谈自定义Exception进行错误处理

文章作者 100test 发表时间 2008:02:01 14:52:38
来源 100Test.Com百考试题网

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(){
}
}