java5 多线程 锁

 

package java5;

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

public class Test1 {
 public static void main(String[] args) {
  // 创建并发访问的账户
  MyCount myCount = new MyCount("95599200901215522", 10000);
  // 创建一个锁对象
  Lock lock = new ReentrantLock();
  // 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, -4000, lock);
  User u2 = new User("张三他爹", myCount, 6000, lock);
  User u3 = new User("张三他弟", myCount, -8000, lock);
  User u4 = new User("张三", myCount, 800, lock);
  // 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();
 }
}

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，当然有正负之分了
 private Lock myLock; // 执行操作所需的锁对象

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

 public void run() { // 获取锁
  myLock.lock(); // 执行现金业务
  System.out.println(name + "正在操作" + myCount + "账户，金额为" + iocash
    + "，当前金额为" + myCount.getCash());
  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();
 }
}

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 + '}';
 }
}