同一把锁

 1 public class SynchronizedClass extends Thread{
 2     private Account account;
 3     private double drawbalance;
 4     Object obj;
 5     public SynchronizedClass(String name,Account account,double drawbalance,Object obj){
 6         super(name);
 7         this.account=account;
 8         this.drawbalance=drawbalance;
 9         this.obj=obj;
10         //start();
11     }
12     public void run(){
13         try{sleep(100);}catch(Exception e){}
14         synchronized(obj){
15             if(drawbalance>account.getBalance()){
16                 System.out.println("余额不足！");
17             }else{
18                 System.out.println("吐钱成功！");
19                 try{
20                     sleep(100);
21                     System.out.println("取钱："+drawbalance);
22                     account.setBalance(account.getBalance()-drawbalance);
23                     System.out.println("余额为："+account.getBalance());
24                 }catch(Exception e){
25                     System.out.println(e);
26                 }
27             }
28         }
29         
30         
31     }
32     public static void main(String[] args){
33     
34         Object o=new Object();//传到了两个线程中，保证了是同一个锁。
35         Account a=new Account("刘腾",100000);
36         new SynchronizedClass("A线程",a,100000,o).start();
37         new SynchronizedClass("B线程",a,10000,o).start();
38     }    
39 }
40 
41 //账户
42 class Account {
43     private String name;
44     private double balance;
45     public Account(){}
46     public Account(String name,double balance){
47         this.name=name;
48         this.balance=balance;
49     }
50     public void setName(String name){
51         this.name=name;
52     }
53     public void setBalance(double balance){
54         this.balance=balance;
55     }
56     public String getName(){
57         return name;
58     }
59     public double getBalance(){
60         return balance;
61     }
62     
63     /*
64     public boolean equals(Object obj){
65         if(this==obj)return true;
66         if(obj==null)return false;
67         if(getClass()!=obj.getClass())return false;
68         Account other =(Account) obj;
69         if(other.name==name&&other.balance==balance)return true;
70         else return false;
71     }
72     */
73 }