java多线程

10 多线程

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创建多线程之方式一

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package 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 < 20; i++) {
            System.out.println("我在看代码---"+i);
        }
    }
    public static void main(String[] args) {
        //main线程，主线程
        //创建线程对象，开启线程
        //线程开启不一定立即执行，由cpu调度
        new TestThread1().start();
        for (int i = 0; i < 200; i++) {
            System.out.println("我在学习多线程**"+i);
        }
    }
}

多线程下载图片

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package demo01;

import org.apache.commons.io.FileUtils;

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

//练习Thread，实现多线程同步下载图片
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("下载文件名为"+name);
    }

    public static void main(String[] args) {
        TestThread2 t1=new TestThread2("https://dss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=3472963130,1553781310&fm=55&app=54&f=JPEG?w=1140&h=640","1.png");
        TestThread2 t2=new TestThread2("https://dss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=3472963130,1553781310&fm=55&app=54&f=JPEG?w=1140&h=640","2.png");
        TestThread2 t3=new TestThread2("https://dss1.baidu.com/6ONXsjip0QIZ8tyhnq/it/u=3472963130,1553781310&fm=55&app=54&f=JPEG?w=1140&h=640","3.png");

    }
}
//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");
        }
    }
}