java.lang.NullPointerException during database conectivity in struts

Question

0.00/5 (No votes)

See more:

Hi, I am making database connectivity in struts and getting error:javax.servlet.ServletException: java.lang.NullPointerException, code:-
config.xml:

XML

<form-beans>
    <form-bean name="DemoTestForm" type="DemoTestForm"/>
</form-beans>
<action-mappings>
    <action input="/index.jsp" name="DemoTestForm" parameter="testMethod" path="/test" scope="request" type="DemoTestAction">
        <forward name="success" path="/welcomeStruts.jsp"/>
        <forward name="fail" path="/Failure.jsp"/>
    </action>
</action-mappings>

DBConnect.java:

Java

import java.sql.*;
public class DBConnect
{
    Connection con=null;
    String result;
    public String checkUser(String name,String pass)
            throws Exception
    {
        try
        {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            con = DriverManager.getConnection
                    ("jdbc:oracle:thin@localhost:1521:xe", "system", "java");
        }catch(ClassNotFoundException cnf)
        {
            cnf.getMessage();
        }
        finally
        {
            con.close();
        }
        return(result);
    }
}

DemoAction.java:

Java

public class DemoTestAction
        extends org.apache.struts.action.Action {
    @Override
    public ActionForward execute(ActionMapping mapping,
            ActionForm form,
            HttpServletRequest request,
            HttpServletResponse response)
            throws Exception {
        DemoTestForm f = (DemoTestForm)form;
        String name = f.getTextName();
        String pass = f.getTextPass();
        String logic=null;
        DBConnect db=new DBConnect();
        db.checkUser(name, pass);
        Statement stmt=null;
        ResultSet rs=null;
        stmt=db.con.createStatement();
        rs=stmt.executeQuery("select * from admin");
        while (rs.next())
        {
            pass.equals(rs.getString(3))))
            if (name.equals(rs.getString(2)) && pass.equals(rs.getString(3))) {
                logic="success";
                break;
            }
            else
            {
                logic="fail";
            }
        }
        return mapping.findForward(logic);
    }
}

index.jsp:

XML

<html:form action="/test">
 Name: <html:text property="textName"/><br>
 Password:   <html:password property="textPass"/><br>
 <html:submit property="loginButton" value="Login Here"/>
 </html:form
>

Please help solve my problem.

Posted 11-Nov-10 7:24am

amitpinku8309

Updated 11-Nov-10 21:44pm

Nagy Vilmos

v4

Add a Solution

Comments

Nagy Vilmos 11-Nov-10 16:59pm

added some formatting; needs more.

Nagy Vilmos 11-Nov-10 17:01pm

@amitpinku Try debugging it. Somewhere in this, you are accessing an object that has not been initilised, hence null pointer.

amitpinku8309 12-Nov-10 2:26am

i have already debug my program and i have initialized all object .....so plzz check my prog ...

Nagy Vilmos 12-Nov-10 3:27am

@amitpinku There is alot of information missing:
- Stack trace?
- If you have debugged, what line throws the exception?

Please add these to the question - click the green 'Improve question' text and maybe I, or someone, can see where the problem lies.

Finally, try spelling words in full and using capitalisation. There is nothing to get people more annoyed on cp then 'i', 'plzz' or 'gizus codz'.

Nagy Vilmos 12-Nov-10 3:44am

And I've formatted your code for you.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Nagy Vilmos · Answer 1 · 2010-11-11T21:51:00

Look at the following code:

C#

try {
    Class.forName("oracle.jdbc.driver.OracleDriver");
    con = DriverManager.getConnection
            ("jdbc:oracle:thin@localhost:1521:xe", "system", "java");
}
catch (ClassNotFoundException cnf) {
    cnf.getMessage();
}
finally
{
    con.close();
}
return(result);

Every time the code is executed the finally block is executed. It is there to clean up after a try block and is executed irrespective of if there has been an exception or not.

So after opening a DB connection you close it.

Also, even though it's not used, result is not being set.