多线程——继承Thread类

继承Thread类，重写run()方法，调用start并开启线程

package com.sympa.lesson01;

//创建线程方式一：继承Thread类，重写run()方法，调用start并开启线程
public class TestThread1 extends Thread{
    @Override
    public void run(){
        //run方法线程体
        for (int i = 0; i < 200; i++) {
            System.out.println("我在看片\n" + i);
        }
    }
    public static void main(String[] args){
        //main线程，主线程

        //创建一个线程对象
        TestThread1 testThread1 = new TestThread1();

        //调用start()方法开启线程
        testThread1.start();
        //线程开启不一定立即执行，由CPU调度执行
        for (int i = 0; i < 200; i++) {
            System.out.println("我在学习\n" + i);
        }
    }
}

练习Thread，实现多线程下载图片

package com.sympa.lesson01;

import org.apache.commons.io.FileUtils;

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

//练习Thread，实现多线程下载图片
public class TestThread02 extends Thread{
    private String url;
    private String name;
    public TestThread02(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("下载了文件名为：" + name);
    }

    public static void main(String[] args){
        TestThread02 t1 = new TestThread02("https://sympawang.com/images/7%E7%A7%8Djoin.png", "01.jpg");
        TestThread02 t2 = new TestThread02("https://sympawang.com/images/7%E7%A7%8Djoin.png", "02.jpg");
        TestThread02 t3 = new TestThread02("https://sympawang.com/images/7%E7%A7%8Djoin.png", "03.jpg");
        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\n");
        }
    }
}