java-多线程future等待返回

多线程中需要返回值, java中有个fork/join模型, 没有细研究, 简单实用callable进行了返回

Thread1

package com.iwhere.easy.travel.test.thread;

import java.util.concurrent.Callable;

import org.springframework.web.client.RestTemplate;

import com.alibaba.fastjson.JSONObject;

public class Thread1 implements Callable<String>{

    @Override
    public String call() throws Exception {
        Thread.sleep(5000);
        System.out.println("thread1 sleep 5s");
        new RestTemplate().getForObject("http://abc.2314", JSONObject.class);
        return "i am thread one";
    }

}

Thread2

package com.iwhere.easy.travel.test.thread;

import java.util.concurrent.Callable;

public class Thread2 implements Callable<String>{

    @Override
    public String call() throws Exception {
        Thread.sleep(2000);
        System.out.println("thread2 sleep 2s");
        
        if (1 == 1) throw new RuntimeException();
        
        return "i am thread two";
    }

}

Thread3

package com.iwhere.easy.travel.test.thread;

import java.util.concurrent.Callable;

public class Thread3 implements Callable<String>{

    @Override
    public String call() throws Exception {
        Thread.sleep(8000);
        System.out.println("thread3 sleep 8s");
//        Thread.currentThread().interrupt();
        return "i am thread three";
    }

}

main类

package com.iwhere.easy.travel.test.thread;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class MyThreadTest {

    private static ExecutorService threadPool = Executors.newFixedThreadPool(20);

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        
        Thread1 thread1 = new Thread1();
        Future<String> futureTask1 = threadPool.submit(thread1);
        
        Thread2 thread2 = new Thread2();
        Future<String> futureTask2 = threadPool.submit(thread2);
        
        Thread3 thread3 = new Thread3();
        Future<String> futureTask3 = threadPool.submit(thread3);
        
        String string1 = null;
        String string2 = null;
        String string3 = null;
        
        try {
            string1 = futureTask1.get();
        }catch (Exception e) {
            futureTask1.cancel(true);
        }
        try {
            string2 = futureTask2.get();
        }catch (Exception e) {
            futureTask2.cancel(true);
        }
        try {
            string3 = futureTask3.get();
        }catch (Exception e) {
            futureTask3.cancel(true);
        }
        
//        Thread.currentThread().wait(1000);
//        futureTask1.cancel(true);
//        futureTask2.cancel(true);
//        futureTask3.cancel(true);
        
        System.out.println(string1 + ": " + string2 + ": " + string3);
        
        threadPool.shutdown();
    }
}

这样在线程中抛出异常,仍然可以,

有一个问题仍然存在, 要是线程中莫名停止了, 就不会反回值 了..