退出异常 Java答案

【问题标题】：Withdraw Exception Java退出异常 Java
【发布时间】：2013-11-28 04:13:45
【问题描述】：

当我向用户询问要从其余额中提取的金额时，我遇到了问题。我有一个叫做withdraw的方法，我通过了他们的余额。然后我想检查他们想要提取的金额是否小于他们的余额。如果是，我想让用户重试。

到目前为止，它会检查输入，但每次尝试都会得到输出。

public void withdraw (double balance){
System.out.println("How much would you like to withdraw?");
double amount = keyboard.nextDouble();  

try
{
    if(amount > balance)
    {
        throw new IncorrectWithdrawException();
    }
}

catch(IncorrectWithdrawException e)
{
    System.out.println(e.getMessage());
    withdraw(balance);// keeps calling the method for a loop if they keep entering incorrect amount
}

balance = balance-amount;
System.out.println("You have withdrawn "+amount+ " and your new balance is "+balance); }}

输出：

你的余额是多少？ 100 您想提款多少？200 ------错误----- 这不是一个有效的提款金额。你想取多少钱？ 500 ------ERROR----- 这不是一个有效的提款金额。你想取多少钱？ 50

您已提取 50.0，您的新余额为 50.0

我不想要下面的最后两个输出...

您已提取 500.0，新余额为 -400.0 您已提取 200.0，新余额为 -100.0

【问题讨论】：

你的previous problem 解决了吗？如果有，请accept回答。
如果你捕捉到你刚刚在几行前抛出的异常，最好不要一开始就抛出它——使用 if/else 代替！至于你不想在特定情况下出现的打印，再次相应地使用 if/else

标签： java exception

【解决方案1】：

public void withdraw (double balance)
{
  System.out.println("How much would you like to withdraw?");
  double amount = keyboard.nextDouble();  

  try
  {
   if(amount < balance)
   {
    balance = balance-amount;
    System.out.println("You have withdrawn "+amount+ " and your new balance is "+balance);
   }
  else
   throw new IncorrectWithdrawException();
  }
 catch(IncorrectWithdrawException e)
 {
    System.out.println(e.getMessage());
    withdraw(balance);// keeps calling the method for a loop if they keep entering incorrect amount
 }
 }

【讨论】：