Java并发学习之十五——使用读写锁同步数据访问

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读写锁重要的是写锁的使用，只用一个入口。

下面是读写锁使用的例子

package chapter2;import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock;public class PricesInfo {private int price1;private int price2;private ReadWriteLock lock;public PricesInfo(){price1 = 1;price2 = 1;lock = new ReentrantReadWriteLock();}public int getPrice1() {lock.readLock().lock();int value = price1;lock.readLock().unlock();return value;}public void setPrice1(int price1) {this.price1 = price1;}public int getPrice2() {lock.readLock().lock();int value = price2;lock.readLock().unlock();return value;}public void setPrice2(int price2) {this.price2 = price2;}public void setPrices(int price1,int price2){lock.writeLock().lock();this.price1 = price1;this.price2 = price2;lock.writeLock().unlock();}}

package chapter2;public class Reader implements Runnable{private PricesInfo pricesInfo;public Reader(PricesInfo pricesInfo){this.pricesInfo = pricesInfo;}@Overridepublic void run() {for(int i=0;i<10;i++){System.out.printf("%s:Price 2:%d\n", Thread.currentThread().getName(),pricesInfo.getPrice2());System.out.printf("%s:Price 1:%d\n", Thread.currentThread().getName(),pricesInfo.getPrice1());}}}

package chapter2;import java.util.Random;public class Writer implements Runnable{private PricesInfo pricesInfo;public Writer(PricesInfo pricesInfo){this.pricesInfo = pricesInfo;}@Overridepublic void run() {for(int i=0;i<3;i++){int p1 = new Random().nextInt(47);int p2 = new Random().nextInt(47)*10;System.out.println("Writer:Attempt to modify the prices."+p1+"    price2:"+p2);pricesInfo.setPrices(p1, p2);System.out.println("Writer:Prices have been modified."+p1+"    price2:"+p2);try {Thread.sleep(2);} catch (Exception e) {// TODO: handle exception}}}}

package chapter2;public class Main6 {/** * <p> * </p> * @author zhangjunshuai * @date 2014-9-17 上午11:17:50 * @param args */public static void main(String[] args) {PricesInfo pricesInfo = new PricesInfo();Reader reader[] = new Reader[5];Thread threadsReader[] = new Thread[5];for (int i = 0; i < threadsReader.length; i++) {reader[i] = new Reader(pricesInfo);threadsReader[i]=new Thread(reader[i]);}Writer writer = new Writer(pricesInfo);Thread threadWriter = new Thread(writer);for (int i = 0; i < threadsReader.length; i++) {threadsReader[i].start();}threadWriter.start();}}

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