Question

我已经编写了一个小程序来测试CompletableFuture行为，但不清楚如何在执行任务时创建和使用线程。

package com.my.testprog.concurrjava;

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class CompFuture {

    ExecutorService firstExecService = Executors.newFixedThreadPool(2);
    ExecutorService secondExecService = Executors.newFixedThreadPool(2);

    public CompFuture() {
    }

    public String returnSalutation(String param) {
        System.out.println("RS: " + Thread.currentThread());
        return param + " Hello my";
    }

    public void returnGreetings(String salutation) {
        System.out.println("RG: " + Thread.currentThread());
        System.out.println("RG: " + salutation + " Friend!");
    }

    public void testMe(String start) {
        System.out.println("TM: " + Thread.currentThread());
        CompletableFuture.supplyAsync(() -> returnSalutation(start), firstExecService)
            .thenAccept(s -> returnGreetings(s));
    }

    public static void main(String[] args) {
        CompFuture compFuture = new CompFuture();
        compFuture.testMe("Java");

        compFuture.firstExecService.shutdown();
        compFuture.secondExecService.shutdown();
    }
}

当我运行程序时，它会显示以下输出：

TM: Thread[main,5,main]
RS: Thread[pool-1-thread-1,5,main]
RG: Thread[main,5,main]
RG: Java Hello my Friend!

我的理解是，它将使用相同的线程来调用“ supplyAsync”和“ thenAccept”方法。但是，以上结果表明仅在单独的线程中执行了“ supplyAsync”，而在主线程中运行了“ thenAccept”。

有人可以详细说明吗？

“ supplyAsync”和“ thenAccept”的CompletableFuture线程ID

0 个答案: