Java CompletableFuture组合拼装异步线程任务（2）

小鱼儿 2023-10-17 21:49 7阅读 0赞

**Java CompletableFuture组合拼装异步线程任务**

private void seq() throws ExecutionException, InterruptedException {
            System.out.println("时间1:" + System.currentTimeMillis());
            CompletableFuture<String> f1 = CompletableFuture.supplyAsync(new Supplier<String>() {
                @Override
                public String get() {
                    try {
                        TimeUnit.SECONDS.sleep(3);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
    
                    return "2018";
                }
            });
    
            System.out.println("时间2:" + System.currentTimeMillis());
            CompletableFuture<Integer> f2 = f1.thenApply(new Function<String, Integer>() {
                @Override
                public Integer apply(String s) {
                    try {
                        TimeUnit.SECONDS.sleep(3);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
    
                    return Integer.parseInt(s);
                }
            });
    
            System.out.println("时间3:" + System.currentTimeMillis());
            CompletableFuture<Double> f3 = f2.thenApply(new Function<Integer, Double>() {
                @Override
                public Double apply(Integer i) {
                    try {
                        TimeUnit.SECONDS.sleep(3);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
    
                    return (double) i;
                }
            });
    
            System.out.println("时间4:" + System.currentTimeMillis());
            f3.whenComplete((v, a) -> {
                System.out.println("v: " + v);
                System.out.println("a: " + a);
            });
            System.out.println("时间5:" + System.currentTimeMillis());
            System.out.println(f3.get());
            System.out.println("时间6:" + System.currentTimeMillis());
        }

输出结果：

06-12 18:49:08.337 6047-6047/zhangphil.test I/System.out: 时间1:1528800548337
    06-12 18:49:08.339 6047-6047/zhangphil.test I/System.out: 时间2:1528800548339
    06-12 18:49:08.340 6047-6047/zhangphil.test I/System.out: 时间3:1528800548340
    06-12 18:49:08.341 6047-6047/zhangphil.test I/System.out: 时间4:1528800548341
    06-12 18:49:08.342 6047-6047/zhangphil.test I/System.out: 时间5:1528800548342
    06-12 18:49:17.347 6047-6089/zhangphil.test I/System.out: v: 2018.0
        a: null
    06-12 18:49:17.347 6047-6047/zhangphil.test I/System.out: 2018.0
    06-12 18:49:17.348 6047-6047/zhangphil.test I/System.out: 时间6:1528800557348