变量线程安全之ReentrantLock

package com.xf.lock;


import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;


public class ReentrantLockTest {
 /**
  * 用于控制账户安全的锁对象，保证账户只有一把锁
  */
 private static final Lock myLock = new ReentrantLock();
 static class User implements Runnable {
  private String name; // 用户名
  private MyCount myCount; // 所要操作的账户
  private int iocash; // 操作的金额，有正负之分了


  public User(String name, MyCount myCount, int iocash) {
   this.name = name;
   this.myCount = myCount;
   this.iocash = iocash;
  }


  public void run() {
   // 获取锁
   myLock.lock();
   // 执行现金业务
   myCount.setCash(myCount.getCash() + iocash);
   System.out.println(name + "操作" + myCount + "账户成功，金额为" + iocash
     + "，当前金额为" + myCount.getCash());
   // 释放锁，否则别的线程没有机会执行了
   myLock.unlock();
  }
 }


 /**
  * 信用卡账户，可随意透支
  */
 static class MyCount {
  private String oid; // 账号
  private int cash; // 账户余额


  MyCount(String oid, int cash) {
   this.oid = oid;
   this.cash = cash;
  }


  public String getOid() {
   return oid;
  }


  public void setOid(String oid) {
   this.oid = oid;
  }


  public int getCash() {
   return cash;
  }


  public void setCash(int cash) {
   this.cash = cash;
  }


  @Override
  public String toString() {
   return "MyCount{" + "oid='" + oid + '\'' + ", cash=" + cash + '}';
  }
 }


 /**
  * 测试类
  */
 static class Test {
  public static void main(String[] args) {
   // 创建并发访问的账户
   MyCount myCount = new MyCount("张三的账户", 10);
   // 创建一个线程池
   ExecutorService pool = Executors.newCachedThreadPool();
   // 创建一些并发访问用户，一个信用卡，存的存，取的取，好热闹啊
   User u1 = new User("张三", myCount, -4);
   User u2 = new User("李四", myCount, 6);
   User u3 = new User("王五", myCount, -8);
   User u4 = new User("赵六", myCount, 6);
   // 在线程池中执行各个用户的操作
   pool.execute(u1);
   pool.execute(u2);
   pool.execute(u3);
   pool.execute(u4);
   // 关闭线程池
   pool.shutdown();
  }
 }


}