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() { } }
class MyException extends Exception { public MyException() {} public MyException(String msg) { super(msg); } } public class Test { /** * @param args * @throws MyException */ public static void main(String[] args) throws MyException { // TODO Auto-generated method stub int i = 1; if(i == 1 ) { throw new MyException("就是不让 i = 1");
}
}}
class MyException extends Exception { } 最简单的一个Exception 了 哈哈,什么时候用的,直接throw就好了
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()
{ }
}
class MyException extends Exception {
public MyException() {}
public MyException(String msg) {
super(msg);
}
}
public class Test { /**
* @param args
* @throws MyException
*/
public static void main(String[] args) throws MyException {
// TODO Auto-generated method stub
int i = 1;
if(i == 1 )
{
throw new MyException("就是不让 i = 1");
}
}}
最简单的一个Exception 了
哈哈,什么时候用的,直接throw就好了