lock锁

显式的定义锁

CopyOnWriteArrayList类中也有ReentrantLock(可重入锁)

• //定义lock锁 ReentrantLock lock=new ReentrantLock();

• //加锁 lock.lock();

• //解锁 lock.unlock();

package test2;

import java.util.concurrent.locks.ReentrantLock;

public class TestLock {
    public static void main(String[] args) {

        TestLock2 testLock2=new TestLock2();

        new Thread(testLock2,"小明").start();
        new Thread(testLock2,"小红").start();
        new Thread(testLock2,"小六").start();

    }
}

class TestLock2 implements Runnable{
    int ticket=10;

    //定义lock锁
    private final ReentrantLock lock=new ReentrantLock();

    @Override
    public void run() {
        while(true) {


            //所有锁的unlock要放到try{}finally{}里，不然发生异常返回就丢了unlock了
            try{
                //加锁
                lock.lock();

                if (ticket > 0) {
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName()+"拿到了第"+ticket--+"张票");
                } else {
                    break;
                }
            }finally{
                //解锁
                lock.unlock();
            }

        }
    }
}