Question

I’m new to java and I am making a login program (based on text file processing) as part of my Java assignment so far I have written this code but it only checks the first line in the text file. I have also tried to add a for loop but it didn’t work either.

Could you please help me fix this problem.

(username and password are separated by a tab character in the file that’s why I used this (user+”\t”+pass))
Already tried the web, I didn’t find any good tutorial.

    FileInputStream fstream = new FileInputStream("file.txt");
    DataInputStream in = new DataInputStream(fstream);
    BufferedReader br = new BufferedReader(new InputStreamReader(in));
    String strLine;
    while ((strLine = br.readLine()) != null)   {
        if ((user+"\t"+pass).equals(strLine)) {System.out.println ("Sucess");}
    }

the text file is so

 x  y
 x  z
 x  t

so when you enter x and y the program says Success but for x and z or t there is no result!

Answer 1

Here is the full class:

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

public class Delete {

/**
 * @param args
 * @throws IOException
 */
public static void main(String[] args) throws IOException {
    FileInputStream fstream = new FileInputStream("C:/file.txt");
    DataInputStream in = new DataInputStream(fstream);
    BufferedReader br = new BufferedReader(new InputStreamReader(in));
    String strLine;
    String user = "john";
    String pass = "doe";
    while ((strLine = br.readLine()) != null) {
        if ((user + "\t" + pass).equals(strLine)) {
            System.out.println("Sucess");
        }
    }

}

}

And the file.txt:

john    doe
john    doe
john    doe
mary    doe

As you would expect, the console output is:

Sucess
Sucess
Sucess

So the piece of code you posted does check all lines. Please paste the contents of your file and your user and password strings.