12.Future异步回调

Future异步回调

Future设计的初衷，对将来的某个时间的结果进行建模

/*
异步调用 CompletableFuture
异步执行，成功回调，失败回调
*输出结果：
111111111
ForkJoinPool.commonPool-worker-1runAsync void
* */
public class Demo01 {
    public static void main(String[] args) throws Exception {
        //test1();//无返回值的
        test2();//有返回值的
    }

    //无返回值的异步回调
    public static void test1() throws ExecutionException, InterruptedException {
        //发起一个请求，没有返回值的异步回调
        CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {
            try {
                TimeUnit.SECONDS.sleep(2);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName() + "runAsync void");
        });
        System.out.println(111111111);
        //阻塞 获取执行结果
        future.get();
    }

    //有返回值的异步回调,有成功，有失败
    //ajax success fail
    public static void test2() throws ExecutionException, InterruptedException {
        CompletableFuture<Integer> future = CompletableFuture.supplyAsync(() -> {
            System.out.println(Thread.currentThread().getName() + "supplyAsync==》Integer");
            //int i = 2 / 0;
            return 1024;//成功返回1024
        });

        System.out.println(future.whenComplete((t, u) -> {
            System.out.println("t==" + t);//正常的返回结果
            System.out.println("u==" + u);//错误信息
        }).exceptionally((e) -> {//失败
            System.out.println(e.getMessage());
            return 123;//失败返回233
        }).get());
    }
}