多线程：购票小案例

1.同步代码块

public class Tickects1 implements Runnable{
    //共享数据
    private int ticket=100;
    //创建锁对象
    private Object obj=new Object();
    public void run() {
        while(true){
            //同步代码块
            synchronized(obj){
                //可能会发生线程安全问题代码
                if(ticket>0){
                    try {
                        Thread.sleep(500);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName()+"售出了第"+ticket--+"张票");
                }
            }
        }
    }
}

public class Demo01 {
    public static void main(String[] args) {
        Tickects1 t=new Tickects1();
        Thread t1=new Thread(t,"万达官方");
        Thread t2=new Thread(t,"淘票票");
        Thread t3=new Thread(t,"现场售票");
        t1.start();
        t2.start();
        t3.start();
    }
}

2.同步方法

public class Tickects2 implements Runnable{
    //共享数据
    private int ticket=100;
    public void run() {
        while(true){
            sale();
        }
    }

    //同步方法(内置锁对象this)
    public synchronized void sale(){
        if(ticket>0){
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName()+"售出了第"+ticket--+"张票");
        }
    }
}

public class Demo01 {
    public static void main(String[] args) {
        Tickects2 t=new Tickects2();
        Thread t1=new Thread(t,"万达官方");
        Thread t2=new Thread(t,"淘票票");
        Thread t3=new Thread(t,"现场售票");
        t1.start();
        t2.start();
        t3.start();
    }
}

3.Lock接口

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class Tickects3 implements Runnable{
    //共享数据
    private int ticket=100;
    //Lock接口实现类对象
    private Lock lock=new ReentrantLock();
    public void run() {
        while(true){
            //获取锁
            lock.lock();
            if(ticket>0){
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+"售出了第"+ticket--+"张票");
            }
            //释放锁
            lock.unlock();
        }
    }
}

public class Demo01 {
    public static void main(String[] args) {
        Tickects3 t=new Tickects3();
        Thread t1=new Thread(t,"万达官方");
        Thread t2=new Thread(t,"淘票票");
        Thread t3=new Thread(t,"现场售票");
        t1.start();
        t2.start();
        t3.start();
    }
}