3、使用锁机制lock，unlock

package com.lfy.ThreadsSynchronize;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;/** * 1、使用锁机制 * 语法：lock(),unlock()*/public class TicketSellSolution3 extends Thread{    private static int num = 50;        //创建一个锁对象    Lock l = new ReentrantLock();        public TicketSellSolution3(String string) {        super(string);    }        @Override    public void run() {        for(int i = 0 ; i < 50 ;i ++){                l.lock();                try {                    if(num > 0){                      Thread.sleep(10);                      System.out.println(Thread.currentThread().getName()+"卖出一张票，剩余"+(--num)+"张");                    }                } catch (InterruptedException e) {                    e.printStackTrace();                }finally{                    l.unlock();                }        }    }}