JAVA8-CompletableFuture基本用法 JAVA8-CompletableFuture基本用法针对<实现一个异步基于事件回调的Future程序> 用CompletableFuture进行改进。代码示例：package com.example.study.java8.completableFutures; import java.util.Optional; import java.util.Random; import java.util.concurrent.CompletableFuture; import java.util.concurrent.ExecutionException; /** * CompletableFuture 基本用法 */ public class CompletableFutureInAction1 { private final static Random RANDOM = new Random(System.currentTimeMillis()); public static void main(String[] args) throws ExecutionException, InterruptedException { //实际开发中，一般不直接new，而是使用工厂创建 // CompletableFuture<Void> voidCompletableFuture = CompletableFuture.runAsync(); CompletableFuture<Double> completableFuture = new CompletableFuture<>(); new Thread(()->{ double value = get(); completableFuture.complete(value); }).start(); //不会阻塞程序执行 System.out.println("===========no====block====.."); //1、后面获取程序执行结果 // Optional.ofNullable(completableFuture.get()).ifPresent(System.out::println); //2、执行完后，通过回调自动返回结果 completableFuture.whenComplete((v,t)->{ Optional.ofNullable(v).ifPresent(System.out::println); Optional.ofNullable(t).ifPresent(x->x.printStackTrace()); }); } private static double get(){ try { Thread.sleep(RANDOM.nextInt(10000)); } catch (InterruptedException e) { e.printStackTrace(); } return RANDOM.nextDouble(); } }输出结果：===========no====block====.. 0.5192854493861505