java线程学习1

java实现多线程有三种方式：继承Thread类，重写run方法，启动使用start；实现runnable接口，重写run方法；实现callable接口，重写call方法（可以有返回值，也可以抛出异常）

1.多线程实现文件下载利用FileUtils.copyURLtoFile（）

package threadStudy;

import java.io.File;

import java.io.IOException;

import java.net.MalformedURLException;

import java.net.URL;

import org.apache.commons.io.FileUtils;

public class WebDownload {

    public void download(String url,String dest) {

        try {

            FileUtils.copyURLToFile(new URL(url), new File(dest));

        } catch (MalformedURLException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            System.out.println("url is error!");

        }

    }

}

package threadStudy;

public class ThreadDownload extends Thread{

    String url;

    String dest;

    public ThreadDownload(String url,String dest) {

        this.url = url;

        this.dest = dest;

    }

    @Override

    public void run() {

        new WebDownload().download(url, dest);

        System.out.println(dest);

    }

    public static void main(String[] args) {

        ThreadDownload t1 = new ThreadDownload("http://pic-bucket.ws.126.net/photo/0001/2019-06-06/EH0TSVI400AP0001NOS.jpg", "linzhiling.jpg");

        ThreadDownload t2 = new ThreadDownload("http://pic-bucket.ws.126.net/photo/0001/2019-06-06/EH0TSVI500AP0001NOS.jpg", "linzhiling2.jpg");

        ThreadDownload t3 = new ThreadDownload("http://pic-bucket.ws.126.net/photo/0001/2019-06-05/EGTO1O6800AN0001NOS.jpg", "rocket.jpg");

        ThreadDownload t4 = new ThreadDownload("http://pic-bucket.ws.126.net/photo/0001/2019-06-05/EGTLGCTO00AN0001NOS.jpg", "rocket2.jpg");

        t1.start();

        t2.start();

        t3.start();

        t4.start();

    }

}

模拟抢票（同步问题以后解决）

package threadStudy;

public class Tickets implements Runnable {

    /**

     * 使用runnable 实现线程 有利于共享资源

     */

    private int ticketNumber = 100;

    @Override

    public void run() {

        while (true) {

            if (ticketNumber <= 0) {

                break;

            } else {

                try {

                    Thread.sleep(100);  //模拟线程同步问题

                } catch (InterruptedException e) {

                    // TODO Auto-generated catch block

                    e.printStackTrace();

                }

                System.out.println(Thread.currentThread().getName() + "----->" + ticketNumber--);

            }

        }

    }

    public static void main(String[] args) {

        Tickets t = new Tickets();

        System.out.println(Thread.currentThread().getName());

        new Thread(t,"黄牛一").start();

        new Thread(t,"黄牛二").start();

        new Thread(t,"黄牛三").start();

    }

}

巴特西

java线程学习1

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