362\u4f5c\u7528\uff0c\u5c06\u8f93\u5165\u6570\u636e\u8f6c\u6362\u6210\u53e6\u4e00\u79cd\u5f62\u5f0f\u7684\u8f93\u51fa\u6570\u636e\u3002<\/p>\n
        Function \u63a5\u53e3\u5b9e\u4f8b<\/h3>\n
        \/**\n * Function\u6d4b\u8bd5\uff0cfunction\u7684\u4f5c\u7528\u662f\u8f6c\u6362\uff0c\u5c06\u4e00\u4e2a\u503c\u8f6c\u4e3a\u53e6\u5916\u4e00\u4e2a\u503c\n *\/\n@Test\npublic void testFunction() {\n    \/\/\u2460 \u4f7f\u7528map\u65b9\u6cd5\uff0c\u6cdb\u578b\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f\u8f6c\u6362\u524d\u7684\u7c7b\u578b\uff0c\u7b2c\u4e8c\u4e2a\u662f\u8f6c\u5316\u540e\u7684\u7c7b\u578b\n    Function function = new Function() {\n        @Override\n        public Integer apply(String s) {\n            return s.length();\/\/\u83b7\u53d6\u6bcf\u4e2a\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\uff0c\u5e76\u4e14\u8fd4\u56de\n        }\n    };\n\n    Stream stream = Stream.of(\"aaa\", \"bbbbb\", \"ccccccc\");\n    Stream stream1 = stream.map(function);\n    stream1.forEach(System.out::println);\n}<\/code><\/pre>\n
        \u8f93\u51fa\u7ed3\u679c<\/p>\n
        3\n5\n7<\/code><\/pre>\n
        \u4ee3\u7801\u5206\u6790<\/h3>\n
        \u2460 `Function`\u63a5\u53e3\u5206\u6790<\/p>\n
        \/\/\u2460 \u4f7f\u7528map\u65b9\u6cd5\uff0c\u6cdb\u578b\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f\u8f6c\u6362\u524d\u7684\u7c7b\u578b\uff0c\u7b2c\u4e8c\u4e2a\u662f\u8f6c\u5316\u540e\u7684\u7c7b\u578b\nFunction function = new Function() {\n    @Override\n    public Integer apply(String s) {\n        return s.length(); \/\/\u83b7\u53d6\u6bcf\u4e2a\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\uff0c\u5e76\u4e14\u8fd4\u56de\n    }\n};<\/code><\/pre>\n
        \u8fd9\u6bb5\u4ee3\u7801\u521b\u5efa\u4e86\u4e00\u4e2a`Function`\u63a5\u53e3\u5bf9\u8c61\uff0c\u5b9e\u73b0\u4e86\u4e00\u4e2a`apply`\u65b9\u6cd5\uff0c\u8fd9\u4e2a\u65b9\u6cd5\u6709\u4e00\u4e2a\u8f93\u5165\u53c2\u6570\u548c\u4e00\u4e2a\u8f93\u51fa\u53c2\u6570\u3002\u5176\u4e2d\uff0c\u6cdb\u578b\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u662f\u8f6c\u6362\u524d\u7684\u7c7b\u578b\uff0c\u7b2c\u4e8c\u4e2a\u662f\u8f6c\u5316\u540e\u7684\u7c7b\u578b\u3002<\/p>\n
        \u5728\u4e0a\u9762\u7684\u4ee3\u7801\u4e2d\uff0c\u5c31\u662f\u83b7\u53d6\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\uff0c\u7136\u540e\u5c06\u6bcf\u4e2a\u5b57\u7b26\u4e32\u7684\u957f\u5ea6\u4f5c\u4e3a\u8fd4\u56de\u503c\u8fd4\u56de\u3002<\/p>\n
        \u2461 \u91cd\u8981\u5e94\u7528 map \u65b9\u6cd5<\/p>\n
        Stream stream = Stream.of(\"aaa\", \"bbbbb\", \"ccccccc\");\nStream stream1 = stream.map(function);\nstream1.forEach(System.out::println);<\/code><\/pre>\n
        \u5728Function<\/code>\u63a5\u53e3\u7684\u91cd\u8981\u5e94\u7528\u4e0d\u5f97\u4e0d\u8bf4Stream<\/code>\u7c7b\u7684map<\/code>\u65b9\u6cd5\uff0cmap<\/code>\u65b9\u6cd5\u4f20\u5165\u4e00\u4e2aFunction<\/code>\u63a5\u53e3\uff0c\u8fd4\u56de\u4e00\u4e2a\u8f6c\u6362\u540e\u7684Stream<\/code>\u7c7b\u3002<\/p>\n
        \u5176\u4ed6 Function \u63a5\u53e3<\/h3>\n
        \u9664\u4e86\u4e0a\u9762\u4f7f\u7528\u7684Function<\/code>\u63a5\u53e3\uff0c\u8fd8\u53ef\u4ee5\u4f7f\u7528\u4e0b\u9762\u8fd9\u4e9bFunction<\/code>\u63a5\u53e3\u3002
        \nIntFunction<\/code>\u3001DoubleFunction<\/code>\u3001LongFunction<\/code>\u3001ToIntFunction<\/code>\u3001ToDoubleFunction<\/code>\u3001DoubleToIntFunction<\/code>\u7b49\u7b49\uff0c\u4f7f\u7528\u65b9\u6cd5\u548c\u4e0a\u9762\u4e00\u6837\u3002<\/p>\n
        Function \u63a5\u53e3\u603b\u7ed3<\/h3>\n
          \n
        • Function<\/code>\u63a5\u53e3\u662f\u4e00\u4e2a\u529f\u80fd\u578b\u63a5\u53e3\uff0c\u662f\u4e00\u4e2a\u8f6c\u6362\u6570\u636e\u7684\u4f5c\u7528<\/li>\n
        • Function<\/code>\u63a5\u53e3\u5b9e\u73b0apply<\/code>\u65b9\u6cd5\u6765\u505a\u8f6c\u6362<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
          \u8fd9\u51e0\u4e2a\u63a5\u53e3\u90fd\u5728java.util.function\u5305\u4e0b\u7684\uff0c\u5206\u522b\u662fConsumer\uff08\u6d88\u8d39\u578b\uff09\u3001supplier\uff08 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[43],"tags":[],"class_list":["post-1752","post","type-post","status-publish","format-standard","hentry","category-java-basic"],"_links":{"self":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/1752","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/comments?post=1752"}],"version-history":[{"count":0,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/1752\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/media?parent=1752"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/categories?post=1752"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/tags?post=1752"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}