java ReadWriteLock锁

最新推荐文章于 2025-03-20 14:05:18 发布

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最新推荐文章于 2025-03-20 14:05:18 发布

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分类专栏： java开发基础文章标签： ReadWriteLock java

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本文通过实例探讨了Java中并发编程中的读写锁机制，详细解释了如何使用读写锁来解决线程同步问题，并通过代码展示了实现过程。

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package com.using.weixin.action;

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 WxTest {
	static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

	public static void main(String[] args) throws InterruptedException {
		Data data = new Data();
		//多个线程执行读操作可同时进行
//		 Worker t1 = new Worker(data, true);
//		 Worker t2 = new Worker(data, true);
//		 t1.start();
//		 t2.start();

		//多个线程同时执行执行读写操作时，写操作等待读操作完后才执行
//		Worker t1 = new Worker(data, true);
//		Worker t2 = new Worker(data, false);
//		t1.start();
//		t2.start();
		
		//多个线程同时执行执行读写操作时，读操作等待写操作完后才执行
//		Worker t1 = new Worker(data, false);//写操作
//		Worker t2 = new Worker(data, true);
//		t1.start();
//		t2.start();
		
		//多个线程同时执行执行写操作时，按照先后顺序执行(谁先占用谁先写)
		Worker t1 = new Worker(data, false);//写操作
		Worker t2 = new Worker(data, false);
		t1.start();
		t2.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.get();
			else
				data.set();
		}
	}

	static class Data {
		ReadWriteLock lock = new ReentrantReadWriteLock();
		Lock read = lock.readLock();
		Lock write = lock.writeLock();

		public void set() {
			write.lock();
			System.out.println(Thread.currentThread().hashCode()
					+ " set:begin " + sdf.format(new Date()));
			try {
				Thread.sleep(2000);
				//  
			} catch (Exception e) {

			} finally {
				System.out.println(Thread.currentThread().hashCode()
						+ " set:end " + sdf.format(new Date()));
				write.unlock();
			}

		}

		public int get() {
			read.lock();
			System.out.println(Thread.currentThread().hashCode()
					+ " get :begin " + sdf.format(new Date()));
			try {
				Thread.sleep(2000);
				//  
			} catch (Exception e) {

			} finally {
				System.out.println(Thread.currentThread().hashCode()
						+ " get :end " + sdf.format(new Date()));
				read.unlock();
			}

			return 1;
		}
	}
}