Java

Username ,Password Validation

25-Jul-13 7:05

This question is far too broad for a technical forum such as this. You need to do your own research and study before deciding which technologies will be best to address your problem.

Use the best guess

chdboy23-Jul-13 22:16

23-Jul-13 22:16

I want to validate Username and Password matching from my sql Database,but it didn't work.Even if the text fields are blank it does not give any error.

Java

private static void selectfromdb() throws SQLException
	{	
	    Statement stmt = Connectionstring().createStatement();
		ResultSet rs = stmt.executeQuery("SELECT Username,Password FROM LoginDetails where Username='"+tf_Fname+"' AND Password ='"+tf_Lname+"'");
		while (rs.next())
		{  
            String x = tf_Fname.getText();              
            String pass = new String(tf_Lname.getPassword());
            if (x.equals(rs.getString("Username"))) 
            {  
                if (pass.equals(rs.getString("Password")))
                {  
                	JOptionPane.showMessageDialog(null,"Login Successful! ","Success",JOptionPane.WARNING_MESSAGE);
                    //System.out.println("Logged in!");  
                }
                else
                {  
                	JOptionPane.showMessageDialog(null,"Login UNSuccessful! ","UNSuccessful",JOptionPane.WARNING_MESSAGE);
                   // System.out.println("Password did not match username!");  
                }  
            }  
        }             
				
		}

Blue_Boy23-Jul-13 22:58

Blue_Boy

23-Jul-13 22:58

Try this

Java

private static void selectfromdb() throws SQLException
	{	
	    Statement stmt = Connectionstring().createStatement();
		ResultSet rs = stmt.executeQuery("SELECT Username,Password FROM LoginDetails where Username='"+tf_Fname+"' AND Password ='"+tf_Lname+"'");
		

	 rs.last();
    int rowcount = rs.getRow();
	if(rowcount ==0){
	JOptionPane.showMessageDialog(null,"Login UNSuccessful! ","UNSuccessful",JOptionPane.WARNING_MESSAGE);
	}
	else{
		JOptionPane.showMessageDialog(null,"Login Successful! ","Success",JOptionPane.WARNING_MESSAGE);
	}
				
}

I Love T-SQL
"VB.NET is developed with C#.NET"
If my post helps you kindly save my time by voting my post.

Richard MacCutchan24-Jul-13 0:33

24-Jul-13 0:33

Blue_Boy wrote:

ResultSet rs = stmt.executeQuery("SELECT Username,Password FROM LoginDetails where Username='"+tf_Fname+"' AND Password ='"+tf_Lname+"'");

It is really bad form to give sample code that can lead to SQL injection[^].

Use the best guess

Blue_Boy24-Jul-13 1:31

Blue_Boy

24-Jul-13 1:31

I didn't gave example to use query which is able to inject, the user used by him/herself, i just gave solution how to manage login case.

I Love T-SQL
"VB.NET is developed with C#.NET"
If my post helps you kindly save my time by voting my post.

chdboy24-Jul-13 3:08

24-Jul-13 3:08

In both the cases even if it's right password it shows "Login UNSuccessful"

Richard MacCutchan24-Jul-13 5:03

24-Jul-13 5:03

Use your debugger to step through the code and see what values your variables contain at each stage.

Use the best guess

chdboy24-Jul-13 22:02

24-Jul-13 22:02

The row count is 0 when I debug it....but I'm using the same username and password what's in the database,why is it not accepting it?

Richard MacCutchan24-Jul-13 22:20

24-Jul-13 22:20

chdboy wrote:
The row count is 0 when I debug it....but I'm using the same username and password what's in the database,why is it not accepting it?

I have no idea since I have no access to your system. You need to investigate further to discover what is happening.

Use the best guess

chdboy25-Jul-13 4:04

25-Jul-13 4:04

Now I have changed the code

Java

PreparedStatement preparedStatement = Connectionstring().prepareStatement(
			    "Select Username from dbo.LoginDetails where Username = ? and Password =?");
	  String User = tf_Fname.getText();
	  String _Pass = new String(tf_Lname.getPassword());
			preparedStatement.setString(1, User);
			preparedStatement.setString(2, _Pass);
			ResultSet resultSet = preparedStatement.executeQuery();
			while (resultSet.next()) 
			{
			    System.out.println("Username is "+ resultSet.getString(1)+"Password is "+resultSet.getString(2));  
			}

But now it's picking up the right Username from the table ,if I don't use

Java

+"Password is "+resultSet.getString(2)

in the Print line,and if I use that I get an error

Java

com.microsoft.sqlserver.jdbc.SQLServerException: The index 2 is out of range.

Richard MacCutchan25-Jul-13 4:47

25-Jul-13 4:47

I guess that you need to look more closely at the contents of your ResultSet and its individual property items. Check with your debugger and also the documentation for the classes that you are working with.

Use the best guess

chdboy25-Jul-13 5:01

25-Jul-13 5:01

I think I got what is wrong with it.....I'm missing Select Username,Password ...hehe thanks

jschell24-Jul-13 9:48

jschell

24-Jul-13 9:48

So the code is telling you the values are not equal.

Figure out what the values are and you will see the difference. Either a debugger or a print them out.

But as a guess there is a case difference. The query doesn't care but the comparison does.

chdboy24-Jul-13 22:28

24-Jul-13 22:28

Java

com.microsoft.sqlserver.jdbc.SQLServerException: The result set has no current row.

But when I see it in the Database there are plenty of rows.
I don't understand why it is not picking up the rows ?

Object mutability

Neo1010121-Jul-13 3:03

Neo10101

21-Jul-13 3:03

How would one mutate an object that is final? By referencing the object and then doing a mutate() operation on it? e.g.:

Java

final Object o = new Object(); 
o.mutate();

I don't understand. If it was declared final, then how come you are allowed to mutate it (or is that not true)?

How would one make the Object immutable then? Meaning: not mutable in any way, not even by reference.
How do I make sure a reference cannot modify the object it refers to? So that MyObject o = new Object(); o.modify(); is not possible?

I also read on Wikipedia the following example:

Java

final Position pos = new Position(); //pos is immutable

members:
pos.x, pos.y, pos.z are mutable still, unless they are declared final.

So if I am understanding this correctly, in order to make an object/class completely immutable, everything in it including its reference has to be declared final? e.g.:

Java

final Position pos = new Position(); 

class Position { 
final int x; 
final int y; 
final int z;

public Position(){ 
x=1; 
y=2; 
z=3; 
} 

final void doA(){} 
final void doB(){} 
}

Re: Object mutability

Richard MacCutchan21-Jul-13 20:33

21-Jul-13 20:33

See Java theory and practice: To mutate or not to mutate?[^].

Use the best guess

Re: Object mutability

Neo1010122-Jul-13 0:32

Neo10101

22-Jul-13 0:32

Referring to that article, Listing 1: Q.: "Because Date is mutable, the scheduleTask method must be careful to defensively copy the date parameter (perhaps through clone()) into its internal data structure. Otherwise, task1 and task2 might both execute tomorrow, which is not what was desired. Worse, the internal data structure used by the task scheduler could become corrupt."

A few questions on this:
1) What is 'copying defensively'?
2) What do they mean by 'internal data structure'?
3) How could task1 and task2 execute tomorrow if the code is to be executed today? Then how can new Date() be tomorrow? I don't understand.
4) How would the internal data structure become 'corrupt'? What is 'corrupt' in this context? Containing inconsistent values?

Re: Object mutability

Richard MacCutchan22-Jul-13 1:44

complete spring example to get datasource from websphere

22-Jul-13 1:44

These questions should be addressed to the writer of that white paper.

Use the best guess

swarjava20-Jul-13 7:03

swarjava

20-Jul-13 7:03

Hi,
Iam looking for complete example using Spring to get connection pool object(datasource) which is created in websphere server.
I have tried in many ways but no luck facing with different kind of errors.
Thanks in advance for your time.

Problem Array and looping Ip address,How?

tolulan18-Jul-13 23:37

tolulan

18-Jul-13 23:37

Greetings all.
I have a program calculation ip address like this.

Java

public static void main(String[]args){
        int host=450;
        String sMask="255.255.254.0";
        String[] octet;
        String IpAddress="192.168.100.0";
        octet = IpAddress.split("\\.");
        int oct1=Integer.parseInt(octet[0]);
        int oct2=Integer.parseInt(octet[1]);
        int oct3=Integer.parseInt(octet[2]);
        int oct4=Integer.parseInt(octet[3]);
        int i;
        System.out.println("Ip Address \t \tSubnet Mask");
        for(i=oct4;i<host;i++){
            System.out.println(oct1+"."+oct2+"."+oct3+"."+i+"\t \t"+sMask);
        }
    }

print out from this program

Ip Address Subnet Mask
192.168.100.0 255.255.254
192.168.100.1 255.255.254
192.168.100.2 255.255.254
192.168.100.3 255.255.254
until...
192.168.100.449 255.255.254
Laugh | :laugh:

I want this program,if ip address octet 4 value "192.168.100.255",then continuing this program,like this.

next >
192.168.101.0 255.255.254
192.168.101.1 255.255.254
192.168.101.2 255.255.254
until ...
192.168.101.193 and Finish.

What the lack from my program?

Richard MacCutchan18-Jul-13 23:57

18-Jul-13 23:57

You need to add some extra code to cater for when i gets above 255. Something like:

for(i=oct4;i<host;i++){
    int value = i / 256;
    int rem = i % 256;
    oct3 += value;
    System.out.println(oct1 + "." + oct2 + "." + oct3 + "." + rem + "\t \t" + sMask);
}

Use the best guess

terry.schoof25-Jul-13 10:31

terry.schoof

25-Jul-13 10:31

The code above increments both oct3 and oct4 at the same time, one ahead the other, respectively.

Change:

Java

oct3 += value;

to:

Java

oct3 = value;

for:

Java

for(i=oct4;i<host;i++){
            int value = i / 256;
            int rem = i % 256;
            oct3 = value;
            System.out.println(oct1 + "." + oct2 + "." + oct3 + "." + rem + "\t \t" + sMask);
        }

Richard MacCutchan25-Jul-13 21:06

25-Jul-13 21:06

Actually we were both wrong; it should be:

Java

value += oct3;
System.out.println(oct1 + "." + oct2 + "." + value + "." + rem + "\t \t" + sMask);

Use the best guess