Java lock同步锁使用实例解析

package lock;

/*
方式三：
  Lock锁
synchronized和lock的不同
1.sychronized在执行完相应代码块以后属于自动释放同步监视器，lock需要手动启动同步
建议优先使用lock->同步方法块->同步方法(在方法体之外)

实现Runnable对象被三个线程调用，然后这个对象的run方法里贡献资源操作器被lock上锁了

@author zsben
@create 2020-01-03 23:55
*/

import java.util.concurrent.locks.ReentrantLock;

class Window implements Runnable{

  private int ticket = 100;

  //1.实例化lock
  private ReentrantLock lock = new ReentrantLock(true);//fair=true:公平锁，线程先来后到

  @Override
  public void run() {
    while(true){
      try{
        //2.调用lock方法
        lock.lock();

        if(ticket>0){

          try {
            Thread.sleep(100);
          } catch (InterruptedException e) {
            e.printStackTrace();
          }

          System.out.println(Thread.currentThread().getName()+": "+ticket);
          ticket--;
        }else break;
      }
      finally {
        //3.调用解锁方法
        lock.unlock();
      }
    }
  }
}

public class LockTest {

  public static void main(String[] args) {
    Window w = new Window();

    Thread t1 = new Thread(w);
    Thread t2 = new Thread(w);
    Thread t3 = new Thread(w);

    t1.start();
    t2.start();
    t3.start();

  }
}