bank.java

该源码实现了一个银行类,当取钱数目大于卡中的余额时,会触发一个异常.

//余额不足异常 
class BalanceLackException extends Exception
{ 
    public String toString()
   { 
     return "BalanceLackException:余额不足!"; 
   } 
} 



public class Bank
{ 
   public int balance; //余额 
   private static boolean exceptionSign; //异常标志,用于判断是否有异常产生 

   public Bank(int balance)
  { 
    this.balance=balance; 
    this.exceptionSign=false; 
   } 

   public int getBalance ()
  {  
    return this.balance; 
  } 

   public void fetchFund(int money) throws
    BalanceLackException{ 
      if (money>balance) throw new BalanceLackException(); //引发余额不足异常 
      balance -= money; 
   } 

   public static void main(String[] args) 
   {
      Bank bank =new Bank(1000); 
      try{ 
           bank.fetchFund(500); 
           bank.fetchFund(1000); 
           bank.fetchFund(2500); 
         } 
     catch(BalanceLackException e) 
     { 
          exceptionSign = true;
          System.out.println(e); 
      } 

     finally{ 
             if (exceptionSign) System.out.println("有错误产生,操作未完成!"); 
             else System.out.println("操作完成!目前的余额为:"+bank.getBalance()); 
             } 
    } 
}