import java.util.concurrent.ExecutorService; 
import java.util.concurrent.Executors; 
import java.util.concurrent.locks.ReadWriteLock; 
import java.util.concurrent.locks.ReentrantReadWriteLock; 

/** 

* Java线程：锁 

* 

* @author leizhimin 2009-11-5 10:57:29 

*/ 
public  class Test { 
         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 
                ReadWriteLock lock =  new ReentrantReadWriteLock( false); 
                 //创建一个线程池 
                ExecutorService pool = Executors.newFixedThreadPool(2); 
                 //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,  false); 
                User u2 =  new User( "张三他爹", myCount, 6000, lock,  false); 
                User u3 =  new User( "张三他弟", myCount, -8000, lock,  false); 
                User u4 =  new User( "张三", myCount, 800, lock,  false); 
                User u5 =  new User( "张三他爹", myCount, 0, lock,  true); 
                 //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); 
                pool.execute(u5); 
                 //关闭线程池 
                pool.shutdown(); 
        } 
} 

/** 

* 信用卡的用户 

*/ 
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 ReadWriteLock myLock;                 //执行操作所需的锁对象 
         private  boolean ischeck;         //是否查询 

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

         public  void run() { 
                 if (ischeck) { 
                         //获取读锁 
                        myLock.readLock().lock(); 
                        System.out.println( "读：" + name +  "正在查询" + myCount +  "账户，当前金额为" + myCount.getCash()); 
                         //释放读锁 
                        myLock.readLock().unlock(); 
                }  else { 
                         //获取写锁 
                        myLock.writeLock().lock(); 
                         //执行现金业务 
                        System.out.println( "写：" + 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( "写：" + name +  "操作" + myCount +  "账户成功，金额为" + iocash +  "，当前金额为" + myCount.getCash()); 
                         //释放写锁 
                        myLock.writeLock().unlock(); 
                } 
        } 
} 

/** 

* 信用卡账户，可随意透支 

*/ 
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 + 
                                '}'; 
        } 
}

写：张三正在操作MyCount{oid='95599200901215522', cash=10000}账户，金额为-4000，当前金额为10000 
写：张三操作MyCount{oid='95599200901215522', cash=6000}账户成功，金额为-4000，当前金额为6000 
写：张三他弟正在操作MyCount{oid='95599200901215522', cash=6000}账户，金额为-8000，当前金额为6000 
写：张三他弟操作MyCount{oid='95599200901215522', cash=-2000}账户成功，金额为-8000，当前金额为-2000 
写：张三正在操作MyCount{oid='95599200901215522', cash=-2000}账户，金额为800，当前金额为-2000 
写：张三操作MyCount{oid='95599200901215522', cash=-1200}账户成功，金额为800，当前金额为-1200 
读：张三他爹正在查询MyCount{oid='95599200901215522', cash=-1200}账户，当前金额为-1200 
写：张三他爹正在操作MyCount{oid='95599200901215522', cash=-1200}账户，金额为6000，当前金额为-1200 
写：张三他爹操作MyCount{oid='95599200901215522', cash=4800}账户成功，金额为6000，当前金额为4800 

Process finished with exit code 0