异步回调 异步回调对将来某个事件的结果进行建模package com.sw.future; import java.util.concurrent.CompletableFuture; import java.util.concurrent.ExecutionException; import java.util.concurrent.TimeUnit; /** * @Author suaxi * @Date 2021/2/18 23:40 * 异步回调 */ public class Test01 { 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() + " runAsync"); // }); // System.out.println("无返回值的异步回调测试"); // completableFuture.get(); //有返回值的 supplyAsync 异步回调 CompletableFuture<Integer> completableFuture = CompletableFuture.supplyAsync(() -> { System.out.println(Thread.currentThread().getName() + " supplyAsync"); int i = 1/0; return 200; }); System.out.println(completableFuture.whenComplete((t, u) -> { System.out.println("t= " + t); //正常返回的结果 System.out.println("u= " + u); //错误信息：java.util.concurrent.CompletionException: java.lang.ArithmeticException: / by zero }).exceptionally((e) -> { //链式编程 System.out.println(e.getMessage()); return 404; //错误信息的返回结果 }).get()); } }