创建多线程方式1：继承Thread开启多线程下载图片（不推荐，java的单一继承性）

package com.Java;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;
import java.net.URL;

//练习多线程Thread，实现多线程下载图片
public class TestThread2 extends Thread{
    private String url;//保存图片地址
    private String name;//保存的文件名

    public TestThread2(String url,String name) {
        this.url=url;
        this.name=name;
    }

//    下载图片的执行体
    @Override
    public void run() {
    WebDownloader webDownloader = new WebDownloader();
    webDownloader.downloader(url, name);
        System.out.println("下载了文件"+name);
    }

    public static void main(String[] args) {
        TestThread2 thread1 = new TestThread2("https://www.kuangstudy.com/assert/course/c1/01.jpg","img1.jpg");
        TestThread2 thread2 = new TestThread2("https://www.kuangstudy.com/assert/course/c1/02.jpg","img2.jpg");
        TestThread2 thread3 = new TestThread2("https://www.kuangstudy.com/assert/course/c1/03.jpg","img3.jpg");
//        因为多线程 所以是一起执行 并非t1t2t3
        thread1.start();
        thread2.start();
        thread3.start();
    }
//    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("IO异常，downloader方法出现了问题");
            }
        }
        }
}