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 { double balance; public Bank(double balance) { } public void withDrawal(double dAmount) throws Exception { if(dAmount>balance) { throw new InsufficientFundsException(); } if(dAmount<0) { throw new NagativeFundsException(); } balance =balance-dAmount; } }
package exception; public class InsufficientFundsException extends Exception { @Override public String getMessage() { // TODO 自动生成的方法存根 return "余额不足！"; } }
package exception; public class NagativeFundsException extends Exception { @Override public String getMessage() { // TODO 自动生成的方法存根 return "取款数不能为负数"; } }
package exception; public class Test1 { public static void main(String[] args) { // TODO 自动生成的方法存根 Bank b=new Bank(100); try{ b.withDrawal(150); } catch (Exception e) { System.out.println(e.getMessage()); } try{ b.withDrawal(-15); } catch(Exception e) { System.out.println(e.getMessage()) ; } } }
原文：http://www.cnblogs.com/jskbk/p/5538121.html