Future 异步回调

异步调用

/*异步调用
* ajax: 客户端服务器
* future: java类CompletableFuture<T>
* 1. 异步执行
* 2. 成功回调
* 3. 失败回调*/
public class Demo01 {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
       /* //发起一个请求  没有返回值的异步回调
        CompletableFuture<Void> completableFuture = CompletableFuture.runAsync(()->{
            try {
                TimeUnit.SECONDS.sleep(2);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName()+" runAsync=>Void");
        });
        System.out.println("1111"); //立刻输出
        Void aVoid = completableFuture.get();//获取执阻塞行结果  异步输出*/

        //发起一个请求  有返回值的异步回调
        /*
        * 失败时返回错误信息*/
        CompletableFuture<Integer> completableFuture = CompletableFuture.supplyAsync(() -> {
          //  int i=10/0;  //故意制造错误信息
            System.out.println(Thread.currentThread().getName()+" runAsync=>Void");
            return 1024;
        });
        System.out.println(completableFuture.whenComplete((t, u) -> {
            System.out.println("t->" + t);  //正常的返回结果
            System.out.println("u->" + u);
        }).exceptionally((e) -> {
            e.getMessage();
            return 2333;
        }).get());
    }
}
//错误结果
/*
t->null
u->java.util.concurrent.CompletionException: java.lang.ArithmeticException: / by zero
2333
*/
//成功结果
/*
ForkJoinPool.commonPool-worker-9 runAsync=>Void
t->1024
u->null
1024
*/