在多线程开发中，经常会出现一种情况，我们希望读写分离。就是对于读取这个动作来说，可以同时有多个线程同时去读取这个资源，但是对于写这个动作来说，只能同时有一个线程来操作，而且同时，当有一个写线程在操作这个资源的时候，其他的读线程是不能来操作这个资源的，这样就极大的发挥了多线程的特点，能很好的将多线程的能力发挥出来。
在Java中，ReadWriteLock这个接口就为我们实现了这个需求，通过他的实现类ReentrantReadWriteLock我们可以很简单的来实现刚才的效果，下面我们使用一个例子来说明这个类的用法。
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package com.bird.concursey.charpet3;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class PricesInfo {
private double price1;
private double price2;
private ReadWriteLock lock;
public PricesInfo() {
price1 = 1.0;
price2 = 2.0;
lock = new ReentrantReadWriteLock();
}
public double getPrice1() {
//读取资源锁定
lock.readLock().lock();
double value = price1;
lock.readLock().unlock();
return value;
}
public double getPrice2() {
lock.readLock().lock();
double value = price2;
lock.readLock().unlock();
return value;
}
public void setPrices(double price1, double price2) {
lock.writeLock().lock();
this.price1 = price1;
this.price2 = price2;
lock.writeLock().unlock();
}
}
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下面是读和写两个不同的类
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package com.bird.concursey.charpet3;
public class Reader implements Runnable {
private PricesInfo pricesInfo;
public Reader(PricesInfo pricesInfo) {
this.pricesInfo = pricesInfo;
}
@Override
public void run() {
for (int i = 0; i < 10; i++) {
System.out.printf("%s: Price 1: %f\n", Thread.currentThread()
.getName(), pricesInfo.getPrice1());
System.out.printf("%s: Price 2: %f\n", Thread.currentThread()
.getName(), pricesInfo.getPrice2());
}
}
}
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package com.bird.concursey.charpet3;
public class Writer implements Runnable {
private PricesInfo pricesInfo;
public Writer(PricesInfo pricesInfo) {
this.pricesInfo = pricesInfo;
}
@Override
public void run() {
for (int i = 0; i < 3; i++) {
System.out.printf("Writer: Attempt to modify the prices.\n");
pricesInfo.setPrices(Math.random() * 10, Math.random( ) * 8);
System.out.printf("Writer: Prices have been modified.\n");
try {
Thread.sleep(2);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
PricesInfo pricesInfo = new PricesInfo();
Reader readers[] = new Reader[5];
Thread threadsReader[] = new Thread[5];
for (int i = 0; i < 5; i++){
readers[i] = new Reader(pricesInfo);
threadsReader[i] = new Thread(readers[i]);
}
Writer writer = new Writer(pricesInfo);
Thread threadWriter = new Thread(writer);
for (int i = 0; i < 5; i++){
threadsReader[i].start();
}
threadWriter.start();
}
}
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总结
以上就是本文关于Java多线程之readwritelock读写分离的实现代码的全部内容，希望对大家有所帮助。有什么问题可以随时留言，小编会及时回复大家的。感谢朋友们对服务器之家网站的支持。
原文链接：http://blog.csdn.net/a352193394/article/details/39405287#comments