多线程——Runnable接口，龟兔赛跑

下载图片

使用common-io-2.2 jar包下载图片

1. 先下载jia包，
2. 解压后粘贴到当前目录下，
3. 在将其添加到类库中就可以使用了

package ThreadDemo;

import org.apache.commons.io.FileUtils;

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

//联系Thread实现多线程同步下载图片
public class ThreadDemo01 extends Thread {
    
    private String url;  //网络图片的地址
    private String name;//保存的文件名

    public ThreadDemo01(String url, String name) {
    
        this.url = url;
        this.name = name;
    }

    //下载图片线程的执行体
    @Override
    public void run() {
    
        webDownLoader web=new webDownLoader();
        web.downloader(url,name);
        System.out.println("下载了文件名为"+name);
    }

    public static void main(String[] args) {
    
        ThreadDemo01 th1=new ThreadDemo01("https://img2.baidu.com/it/u=1814268193,3619863984&fm=253&app=138&size=w931&n=0&f=JPEG&fmt=auto?sec=1658682000&t=d20c88a4eebf882f4f8950f8613ac1b4","n.jpg");
        ThreadDemo01 th2=new ThreadDemo01("https://img2.baidu.com/it/u=1814268193,3619863984&fm=253&app=138&size=w931&n=0&f=JPEG&fmt=auto?sec=1658682000&t=d20c88a4eebf882f4f8950f8613ac1b4","m.jpg");
        ThreadDemo01 th3=new ThreadDemo01("https://img2.baidu.com/it/u=1814268193,3619863984&fm=253&app=138&size=w931&n=0&f=JPEG&fmt=auto?sec=1658682000&t=d20c88a4eebf882f4f8950f8613ac1b4","p.jpg");

        th1.start();
        th2.start();
        th3.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"+"downLoader出现问题");
                }
            }
        }
}

Runnable接口的使用

1. 实现接口Runnable具有多线程能力
2. 启动线程:传入对象+Thread对象.start();
3. 推荐使用：避免了单继承的局限性，灵活方便，方便同一个对象被多个线程使用

package RunnableStudy;
//创建线程方式二：实现Runnable接口，重写run方法，指向线程需要丢入runnable接口实现类
//调用start
public class Demo01 implements Runnable{
    
    public static void main(String[] args) {
    
        //创建runnable接口的实现类对象
        Demo01 demo=new Demo01();

        //创建线程对象，通过线程对象来开启我们的线程
       // Thread thread = new Thread(demo);
      // thread.start();

        //两行结合
        new Thread(demo).start();

        for (int i = 0; i < 1200; i++) {
    
            System.out.println("我在听歌");
        }
    }
    
    @Override
    public void run() {
    
        for (int i = 0; i < 200; i++) {
    
            System.out.println("我在学习");
        }
    }
}

龟兔赛跑

package RunnableStudy;

public class Race implements Runnable {
    

    private static  String winner;

    public static void main(String[] args) {
    

        Race race=new Race();
        new Thread(race,"乌龟").start();
        new Thread(race,"兔子").start();
    }

    @Override
    public void run() {
    
        for (int i = 0; i <=100; i++) {
    
            //模拟兔子休息
            if (Thread.currentThread().getName().equals("兔子")&&i%10==0){
    
                try {
    
                    Thread.sleep(1);
                } catch (InterruptedException e) {
    
                    e.printStackTrace();
                }
            }
            //判断比赛是否结束
            boolean flag=GameOver(i);
            //比赛结束了停止程序
            if(flag){
    
                break;
            }
            System.out.println(Thread.currentThread().getName()+"跑了"+i+"步");

        }
    }
    private boolean GameOver(int steps){
    
     //判断是否有胜利者
     if(winner!=null){
    //已经存在胜利者，比赛结束
         return true;
     }else if(steps>=100){
    
         winner=Thread.currentThread().getName();
         System.out.println("获胜者是"+winner);
         return true;
        }
     return false;
    }
}