这是自JDK5.0开始提供的Java并发包里面的类
下面是关于Java并发锁的测试代码
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package com.jadyer.thread.lock;
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import java.util.concurrent.locks.Lock;
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import java.util.concurrent.locks.ReentrantLock;
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/**
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* LockTest
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* @author 宏宇
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* @create Mar 1, 2012 7:12:04 PM
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*/
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public class LockTest {
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public static void main(String[] args) {
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FoodCenter fc = new FoodCenter();
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new Thread(new ThreadDog(fc, "It is dog`s food")).start();
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new Thread(new ThreadPig(fc, "It is pig`s food")).start();
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}
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}
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class ThreadDog implements Runnable{
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private FoodCenter fc;
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private String foodname;
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public ThreadDog(FoodCenter fc, String foodname){
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this.fc = fc;
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this.foodname = foodname;
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}
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@Override
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public void run() {
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while(true){
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try {
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Thread.sleep(1000);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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fc.getFood(foodname);
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}
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}
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}
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class ThreadPig implements Runnable{
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private FoodCenter fc;
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private String foodname;
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public ThreadPig(FoodCenter fc, String foodname){
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this.fc = fc;
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this.foodname = foodname;
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}
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@Override
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public void run() {
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while(true){
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try {
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Thread.sleep(2000);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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fc.getFood(foodname);
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}
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}
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}
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/**
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* @see =========================================================================================
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* @see java.util.concurrent是JDK5.0开始提供的Java并发包，其子包locks是专门用于处理线程锁的
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* @see java.util.concurrent.locks.Lock较synchronized关键字比，有一个最大的区别，那就是
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* @see Lock可以比synchronized更细粒度的控制锁，体现在try{...}finally{mylock.unlock();}
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* @see =========================================================================================
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* @see Lock有点像公共厕所的门闩，只有正在使用厕所的人，把门闩打开出来了，其它人才可以使用公厕
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* @see Lock比传统线程模型中的synchronized方式更加面向对象。与生活中的锁类似，锁本身也应该是一个对象
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* @see 两个线程执行的代码片段要实现同步互斥的效果，那么这两个线程所使用的必须是同一个Lock对象
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* @see 并且，锁应该位于待操作的资源类的内部方法中，而非线程代码中
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* @see =========================================================================================
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*/
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class FoodCenter {
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Lock mylock = new ReentrantLock(); //创建一个锁
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public void getFood(String name) {
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int len = name.length();
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mylock.lock(); //上锁
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try {
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for (int i = 0; i < len; i++) {
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System.out.print(name.charAt(i));
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}
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System.out.println();
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} finally {
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mylock.unlock(); //解锁
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}
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}
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}
下面是关于Java读写锁的测试代码
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package com.jadyer.thread.lock;
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import java.util.concurrent.locks.ReadWriteLock;
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import java.util.concurrent.locks.ReentrantReadWriteLock;
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/**
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* Java读写锁
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* @see 锁分为读锁和写锁。多个读锁不互斥。读锁与写锁互斥。写锁与写锁互斥。这是由JVM自己控制的
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* @see 如果代码只读数据，可以很多人同时读，但不能同时写，那就上读锁
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* @see 如果代码修改数据，并且不允许同时读，只能一个人写，那就上写锁
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* @see 总之：读的时候上读锁，写的时候上写锁
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*/
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public class ReadWriteLockDemo{
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private Object myData = null;//共享数据，只能有一个线程能写该数据，但可以有多个线程同时读该数据
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ReadWriteLock rwl = new ReentrantReadWriteLock();
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public void get() {
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rwl.readLock().lock(); //读锁
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try {
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System.out.println(Thread.currentThread().getName() + " be ready to read data");
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Thread.sleep((long) (Math.random() * 1000));
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System.out.println(Thread.currentThread().getName() + " have read data : " + myData);
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} catch (InterruptedException e) {
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e.printStackTrace();
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} finally {
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rwl.readLock().unlock();
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}
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}
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public void put(Object data) {
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rwl.writeLock().lock(); //写锁
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try {
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System.out.println(Thread.currentThread().getName() + " be ready to write data");
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Thread.sleep((long) (Math.random() * 1000));
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this.myData = data;
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System.out.println(Thread.currentThread().getName() + " have write data : " + myData);
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} catch (InterruptedException e) {
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e.printStackTrace();
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} finally {
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rwl.writeLock().unlock();
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}
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}
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}
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原文链接： http://blog.csdn.net/hopezhangbo/article/details/7383799