创建多线程方式3：实现Callable接口 改造下载图片案例

package com.Test;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.concurrent.*;

//开启线程方式三：实现Callable接口
//实现Callable的好处
//可以抛出异常
//可以获取返回值

public class TestCallable implements Callable<Boolean> {

    private String url;
    private String name;
    public TestCallable(String url,String name){
        this.url=url;
        this.name=name;
    }

    @Override
    public Boolean call() {
       WebDownLoader webDownLoader = new WebDownLoader();
        webDownLoader.downloader(url,name);
        System.out.println("下载了"+name);
        return true;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        TestCallable thread1 = new TestCallable("https://www.kuangstudy.com/assert/course/c1/04.jpg","4.jpg");
        TestCallable thread2 = new TestCallable("https://www.kuangstudy.com/assert/course/c1/05.jpg","5.jpg");
        TestCallable thread3 = new TestCallable("https://www.kuangstudy.com/assert/course/c1/06.jpg","6.jpg");

//        创建执行服务
        ExecutorService ser = Executors.newFixedThreadPool(3);
//        提交执行
        Future<Boolean> r1 = ser.submit(thread1);
        Future<Boolean> r2 = ser.submit(thread2);
        Future<Boolean> r3 = ser.submit(thread3);
//        获取结果
        boolean rs1 = r1.get();
        boolean rs2 = r2.get();
        boolean rs3 = r3.get();
//        关闭服务
        ser.shutdownNow();
    }

    //    下载器
    class WebDownLoader{
        //下载方法
        public void downloader(String url,String name){
            try {
                FileUtils.copyURLToFile(new URL(url), new File(name));
            } catch (IOException e) {
                e.printStackTrace();
                System.out.println("下载器有问题，downloader方法有bug");
            }
        }
    }
}