package com.alioo.lock;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
 *
 */
public class ReadWriteLockDemo {
	static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
	public static void main(String[] args) {
		Data data = new Data();
		Worker t1 = new Worker(data, false);
		//写
		Worker t2 = new Worker(data, true);
		//读
		Worker t3 = new Worker(data, true);
		//读
		t1.start();
		t2.start();
		t3.start();
	}
	static class Worker extends Thread {
		Data data;
		Boolean read;
		public Worker(Data data, Boolean read) {
			this.data = data;
			this.read = read;
		}
		public void run() {
			if (read)
			    data.read(); else
			    data.write();
		}
	}
	static class Data {
		ReadWriteLock lock = new ReentrantReadWriteLock();
		Lock read = lock.readLock();
		Lock write = lock.writeLock();
		public void write() {
			try {
				Thread.sleep(2000);
				//
			}
			catch (Exception e) {
			}
			write.lock();
			System.out.println(Thread.currentThread() + " write:begin "
			     + sdf.format(new Date()));
			try {
				Thread.sleep(5000);
				//
			}
			catch (Exception e) {
			}
			finally {
				System.out.println(Thread.currentThread() + " write:end "
				      + sdf.format(new Date()));
				write.unlock();
			}
		}
		public int read() {
			read.lock();
			System.out.println(Thread.currentThread()+ " read :begin "
			     + sdf.format(new Date()));
			try {
				Thread.sleep(5000);
				//
			}
			catch (Exception e) {
			}
			finally {
				System.out.println(Thread.currentThread() + " read :end "
				      + sdf.format(new Date()));
				read.unlock();
			}
			return 1;
		}
	}
}

read.lock();

Thread[Thread-2,5,main] read :begin 2018-01-22 13:54:16.794
Thread[Thread-1,5,main] read :begin 2018-01-22 13:54:16.794

Thread[Thread-2,5,main] read :end 2018-01-22 13:54:21.795
Thread[Thread-1,5,main] read :end 2018-01-22 13:54:21.795

Thread[Thread-0,5,main] write:begin 2018-01-22 13:54:21.795
Thread[Thread-0,5,main] write:end 2018-01-22 13:54:26.795