{"id":10006978,"date":"2022-12-15T19:48:11","date_gmt":"2022-12-15T11:48:11","guid":{"rendered":"https:\/\/ityet.com\/?p=10006978"},"modified":"2022-12-15T19:48:11","modified_gmt":"2022-12-15T11:48:11","slug":"%e4%b8%8ecompletablefuture%e6%9c%89%e5%85%b3%e7%9a%84%e4%b8%80%e4%ba%9b%e7%9f%a5%e8%af%86","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10006978","title":{"rendered":"\u4e0eCompletableFuture\u6709\u5173\u7684\u4e00\u4e9b\u77e5\u8bc6"},"content":{"rendered":"

Java1.5\u5f15\u5165\u4e86Future\uff0c\u57281.8\u4e2d\u53c8\u5f15\u5165\u4e86CompletableFuture\u3002\u4ed6\u7684\u51fa\u73b0\u53ef\u4ee5\u4f7f\u6211\u4eec\u66f4\u597d\u7684\u53bb\u5bf9\u4efb\u52a1\u8fdb\u884c\u7f16\u6392\uff0c\u5408\u7406\u7684\u4f7f\u7528\u4f1a\u6781\u5927\u7684\u7f29\u51cf\u591a\u4efb\u52a1\u7684\u5904\u7406\u65f6\u95f4\uff0c\u8fbe\u5230\u4e8b\u534a\u529f\u500d\u7684\u76ee\u7684\u3002\u4e0b\u9762\u8ba9\u6211\u4eec\u4e00\u5757\u6765\u770b\u4e00\u4e0b\u4e0e\u5b83\u76f8\u5173\u7684\u4e00\u4e9b\u77e5\u8bc6\u3002<\/p><\/blockquote>\n

1 Java\u4e2d\u7684\u51fd\u6570\u5f0f\u7f16\u7a0b<\/h3>\n

\u5728\u770bCompletableFuture\u4e86\u89e3\u4e00\u70b9Java\u4e2d\u51fd\u6570\u5f0f\u7f16\u7a0b\u76f8\u5173\u7684\u77e5\u8bc6\u4f1a\u66f4\u6709\u7528\u4e00\u4e9b\u3002<\/p>\n

\u5728Java1.8\u4e2d\u5f15\u5165\u4e86@FunctionalInterface<\/code>\uff0c\u540c\u65f6\u4e5f\u5728java.util.function<\/code>\u5305\u4e2d\u5f15\u5165\u4e86\u5f88\u591a\u51fd\u6570\u5f0f\u63a5\u53e3\u3002\u6211\u4eec\u6765\u770b\u51e0\u4e2a\u5e38\u89c1\u7684:<\/p>\n

1.1 Consumer<\/h4>\n

Consumer\u6d88\u8d39\u8005\uff0c\u5173\u8054\u7684\u65b9\u6cd5\u4e3avoid accept(T t)<\/code>\uff0c\u6709\u53c2\u65e0\u8fd4\u56de\u503c\u3002<\/p>\n

@FunctionalInterface\npublic interface Consumer<T> {\n\n    void accept(T t);<\/code><\/pre>\n
1.2 Function<\/h4>\n
Function\u51fd\u6570\uff0c\u5173\u8054\u65b9\u6cd5\u4e3aR apply(T t)<\/code>\uff0c\u6709\u53c2\u6709\u8fd4\u56de\u503c\u3002<\/p>\n
@FunctionalInterface\npublic interface Function<T, R> {\n\n    R apply(T t);<\/code><\/pre>\n
1.3 Predicate<\/h4>\n
Predicate\u8c13\u8bed(\u65ad\u8a00?)\uff0c\u5173\u8054\u65b9\u6cd5\u4e3aboolean test(T t)<\/code>\uff0c\u6709\u53c2\u6709\u8fd4\u56de\u503c(bool)\u3002<\/p>\n
@FunctionalInterface\npublic interface Predicate<T> {\n\n    boolean test(T t);<\/code><\/pre>\n
1.4 Supplier<\/h4>\n
Supplier\u4f9b\u5e94\u8005\uff0c\u5173\u8054\u65b9\u6cd5\u4e3aT get()<\/code>\uff0c\u65e0\u53c2\u6709\u8fd4\u56de\u503c\u3002<\/p>\n
@FunctionalInterface\npublic interface Supplier<T> {\n\n    T get();\n}<\/code><\/pre>\n
2 CompletableFuture<\/h3>\n
\u540e\u7eed\u7684\u5185\u5bb9\u4e3b\u8981\u5173\u6ce8\u70b9\u4f1a\u653e\u5728\u5176\u5185\u90e8\u5404\u79cdAPI\u4e0a\u9762\u3002\u5728\u540e\u7eed\u7684\u65b9\u6cd5\u4e2d\uff0c\u56e0\u4e3aCompletableFuture<\/code>\u5b9e\u73b0\u4e86CompletionStage<\/code>\u4f7f\u5176\u5177\u6709\u94fe\u5f0f\u8c03\u7528\u80fd\u529b\u3002\u5927\u591a\u6570\u65b9\u6cd5\u90fd\u4f1a\u7c7b\u4f3c\u5982\u4e0b:<\/p>\n
    \n
  • xxx(Function func): \u4f1a\u4e0a\u6587\u7684\u540c\u4e00\u7ebf\u7a0b<\/code>\u53bb\u6267\u884c\u5f53\u524d\u4efb\u52a1<\/li>\n
  • xxxAsync(Function func): \u4f1a\u542f\u7528\u4e00\u4e2a\u65b0\u7ebf\u7a0b<\/code>\u53bb\u6267\u884c\u5f53\u524d\u4efb\u52a1<\/li>\n
  • xxxAsync(Function func, Executor executor): \u4f1a\u4f7f\u7528executor<\/code>\u7ebf\u7a0b\u6c60\u4e2d\u7684\u65b0\u7ebf\u7a0b<\/code>\u53bb\u6267\u884c\u5f53\u524d\u4efb\u52a1<\/li>\n<\/ul>\n
    2.1 CompletableFuture\u7684\u521b\u5efa<\/h4>\n
      \n
    • supplyAsync<\/code>: \u4ee5Supplier<\/code>\u4e3a\u53c2\uff0c\u6709\u8fd4\u56de\u503c\u3002<\/li>\n<\/ul>\n
      public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier)\npublic static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier, Executor executor)<\/code><\/pre>\n
        \n
      • runAsync<\/code>: \u4ee5Runnable<\/code>\u4e3a\u53c2\uff0c\u8fd4\u56de\u503c\u4e3aVoid<\/code>\u3002<\/li>\n<\/ul>\n
        public static CompletableFuture<Void> runAsync(Runnable runnable)\npublic static CompletableFuture<Void> runAsync(Runnable runnable, Executor executor)<\/code><\/pre>\n
          \n
        • completedFuture<\/code>: \u521b\u5efa\u4e00\u4e2a\u5df2\u6709\u503c\u4e14\u5b8c\u6210\u7684CompletableFuture\u3002<\/li>\n<\/ul>\n
          public static <U> CompletableFuture<U> completedFuture(U value)<\/code><\/pre>\n
            \n
          • failedFuture<\/code>: \u521b\u5efa\u4e00\u4e2a\u5df2\u51fa\u73b0\u5f02\u5e38\u4e14\u5b8c\u6210\u7684CompletableFuture\u3002<\/li>\n<\/ul>\n
            public static <U> CompletableFuture<U> failedFuture(Throwable ex)<\/code><\/pre>\n
            \u53ef\u4ee5\u770b\u5230runAsync<\/code>\u548csupplyAsync<\/code>\u90fd\u63d0\u4f9b\u4e86\u989d\u5916\u53c2\u6570Executor<\/code>\uff0c\u5728\u672a\u6307\u5b9aexecutor<\/code>\u65f6\uff0c\u9ed8\u8ba4\u4f1a\u4f7f\u7528ForkJoinPool.commonPool()<\/code>\u6765\u6267\u884c\u5f02\u6b65\u4efb\u52a1\uff0c\u800cParallel Stream<\/code>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u4e5f\u4f1a\u4f7f\u7528\u8be5\u7ebf\u7a0b\u6c60\uff0c\u5171\u7528\u7684\u8bdd\u53ef\u80fd\u4f1a\u5bfc\u81f4\u975e\u6838\u5fc3\u4e1a\u52a1\u62a2\u5360\u6838\u5fc3\u4e1a\u52a1\u7684\u6267\u884c\u3002\u4e00\u822c\u6765\u8bf4\u90fd\u4f1a\u4f7f\u7528\u81ea\u5b9a\u4e49\u7ebf\u7a0b\u6c60\u6765\u6267\u884c\u8fd9\u4e9b\u4efb\u52a1\u3002<\/p>\n
            2.2 CompletableFuture\u7684\u540e\u7eed\u64cd\u4f5c<\/h4>\n
            2.2.1 \u6267\u884c\u4e00\u4e2a\u4efb\u52a1(1)<\/h5>\n
              \n
            • apply<\/code>: \u6709\u53c2\u6709\u8fd4\u56de\u503c\u3002\u4f1a\u5c06\u524d\u9762\u7684\u8fd4\u56de\u503c\u4f5c\u4e3a\u5f53\u524d\u51fd\u6570\u7684\u8f93\u5165\u3002<\/li>\n<\/ul>\n
              public <U> CompletableFuture<U> thenApply(Function<? super T,? extends U> fn)\npublic <U> CompletableFuture<U> thenApplyAsync(Function<? super T,? extends U> fn)\npublic <U> CompletableFuture<U> thenApplyAsync(Function<? super T,? extends U> fn, Executor executor)<\/code><\/pre>\n
                \n
              • accept<\/code>: \u6709\u53c2\u65e0\u8fd4\u56de\u503c\u3002\u4f1a\u5c06\u524d\u9762\u7684\u8f93\u51fa\u4f5c\u4e3a\u5f53\u524d\u51fd\u6570\u7684\u8f93\u5165\u3002<\/li>\n<\/ul>\n
                public CompletableFuture<Void> thenAccept(Consumer<? super T> action)\npublic CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action)\npublic CompletableFuture<Void> thenAcceptAsync(Consumer<? super T> action, Executor executor)<\/code><\/pre>\n
                  \n
                • run<\/code>: \u7f16\u6392\u6267\u884c\u53e6\u5916\u4e00\u4e2a\u6beb\u65e0\u76f8\u5173\u7684\u4efb\u52a1<\/li>\n<\/ul>\n
                  public CompletableFuture<Void> thenRun(Runnable action)\npublic CompletableFuture<Void> thenRunAsync(Runnable action)\npublic CompletableFuture<Void> thenRunAsync(Runnable action, Executor executor)<\/code><\/pre>\n
                  \u793a\u4f8b<\/p>\n
                  @Test\nvoid testApply() throws ExecutionException, InterruptedException {\n    final CompletableFuture<Integer> future = CompletableFuture\n            .supplyAsync(() -> 1)\n            .thenApply((val) -> val + 1);\n    assertEquals(2, future.get());\n}\n\n@Test\nvoid testAccept() {\n    final CompletableFuture<Void> future = CompletableFuture\n            .supplyAsync(() -> 1)\n            .thenAccept((val) -> {\n                assertEquals(1, val);\n            });\n    future.join();\n}\n\n@Test\nvoid testRun() {\n    final CompletableFuture<Void> future = CompletableFuture\n            .supplyAsync(() -> 1)\n            .thenRun(() -> {});\n    future.join();\n}<\/code><\/pre>\n
                  2.2.1 \u6267\u884c\u4e00\u4e2a\u4efb\u52a1(2)<\/h5>\n
                    \n
                  • whenComplete<\/code>: \u5f53\u4efb\u52a1\u5b8c\u6210\u65f6\u6267\u884c\u8be5\u65b9\u6cd5\uff0c\u5c06\u8fd4\u56de\u503c\u53ca\u5f02\u5e38\u4f20\u5165BiConsumer<\/code>(\u6709\u53c2\u65e0\u8fd4\u56de\u503c)<\/li>\n<\/ul>\n
                    public CompletableFuture<T> whenComplete(BiConsumer<? super T, ? super Throwable> action)\npublic CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T, ? super Throwable> action)\npublic CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T, ? super Throwable> action, Executor executor)<\/code><\/pre>\n
                      \n
                    • exceptionally<\/code>: \u5f53\u76f8\u5e94\u7684\u4efb\u52a1\u51fa\u73b0\u5f02\u5e38\u65f6\u4f1a\u8c03\u7528\u8be5\u65b9\u6cd5\uff0c\u5c06\u5f02\u5e38\u4f5c\u4e3a\u53c2\u6570\u4f20\u8fdb\u6765<\/li>\n<\/ul>\n
                      public CompletableFuture<T> exceptionally(Function<Throwable, ? extends T> fn)\npublic CompletableFuture<T> exceptionallyAsync(Function<Throwable, ? extends T> fn)\npublic CompletableFuture<T> exceptionallyAsync(Function<Throwable, ? extends T> fn, Executor executor)<\/code><\/pre>\n