一、题目

三个售票员卖30张票

二、代码

1.synchronized版

package com.xxx;

class Ticket{
    private int number = 30;
    public synchronized void sale(){
        if (number > 0){
            number--;
            System.out.println(Thread.currentThread().getName() + "卖了一张票，还剩"+ number +"张票");
        }

    }
}
public class SaleTicket {
    public static void main(String[] args) {
        Ticket ticket = new Ticket();
        new Thread(() -> {
            for (int i = 0;i < 40;i++){
                ticket.sale();
            }
        },"售票员A").start();
        new Thread(() -> {
            for (int i = 0;i < 40;i++){
                ticket.sale();
            }
        },"售票员B").start();
        new Thread(() -> {
            for (int i = 0;i < 40;i++){
                ticket.sale();
            }
        },"售票员C").start();
    }
}

2.Lock版

package com.xxx;

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

class Ticket{
    Lock lock = new ReentrantLock();
    private int number = 30;
    public  void sale(){
        try{
            lock.lock();
            if (number > 0){
                number--;
                System.out.println(Thread.currentThread().getName() + "卖了一张票，还剩"+ number +"张票");
            }
        }finally {
            lock.unlock();
        }
    }
}
public class SaleTicket {
    public static void main(String[] args) {
        Ticket ticket = new Ticket();
        new Thread(() -> {
            for (int i = 0;i < 40;i++){
                ticket.sale();
            }
        },"售票员A").start();
        new Thread(() -> {
            for (int i = 0;i < 40;i++){
                ticket.sale();
            }
        },"售票员B").start();
        new Thread(() -> {
            for (int i = 0;i < 40;i++){
                ticket.sale();
            }
        },"售票员C").start();
    }
}