TreadAPP-使用线程下载文件

Posted 2020-09-25 lxj666

package main;

/**
 * Created by lxj-pc on 2017/6/27.
 */
public class TreadApp {//volatile 线程间共享变量

    private static  volatile boolean isExit=false;//static成员不能访问非static成员


    public static void main(String[] args) {
        //下载一个文件 启动线程 ，线程池使用,
        //启动线程 下载文件 1.线程自己实现方法
        //多行注释 shift+Ctrl+/
/*      1.  new DownloadTread ("file1").start();
        new DownloadTread ("file2").start();
        new DownloadTread ("file3").start();
        new DownloadTread ("file4").start();*/

/*      2.     new Thread((new DownloadTask("file1"))).start();
           new Thread((new DownloadTask("file2"))).start();
           new Thread((new DownloadTask("file3"))).start();
           new Thread((new DownloadTask("file4"))).start();
           new Thread((new DownloadTask("file5"))).start();*/

        new Thread((new DownloadTask("file1"))).start();
        //主线程休眠2s 执行退出
        try {
            Thread.sleep(Long.parseLong("2000"));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }





        //打印主线程ID
        System.out.println("当前主线程ID："+Thread.currentThread().getId());

        isExit=true;




//       4. new Thread(){//可以Thread直接调用
//            @Override
//            public void run() {
//                super.run();
//            }}.start();

    }






    static class DownloadTask implements Runnable{
    private String url;
    private int currentThreadId=-1;
    public DownloadTask(String url){
        this.url=url;

    }


        @Override
        public void run() {
        //获取当前线程的ID
        // Thread.currentThread().getId()
            currentThreadId = (int) Thread.currentThread().getId();

            System.out.println("下载..."+url+"，线程ID："+currentThreadId+"开始");



            //随机产生5-10s
            int s= (int) (Math.random()*6+5); // [5,10]
            for (int i = 0; i <s ; i++) {
                try {
                    Thread.sleep(Long.parseLong("1000"));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                if(isExit)
                    return;
                 System.out.println(currentThreadId+"已用.."+i+ "秒");
            }

            System.out.println(currentThreadId+"下载完成"+url);
        }
    }



    //类的成员内部类
     static class DownloadTread extends Thread {

        private String url;//文件路径

        public DownloadTread(String url) {

            this.url = url;

        }

        public void run() {
            super.run();//无功能 无作用
            //实现下载文件代码
            //   Thread.getId()  线程里的唯一标识
            System.out.println("正在下载文件" + url + "线程id：" + getId());
            int ms = (int) (Math.random() * 11 + 2) * 1000;//2-12毫秒

            System.out.println(url + "计划完成时间" + ms / 1000 + " 秒");
            try {
                sleep(ms);//线程休眠
            } catch (InterruptedException e) {
                e.printStackTrace();
            }


            System.out.println(url + "文件已经下载完成！");
        }
        
    }
    
}