自定义“无效名字异常”

 1.编译时异常，直接继承Exception

 2.运行时异常，直接继承RuntimeException

public class IllegalNameException extends Exception{//编译时异常//public class IllegalNameException extends RuntimeException{//运行时异常       public IllegalException(){    }    public IllegalException(String msg){        super(msg);    }}//定义一个消费者类public class CustomerService{    public void register(string name)throws IllegalException{        if(name.length()<6){            //异常            //创建异常对象            IllegalException e=new IllegalException("用户名长度不能少于六位");            throw e;            //throw IllegalException("用户名长度不能少于六位");        }        //如果执行到此处，说明用户名是合法的。        System.out.println("用户名合法，注册成功！");    }}//测试类public class Test{    public static void main(String[] args){        String name="nihao";        CustomerService cs=new CustomerService();        try{        cs.register("nihao");        }catch(IllegalNameException e){             System.out.println(e.getMessage());        }            }}