多线程编程入门(持续更新)

多线程编程入门(持续更新)

进程：资源分配的基本单位

线程：执行的基本单位（主线程与其他子线程）

实现多线程的过程

创建类➡继承Thread类➡重写run()方法→主线程中调用start()方法

public class Thread01 extends Thread{
    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            System.out.println("子线程"+i);
        }
    }

    public static void main(String[] args) {
        //创建一个线程对象
        Thread01 thread01 = new Thread01();
        //调用start方法开启线程
        thread01.start();


        //主线程
        for (int i = 0; i < 20; i++) {
            System.out.println("主线程"+i);
        }
    }
}

多线程实现同步下载图片

下载commons io 26的jar包，使用下载工具FileUtils进行下载，传入url以及要保存的文件名

public class Thread02 extends Thread{
    private String url;//文件所在地址
    private String name;//保存的文件名

    public Thread02(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("成功下载文件，并保存名为:"+name);
    }

    public static void main(String[] args) {
        //创建三个线程并启动
        Thread02 thread01 = new Thread02("https://dsfs.oppo.com/act/upload/image/20210304/1614824284935215.png","mypicture1.png");
        Thread02 thread02 = new Thread02("https://img-blog.csdnimg.cn/20210719165044136.png","mypicture2.png");
        Thread02 thread03 = new Thread02("https://img-blog.csdnimg.cn/20210719164938900.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDg5MzkwMg==,size_16,color_FFFFFF,t_70","mypicture3.png");

        thread01.start();
        thread02.start();
        thread03.start();
    }

    //创建下载器
    class WebDownloader{
        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出错，download方法出现问题");
            }
        }
    }

}