谈自定义Exception进行错误处理

    身份验证时，我们常常要返回一个User对象，然而又要知道到底是什么地方错误。我们可以用Exception进行控制！下面是我写的一个例子，你可以加上数据库连接！
public class Login{
    public User validate(String userName,String password) throws InvalidNameException,WrongPasswordException{
        if(userName.equals(\"java\")){
            if(password.equals(\"java\")){
                return new User(userName);
            }else{
                throw new WrongPasswordException();
            }
        }else{
            throw new InvalidNameException();
        }
        //return null;
    }

    public static void main(String[] args){
      Login l=new Login();
        User user=null;
        try{
            user=l.validate(\"javac\",\"java\");
        }catch(InvalidNameException invalidName){
            System.out.println(\"The username is invalid!\");
        }catch(WrongPasswordException wrongPassword){
            System.out.println(\"The password is wrong\");
        }
        if(!(user==null)){
            System.out.println(user.getUserName());
        }
    }
}
class User{
    private String userName;
    public User(String userName){
        this.userName=userName;
    }
    public void setUserName(String userName){
        this.userName=userName;
    }
    public String getUserName(){
        return userName;
    }
}
class InvalidNameException extends Exception{
    public InvalidNameException(){
    }
}
class WrongPasswordException extends Exception{
    public WrongPasswordException(){
    }
}

【责编:Ken】