异步调用

CompletableFuture

异步执行

成功回调

失败回调

public class Demo01 {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        //没有返回值的runAsync 异步回调
        CompletableFuture<Void> completableFuture = CompletableFuture.runAsync(()->{
            try {
                TimeUnit.SECONDS.sleep(2);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName());
        });

        System.out.println("111");

        completableFuture.get();//阻塞获取执行结果

        //有返回值的异步回调
        //ajax 成功和失败的回调
        //返回的是错误的信息
        CompletableFuture<Integer> cf = CompletableFuture.supplyAsync(()->{
            System.out.println(Thread.currentThread().getName());
            int i = 10/0;
            return 1024;
        });

        System.out.println(cf.whenComplete((t, u) -> {
            System.out.println("t=>" + t);//正确的返回结果
            System.out.println("u=>" + u);//错误信息java.util.concurrent.CompletionException: java.lang.ArithmeticException: / by zero
        }).exceptionally((e) -> {
            System.out.println(e.getMessage());
            return 233;//可以获取错误的返回结果
        }).get());
    }
}