Thread: Username/Password Different Classes Java program help

I have to create two different classes one for the username and one for the password. Im going to focus on the username first. So the username will be a valid email address meaning the username should have the '@' symbol embedded within the submitted string somewhere. It should also have the domain referencer (the '.' character) and the only acceptable domains should be .com, .edu, .org, .mil, and .gov for now.So my program should check to see if these symbols exist and the '.' is indeed the fourth charcacter from the end of the string. Please I need help getting started. I am new to java and please anything would help. I tried looking on how to do it but no luck so if anyone would help. Explain how and why so i can understand it. Thanks in advance.

Hi,

You can validate email address using regular expression. Google it and you will be able to find it.

I think you just need one class, ie: User
make 2 variable username and password as String
for username (email) validation,
I think you can go this way,
you can extract the username variable to validate
1 @
2 .com, .org, etc

you can user chartAt(int index) to get the chart in username.
simply use looping operation to get all char or string u need.
ie: for (int i=0;i<username.length():i++){
// extract the char/string that you need by using charAt
}

if the extraction process is done..
then you can validate for case 1 and case 2.

Okay so far I have this but i am not getting the right results as wanted. Please look the code and see what im doing wrong.

 
import java.util.Scanner; // Imports the Scanner class to get Keyboard Inputs
 
		class ValidateUser{
 
		public static void main (String [] args) {
 
		String inputUserName; // Creates the userName variable
 
		Scanner input = new Scanner (System.in); // Creates a new Scanner
 
		System.out.print("Username: "); // Prints the word "Username" to the screen
		inputUserName = input.next(); // Gets the user input for the username
 
		System.out.println(UserCheck(inputUserName)); // Calls the UserCheck Method
		System.out.println("");
 
		main(args); // re-runs the program (Allows for multiple tests)
		}
 
		public static String UserCheck (String Username) {
 
		String result = "Valid Username"; // Sets the initial result as valid
		int atLoc = 0; // Sets initial (@) location to be 0
		int perLoc = 0; // Sets initial period location to be 0
		int atCount = 0;// Keeps track of the number of (@) symbols
		int perCount = 0; // Keeps track of the number of periods
 
		for (int x =0; x < Username.length(); x++) {
		if ((Username.charAt(x) >= 48 && Username.charAt(x) <= 57) || (Username.charAt(x) >= 65 && Username.charAt(x) <= 90) 
				|| (Username.charAt(x) >= 97 && Username.charAt(x) <= 122) || (Username.charAt(x) == 64) ||
				(Username.charAt(x) == 46) || (Username.charAt(x) == 95)) { //Keep the Username } else { result = "Username Contains Invalid Character!"; //Checks that password contains only letters and numbers } if (Username.charAt(x) == 64) { //Finds the location of the (@) symbol atLoc = x; //and counts the number of (@) symbols in username atCount++;
		} if (Username.charAt(x) == 46) { 
			result = "valid";//Finds the location of the period perLoc = x; //and counts the number of periods in username perCount++;
		}
		} // Ends the for loop
 
		if ((atLoc < 1) || (perLoc < 1) || (perLoc == Username.length()-1)) { //Checks that email contains a period and an (@) symbol and
		result = "Not a valid email address"; //that they are not in the first or last position in the Username.
		}
 
		if (perLoc < atLoc) {
		result = "Not a valid email address"; //Checks that the (@) symbol follows the period in the username
		}
 
		if ((atCount > 1) || (perCount > 1)) { //Checks that there is only one (@) symbol and one period in a username
		result = "Not a vaild email address";
		}
 
		if ((perLoc - atLoc) <= 1) {
		result = "Not a vaild email address";
 
		}
		return (result);// Returns the value of "result"
 
		} // Ends the UserCheck method
		}//Ends the ValidateUser Class

OUTPUT:

Username: tom@gmail.com
Not a vaild email address
 
Username: Ij@@.com
Not a vaild email address
 
Username: Jess@hotmail.com
Not a vaild email address
 
Username:

I keep getting "Not a valid email adress" I am not sure why. PLease help

Okay I did that and found out the last one that says Not a valid email address is the one that always pops up in the output.

import java.util.Scanner; // Imports the Scanner class to get Keyboard Inputs
 
		class ValidateUser{
 
		public static void main (String [] args) {
 
		String inputUserName; // Creates the userName variable
 
		Scanner input = new Scanner (System.in); // Creates a new Scanner
 
		System.out.print("Username: "); // Prints the word "Username" to the screen
		inputUserName = input.next(); // Gets the user input for the username
 
		System.out.println(UserCheck(inputUserName)); // Calls the UserCheck Method
		System.out.println("");
 
		main(args); // re-runs the program (Allows for multiple tests)
		}
 
		public static String UserCheck (String Username) {
 
		String result = "Valid Username"; // Sets the initial result as valid
		int atLoc = 0; // Sets initial (@) location to be 0
		int perLoc = 0; // Sets initial period location to be 0
		int atCount = 0;// Keeps track of the number of (@) symbols
		int perCount = 0; // Keeps track of the number of periods
 
		for (int x =0; x < Username.length(); x++) {
		if ((Username.charAt(x) >= 48 && Username.charAt(x) <= 57) || (Username.charAt(x) >= 65 && Username.charAt(x) <= 90) 
				|| (Username.charAt(x) >= 97 && Username.charAt(x) <= 122) || (Username.charAt(x) == 64) ||
				(Username.charAt(x) == 46) || (Username.charAt(x) == 95)) { //Keep the Username } else { result = "Username Contains Invalid Character!"; //Checks that password contains only letters and numbers } if (Username.charAt(x) == 64) { //Finds the location of the (@) symbol atLoc = x; //and counts the number of (@) symbols in username atCount++;
		} if (Username.charAt(x) == 46) { 
			result = "valid";//Finds the location of the period perLoc = x; //and counts the number of periods in username perCount++;
		}
		} // Ends the for loop
 
		if ((atLoc < 1) || (perLoc < 1) || (perLoc == Username.length()-1)) { //Checks that email contains a period and an (@) symbol and
		result = "Not a valid email address"; //that they are not in the first or last position in the Username.
		}
 
		if (perLoc < atLoc) {
		result = "Not a valid email address"; //Checks that the (@) symbol follows the period in the username
		}
 
		if ((atCount > 1) || (perCount > 1)) { //Checks that there is only one (@) symbol and one period in a username
		result = "Not a vaild email address";
		}
 
		if ((perLoc - atLoc) <= 1) {
		result = "Not a vaild email address";
 
		}
		return (result);// Returns the value of "result"
 
		} // Ends the UserCheck method
		}//Ends the ValidateUser Class

Still not sure what to do.

Sorry for incomplete explanation..
I think you almost got it..
but I think you can do this in simple way..
1 @ case
==
you need to make a boolean function that return true if the username(String) contain '@'
private boolean checkforcase1(){
for(int i=0;i<username.length;i++){
//check the '@' character
//if it's there simply return true
}
return false;
}

if true, then you need to check
2. .com, .org etc case
===
first you have to find index where '.' is located, make a int function to get the location of '.'
if you got the location
now you need to get the string('.com','.org' or etc) from username, you can use one of String method, substring(int begin, int end)
assume begin is the '.' location and end is the length of username.
if the string is got, now you can compare with your predefine string array['.com','.org', etc] that you accepted..
if there is you can say that's a valid else invalid
the main flow diagram is like this
1. if case 1 is true than execute case 2 else return false and enter the invalid email address
2. if case 2 is return true you can print valid else invalid

There is more you can do with String (method), I suggested you to "try and error" which one you like...