谈自定义Exception进行错误处理

会计考友 · 发表于 2012-8-4 12:19:50

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(){
}
}

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