CompletableFuture

最新推荐文章于 2023-05-05 22:25:50 发布

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本文通过一个具体的Java示例介绍了如何使用CompletableFuture来执行异步任务，并展示了带阻塞与不带阻塞的任务执行方式及其结果处理过程。

public class TestCompletableFuture {

    private static final Executor executor = Executors.newFixedThreadPool(4);

    private static void submitSleep(int id) {
        CompletableFuture<String> resultCF = CompletableFuture.supplyAsync(new Supplier<String>() {
            @Override
            public String get() {
                try {
                    // sleep会释放执行权 但不会释放锁 wait会释放执行权和锁
                    TimeUnit.SECONDS.sleep(2);
                } catch (InterruptedException ie) {
                    ie.printStackTrace();
                }
                return new StringBuffer("success").append(id).toString();
            }
        }, executor);
        // result
        resultCF.thenAccept(new Consumer<String>() {
            @Override
            public void accept(String s) {
                System.out.println(new StringBuffer(s).append("    :").append(System.currentTimeMillis()).toString());
            }
        });
    }

    private static void submit(int id) {
        CompletableFuture<String> resultCF = CompletableFuture.supplyAsync(new Supplier<String>() {
            @Override
            public String get() {
                return new StringBuffer("success").append(id).toString();
            }
        }, executor);
        // result
        resultCF.thenAccept(new Consumer<String>() {
            @Override
            public void accept(String s) {
                System.out.println(new StringBuffer(s).append("    :").append(System.currentTimeMillis()).toString());
            }
        });
    }

    public static void main(String args[]) {
        System.out.println("start submit:" + System.currentTimeMillis());
        for (int i=1; i<6; i++) {
            submitSleep(i);
        }
        for (int i=6; i<11; i++) {
            submit(i);
        }
        System.out.println("  end submit:" + System.currentTimeMillis());
    }
}