首页 > 代码库 > 秒杀多线程第十四篇 读者写者问题继 读写锁SRWLock （续）
秒杀多线程第十四篇 读者写者问题继 读写锁SRWLock （续）
java 包实现了读写锁的操作：
package com.multithread.readwritelock;import java.util.concurrent.CountDownLatch;import java.util.concurrent.Executor;import java.util.concurrent.Executors;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import com.multithread.main.ExampleInterface;import com.multithread.readwrite.WriteThread;public class ReadWriteLockExample extends ExampleInterface { public ReadWriteLock mReadwriteLock = new ReentrantReadWriteLock(false); public File mFile = null; public int mCash = 10000; public CountDownLatch mLatchDown = new CountDownLatch(6); private boolean mStopedFlag = false; @Override public void startDemo() { // TODO Auto-generated method stub mFile = new File("H:\\Project\\SST\\123.txt"); try { mFile.createNewFile(); Executor mEcecutor = Executors.newFixedThreadPool(2 + 4); mEcecutor.execute(new Reader("Reader1")); mEcecutor.execute(new Reader("Reader2")); mEcecutor.execute(new Reader("Reader3")); mEcecutor.execute(new Reader("Reader4")); mEcecutor.execute(new Writer("Writer1", 2000)); mEcecutor.execute(new Writer("Writer2", -3000)); mLatchDown.await(); System.out.println("[startDemo]" + "Demo down"); } catch (IOException | InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public class Reader extends Thread { public String name = null; boolean flag = true; private int index = 0; public Reader(String name) { this.name = name; } @Override public void run() { while (flag) { try { mReadwriteLock.readLock().lock(); System.out.println("[Reader]" + name + "start"); Thread.sleep((long) (Math.random() * 100)); if (!mStopedFlag) { System.out.println("[Reader]" + name + "get mcash now:" + mCash); } else { flag = false; } Thread.sleep((long) (Math.random() * 100)); System.out.println("[Reader]" + name + "down"); mReadwriteLock.readLock().unlock(); Thread.sleep((long) (Math.random() * 1000)); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } mLatchDown.countDown(); } } public class Writer extends Thread { public String name = null; boolean flag = true; private int index = 0; private int cash = 0; public Writer(String name, int addcash) { this.name = name; this.cash = addcash; } @Override public void run() { System.out.println("[Writer]" + name + "start"); while (flag) { try { mReadwriteLock.writeLock().lock(); System.out.println("[Writer]" + name + "start"); Thread.sleep((long) (Math.random() * 100)); int oldcash = mCash; if (mCash <= 0) { flag = false; mStopedFlag = true; } else { mCash += cash; System.out.println("[Writer]" + name + "operator cash old:" + oldcash + " To:" + mCash); } Thread.sleep((long) (Math.random() * 100)); System.out.println("[Writer]" + name + "down"); mReadwriteLock.writeLock().unlock(); Thread.sleep((long) (Math.random() * 1000)); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } mLatchDown.countDown(); } }}
读写锁的特点就是：
1.写者与读者是互斥的
2.每个写者之间是互斥的
3.读者之间可以同时进行
秒杀多线程第十四篇 读者写者问题继 读写锁SRWLock （续）
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