实现Callable接口

package edu.wtbu;

import org.apache.commons.io.FileUtils;

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

/*
callable的好处
  1.可以定义返回值
  2.可以抛出异常
 */
public class Demo01 implements Callable {
    private  String url;//网络图片地址
    private  String name;//保存的文件名

    public Demo01(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("下载了文件名为："+name);
        return true;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        Demo01 demo01 = new Demo01("https://b0.bdstatic.com/ugc/yQ2BNBkVVb_E0IpmtFRrbwb7809eeba6400217fa19fdb7ec0ca44d.jpg@h_1280","1.jpg");
        Demo01 demo02 = new Demo01("https://img2.baidu.com/it/u=3393071480,1773077460&fm=253&fmt=auto&app=120&f=JPEG?w=1421&h=800","2.jpg");
        Demo01 demo03 = new Demo01("https://pic.rmb.bdstatic.com/bjh/02f9ad62ee8b9fd91d97fccc033b4868.jpeg@wm_2,t_55m+5a625Y+3L0FZU1UzMjQ=,fc_ffffff,ff_U2ltSGVp,sz_18,x_12,y_12","3.jpg");

        //创建执行服务
        ExecutorService ser = Executors.newFixedThreadPool(3);

        //提交执行
        Future<Boolean> r1 = ser.submit(demo01);
        Future<Boolean> r2 = ser.submit(demo02);
        Future<Boolean> r3 = ser.submit(demo03);

        //获取结果
        boolean rs1=r1.get();
        boolean rs2=r2.get();
        boolean rs3=r3.get();

        System.out.println(rs1);
        System.out.println(rs2);
        System.out.println(rs3);

        //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) {
            System.out.println("IO异常");
        }

    }
}