11.Lock锁

1.创建Lock锁对象的方式：使用实现类ReentrantLock创建Lock对象。

(1)Lock lock=new ReentrantLock();

注：相当于synchronized(this)。

(2)static Lock lock=new ReentrantLock();

注：相当于synchronized(类.class)。

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

public class mysellticket implements Runnable{
    public mysellticket(){
        //测试出来在创建不同对象的时候打印出来的lock对象一样
        System.out.println(lock);
    }
    private static int tickets=10;
    private static Lock lock=new ReentrantLock();
    private int x=5;
    @Override
    public void run() {
        while (x>0) {
            try {
                lock.lock();
                if (x < 0 || x == 0) {//不加这个判断x<=0,结果会多输出两条数据
                    break;
                }
                if (tickets > 0) {
                    try {
                        Thread.sleep(2000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName()+"：正在销售第"+tickets+"张票");
                    tickets--;
                }
            }finally {
                x--;
                lock.unlock();
            }
        }
    }
    public static void main(String[] args) {
        //同一个my对象，可以锁住。
//        mysellticket my = new mysellticket();
//        Thread t1 = new Thread(my, "窗口1");
//        Thread t2 = new Thread(my, "窗口2");
//        t1.start();
//        t2.start();

        //不同一个my，my1对象，不能锁住。
        mysellticket my = new mysellticket();
        mysellticket my1 = new mysellticket();
        Thread t1 = new Thread(my, "窗口1");
        Thread t2 = new Thread(my1, "窗口2");
        t1.start();
        t2.start();

        //注：要是lock对象加上static修饰，则会锁住类
    }
}