多线程学习-坏人

学习原：来自哔哩哔哩：狂神

1.学习 Runnable

2.问题

1.问题1

java代码：

package com.sunweihao.example;
//多个线程同时操作一个对象
//拍电影的例子，先到先拍片
public class TestThread4 implements Runnable {
    //有十部电影
    private int ticketNums=10;
    @Override
    public void run() {
        while (true){
            if (ticketNums<=0){
                break;
            }
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName()+"---->拍了第"+ticketNums--+"剧");
        }
    }
    public static void main(String[] args) {
        TestThread4 ticket=new TestThread4();
        new Thread(ticket,"颇多野老师").start();
        new Thread(ticket,"苍井空老湿").start();
        new Thread(ticket,"老司机").start();
    }
}

打印结果：

问题分析：

解决办法：

加锁

package com.sunweihao.example;
//多个线程同时操作一个对象
//拍电影的例子
public class TestThread4Improve implements Runnable {
    //有十部电影
    private int ticketNums=10;
    @Override
    public void run() {
        play();
    }

    private synchronized void  play() {
        while (true){
            if (ticketNums<=0){
                break;
            }
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName()+"---->拍了第"+ticketNums--+"剧");
        }
    }

    public static void main(String[] args) {
        TestThread4Improve ticket=new TestThread4Improve();
        new Thread(ticket,"颇多野老师").start();
        new Thread(ticket,"苍井空老湿").start();
        new Thread(ticket,"老司机").start();
    }
}

结果：

2.Thread下载

步骤：

1.导包

2.代码：下载文件

package com.sunweihao.example;

import org.apache.commons.io.FileUtils;

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

public class TestThread2 extends Thread {
    private String url;
    private String name;
    public TestThread2(String url,String name){
        this.url=url;
        this.name=name;
        //hhh
    }
    @Override
    public void run() {
        WebDownloader webDownloader=new WebDownloader();
        webDownloader.downloader(url,name);
        System.out.println("下载了文件名为："+name);
    }

    public static void main(String[] args) {
        TestThread2 testThread1=new TestThread2("https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=3620297292,2452146774&fm=26&gp=0.jpg","苍井空老师");
        TestThread2 testThread2=new TestThread2("https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=3620297292,2452146774&fm=26&gp=0.jpg","颇多野老师");
        TestThread2 testThread3=new TestThread2("https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=3620297292,2452146774&fm=26&gp=0.jpg","孙伟豪老师");
        testThread1.start();
        testThread2.start();
        testThread3.start();
    }
}
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，download方法出现错误");
        }
    }
}

3.生产消费者模式

展示图

1.有个共同的操作

这里共同操作是TV
生产者：演员

class Player extends Thread{
    TV tv;
    public Player(TV tv){
        this.tv=tv;
    }
    @Override
    public void run() {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        for (int i = 0; i < 20; i++) {
            if (i%2==0) {
                this.tv.play("快乐大本营播放中");
            }else {
                this.tv.play("抖音：记录美好生活");
            }
        }
    }
}

消费者：观众

class Watcher extends Thread{
    TV tv;
    public Watcher(TV tv){
        this.tv=tv;
    }
    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            tv.watch();
        }
    }
}

他们共同看TV

class TV{
    //演员表演，观众等待T
    //观众观看，演员等待F
    String voice;//表演的节目
    boolean flag=true;
    //表演
    public synchronized void play(String voice){
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }//休眠
        if (!flag) {
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }//等待
        }
        System.out.println("演员表演了："+voice);
        //通知观众观看
        this.notifyAll();//通知唤醒
        this.voice=voice;
        this.flag=!this.flag;
    }
    //观看
    public synchronized void watch(){
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }//休眠
        if (flag) {
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }//等待
        }
        System.out.println("观看了："+voice);
        //通知演员表演
        this.notifyAll();
        this.flag=!this.flag;
    }
}

关键代码介绍

1.this.wait()会导致休眠
2.this.notifyAll();//通知其他线程唤醒
3.notify();//通知一条线程唤醒

全部代码

package com.sunweihao.gaoji;
//测试生产者消费者问题2，信号灯法，标志位解决
public class TestPc2 {
    public static void main(String[] args) throws Exception {
        TV tv=new TV();
        new Player(tv).start();
        new Watcher(tv).start();
    }
}
//生产者-演员
class Player extends Thread{
    TV tv;
    public Player(TV tv){
        this.tv=tv;
    }
    @Override
    public void run() {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        for (int i = 0; i < 20; i++) {
            if (i%2==0) {
                this.tv.play("快乐大本营播放中");
            }else {
                this.tv.play("抖音：记录美好生活");
            }
        }
    }
}
//消费者-观众
class Watcher extends Thread{
    TV tv;
    public Watcher(TV tv){
        this.tv=tv;
    }
    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            tv.watch();
        }
    }
}
//产品-节目
class TV{
    //演员表演，观众等待T
    //观众观看，演员等待F
    String voice;//表演的节目
    boolean flag=true;
    //表演
    public synchronized void play(String voice){
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }//休眠
        if (!flag) {
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }//等待
        }
        System.out.println("演员表演了："+voice);
        //通知观众观看
        this.notifyAll();//通知唤醒
        this.voice=voice;
        this.flag=!this.flag;
    }
    //观看
    public synchronized void watch(){
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }//休眠
        if (flag) {
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }//等待
        }
        System.out.println("观看了："+voice);
        //通知演员表演
        this.notifyAll();
        this.flag=!this.flag;
    }
}