Java 异常处理 练习2

建立exception包，建立Bank类，类中有变量double  balance表示存款,Bank类的构造方法能增加存款，Bank类中有取款的发方法withDrawal(double dAmount),当取款的数额大于存款时,抛出InsufficientFundsException,取款数额为负数，抛出NagativeFundsException,如new Bank(100),表示存入银行100元，当用方法withdrawal(150)，withdrawal(-15)时会抛出自定义异常。

package exception;

public class Bank {

     private double balance;

        public Bank (double balance) {
            super();
            this.balance = balance;
        }
        public void withDrawal(double dAmount)throws InsufficientFundsException,NagativeFundsException
        {
            if(dAmount>balance)
            {
                throw new InsufficientFundsException();
            }
            if(dAmount<0)
            {
                throw new NagativeFundsException();
            }
        }

        public static void main(String[] args){
            Bank t=new Bank (100);
            try{
            t.withDrawal(110);
            }catch(Exception e){
                e.printStackTrace();
            }
            try{
                t.withDrawal(-100);
            }catch(Exception e){
                e.printStackTrace();
            }
        }

}

package exception;

public class NagativeFundsException extends Exception {

    public String getMessage()
     {
         return "取款不能为负数";
     }
}

package exception;

public class InsufficientFundsException extends Exception {

    public String getMessage()
     {
         return "余额不足";
     }
}