java多线程 Callable 接口 实现图片下载

编写代码

package com.xiang.lesson06;

import org.apache.commons.io.FileUtils;

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

// 实现Callable  接口；
public class TestCallable implements Callable {

    private String url; //网络图片地址
    private String name;//保存的文件名

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

    }
    @Override
    public Boolean call() throws Exception {
        WebDownloader downloader = new WebDownloader();
        downloader.downloader(url,name);
        System.out.println("下载了文件名："+name);
        return true;
    }


    public static void main(String[] args) throws Exception {
        TestCallable t1 = new TestCallable("https://img-home.csdnimg.cn/images/20210907093842.jpg","t1.jpg");
        TestCallable t2 = new TestCallable("https://img-blog.csdnimg.cn/234ef937b8924d0a81271085511f6223.png","t2.jpg");
        TestCallable t3 = new TestCallable("https://img-blog.csdnimg.cn/img_convert/baf51d796db22a6a03c0ce7caf378f6f.png","t3.jpg");

//创建执行服务
        ExecutorService pool = Executors.newFixedThreadPool(3);
//        提交执行
        Future s1 = pool.submit(t1);
        Future s2 = pool.submit(t2);
        Future s3 = pool.submit(t3);
//        获取结果
        Object o1 = s1.get();
        Object o2 = s2.get();
        Object o3 = s3.get();
//        关闭服务
        pool.shutdownNow();

    }
}


class WebDownloader {
    //    下载方法
    public void downloader(String url, String name) {
        try {
//             copyURLToFile 把网页地址，变成一个文件；
            FileUtils.copyURLToFile(new URL(url), new File(name));
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("IO异常，downloader方法出现问题");
        }
    }
}

运行结果