Java简单实现多线程——继承thread类

package com.cl.demo01;


//创建线程方式一；继承Thread类，重写run（）方法，调用start开启线程
public class TestThread1 extends Thread{
    @Override
    public void run() {
        //run方法线程体
        for (int i = 0; i <100; i++) {
            System.out.println("run方法--"+i);
        }
    }

    public static void main(String[] args) {
        //main线程，主线程

        TestThread1 thread1 = new TestThread1();

        thread1.start();

        for (int i = 0; i <100; i++) {
            System.out.println("多线程--"+i);
        }
    }
}

/*
总结：注意，线程开启不一定立即执行，由cpu调度执行
* */

注意,在实现前，需去官网下载“commons io.jar”这个jar包，因为要利用里面的工具去实现；

package com.cl.demo01;

import org.apache.commons.io.FileUtils;

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

public class TestThread2 extends Thread {

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

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

    @Override
    public void run() {
        WebDownloader webDownloader = new WebDownloader();
        webDownloader.downloader(url,name);
        System.out.println("下载文件名："+name);
    }

    public static void main(String[] args) {
        TestThread2 t1 = new TestThread2("https://pic.cnblogs.com/avatar/2053539/20200904094641.png","th1");
        TestThread2 t2 = new TestThread2("https://pic.cnblogs.com/face/1959021/20200303171942.png","th2");
        TestThread2 t3 = new TestThread2("https://pic.cnblogs.com/face/2124548/20200820122225.png","th3");

        t1.start();
        t2.start();
        t3.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方法出现问题");

        }
    }
}