GUC-9 ReadWriteLock : 读写锁

import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/*
 * 1. ReadWriteLock : 读写锁
 *
 * 写写/读写 需要“互斥”
 * 读读 不需要互斥
 *
 */
public class TestReadWriteLock {

    public static void main(String[] args) {
        ReadWriteLockDemo rw = new ReadWriteLockDemo();

        new Thread(new Runnable() {

            @Override
            public void run() {
                rw.set((int)(Math.random() * 101));
            }
        }, "Write:").start();

        for (int i = 0; i < 100; i++) {
            new Thread(new Runnable() {

                @Override
                public void run() {
                    rw.get();
                }
            }).start();
        }
    }

}

class ReadWriteLockDemo{

    private int number = 0;

    private ReadWriteLock lock = new ReentrantReadWriteLock();

    //读
    public void get(){
        lock.readLock().lock(); //上锁

        try{
            System.out.println(Thread.currentThread().getName() + " : " + number);
        }finally{
            lock.readLock().unlock(); //释放锁
        }
    }

    //写
    public void set(int number){
        lock.writeLock().lock();

        try{
            System.out.println(Thread.currentThread().getName());
            this.number = number;
        }finally{
            lock.writeLock().unlock();
        }
    }
}