异步回调

Future 设计的初衷：对将来的某个事件的结果进行建模 

package com.kuang.future;

import com.kuang.pc.C;

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;

/**
 * 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 {
//        //发起一个请求  无返回值 void
//        CompletableFuture completableFuture=CompletableFuture.runAsync(()->{
//            try {
//                TimeUnit.SECONDS.sleep(2);
//            } catch (InterruptedException e) {
//                e.printStackTrace();
//            }
//            System.out.println(Thread.currentThread().getName()+"->runAsync()->void");
//        });
//        System.out.println("11111");
//        completableFuture.get();//获取阻塞执行结果

        //有返回值的  supplyAsync 异步回调
        //ajax，成功与失败的回调
        // 返回的是错误信息
        CompletableFuture completableFuture= CompletableFuture.supplyAsync(()->{
            System.out.println(Thread.currentThread().getName()+"->supplyAsync()->Integer");
           int i=1/0;
            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);//有错误打印错误信息:u=>java.util.concurrent.CompletionException: java.lang.ArithmeticException: / by zero
        }).exceptionally(e -> {
            System.out.println(e.getMessage());
            return 233;//可以获取到错误的返回结果
        }).get());


        /**
         * success code 200
         * error code 404 500
         */
    }

}