Doubt on Servlet having database connection?

[dhwani mathur]

Hi all!!

I have been trying to create a servlet
having a method which creates database
connection and inserts values using SQL statement

My servlet has three methods
doGet();
doPost();
disp();//This method consist of database connection
In the doGet() method i am calling disp();

i tried using the same method disp() in my
simple java program (ex abc.java )it works fine i mean
that it creates connection to the database
as well inserts value in the database table
also.

but when i put the same method disp()
in my Servlet and called it in doGet()
method it does not produce any output
not even a error or exception so i am
totally lost onto what i must do know


past two days i am on the same program
whats the reason that it works fine
in a normal java program but not in my servlet.
Please anyone can help me
on above it will be realy realy great.......


Thanks in advance





Dhawni:>Its always too soon to quit.

[Raghavan Muthu]

Hi dhwani,

As per your explanation, the code working fine in a normal java program should definitely work well with Servlet as well, since Servlet is also java class.

Can you please paste your java code here? so that it will help to get a solutions quickly!

[dhwani mathur]

hiiii Raghavan...............


this is code for my Servlet

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;
                                                                                                                                                             
public class test extends HttpServlet{
    String name, emailadd, passw;
                                                                                                                                                             
    public void doGet(HttpServletRequest request,HttpServletResponse response)
                 throws IOException,ServletException
    {
        response.setContentType("text/html");
        String name=request.getParameter("name");
        String email=request.getParameter("email");
        String pass=request.getParameter("pass");
                                                                                                                                                             
        //if condition is true only for one user ie dhwani ans passsword dream and
        PrintWriter pw=response.getWriter();
        //if condition is true bcoz i enter it in my html
        if(name.equals("dhwani")&&pass.equals("dream"))
        {
            try
            {
                //called method disp();
                disp(name,email,pass);
                [B]//this statements get printed[/B]
                pw.println("Welcome to home page"); 
            }
            catch(SQLException e)
            {
                e.printStackTrace();
            }
            catch(ClassNotFoundException ex)
            {
                ex.printStackTrace();
            }
            //another servlet called here once condition is true
            response.sendRedirect("ValidUser");
        }
        else
        {
            pw.println("You are not a Valid User");
        }
                                                                                                                                                             
    }
                                                                                                                                                             
    public void doPost(HttpServletRequest request,HttpServletResponse response)
            throws IOException,ServletException
    {
        doGet(request, response);
    }
                                                                                                                                                             
    public void disp(String Firstname,String Emailid,String Pass)
            throws SQLException,ClassNotFoundException
    {
        name = Firstname;
        emailadd = Emailid;
        passw = Pass;
        String sql = "insert into userinfo(name,email,password)values('"
                   + name
                   + "','"
                   + emailadd
                   + " ',' "
                   + passw+"')";
 
        System.out.println("just try");
        try
        {
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
            Connection con=DriverManager.getConnection("jdbc   :-o	    dbc:information");
            Statement stmt=con.createStatement();
            ResultSet rs=stmt.executeQuery(sql);
        }
        catch(SQLException e)
        {
            e.printStackTrace();
        }
    }
}

here is my method disp() when i call it in normal java class like abc.java its called
and data gets entered in table userinfo


but the same method when i am calling in doGet() method of my Servlet its not working...............

i hope if can anyone help me to where i am going wrong
it will be realy great.................

thanks in advance

Dhwani:>its always too soon to quit.


[BPSouther: Narrowed the code a bit to make the whole thread easier to read]
[ January 13, 2008: Message edited by: Ben Souther ]

[Raghavan Muthu]

Hi dhwani,

Though you have pasted your code using CodeTags, it would have been better if you took some time to just align/intend it

Well, it works fine for me. As i already told, a Servlet is also a java program only and no different from it, except the way it is treated and maintained.

After calling the disp() method, you are redirecting your request to another servlet named "ValidUser" . What exactly are you doing in the doGet() or doPost() method of it?

Ideally speaking, you should NOT see the output "welcome to home page" as you are redirecting the output.

As an effect of redirection, the request is considered as if a new request from the client and it is sent to the server.

Can you check the Server log? As you used SOPs inside disp() method for just try and its NOT with the response's output stream, you may NOT see it in your browser.

I don't see anything to stop the processing of your disp() method and redirection.

Just try and let us know with the requested details.

[dhwani mathur]

hi Raghavan

Thanks for your response

first of all i apologise for code identation mistake

secondly one more mistake is i forgot to comment that statement
in the code which i pasted above

response.redirect("ValidUser");

actualy in my original code i am NOT redirecting it
another servlet...the coding is just till
SOP statement ("Welcome to home page");

hence i mentioned that i am getting in output
"welcome to home page" but in my table there is no data
getting inserted

You said me to check for Server logs i
am a beginner in JSP and Servlets so
i dont have that mush idea onto what i must
check in my Server logs
Although there is a foler in Tomcat 6.x named logs
but it has text docs what i must check than in them?

do you think there can be any other problem in my code
that is not allowing my data to enter in table.........
i am totally lost with program..........



Any one more doubt onto which book i must refer
to learn JSP and Servlets so as to get
more knowledge

Anyways thanks in advance


Dhwani:>Its always to soon quit.

[Ben Souther]

Originally posted by dhwani mathur:
...
first of all i apologise for code identation mistake

secondly one more mistake is i forgot to comment that statement
in the code which i pasted above

You can always go back and edit an existing post by clicking on the
icon in that post.
I narrowed the code a bit for you but if there are other errors in there, it
would be a better idea to edit the post and fix them than to mention the errata later as many people won't see you later posts until after they're read your code.

-Ben

[Raghavan Muthu]

Originally posted by dhwani mathur:

first of all i apologise for code identation mistake

That's okay. You will get used to it. But please ensure you follow the same hereafter.

But as Ben told, you have an option of editing your own post very well. Please keep that in mind for future posts.

actualy in my original code i am NOT redirecting it
another servlet...the coding is just till
SOP statement ("Welcome to home page");

In that case, your servlet is working without any issues!

That's the only one output you provide. What else you want to prove further?

but in my table there is no data
getting inserted

This is a different issue. You better try to segregate and locate the error as it really helps all to concentrate!

You said me to check for Server logs i
am a beginner in JSP and Servlets so
i dont have that mush idea onto what i must
check in my Server logs

Yes, Tomcat being an application which provides you the runtime environment for running your JSPs and Servlets has its own location to store on what is happening with the applciations it hosts. The way it maintains is through logs.

Although there is a foler in Tomcat 6.x named logs
but it has text docs what i must check than in them?

Yes, you can find out some .log files inside the logs folder. As its been sometime i worked in Tomcat, i don't exactly remember the logfile name.

I guess you see can a file named "localhost.<yyyy-mm-dd>.log". Check in that file whether have you got any errors.

Any one more doubt onto which book i must refer
to learn JSP and Servlets so as to get
more knowledge

You can read Marty Hall's Core Servlets and JSPs book which is available for FREE here

You can also read the famous HFSJ (Head First Servlets & JSP) book by Kathy Seirra, Bert Bates ,Bryan Basham.

[Rahul Shilpakar]

does your records inserting in database table?

[Raghavan Muthu]

Originally posted by Rahul Shilpakar:
does your records inserting in database table?

Hi Rahul,

He says, it [b]is not[/i]. That's where he seems to face a problem!

[Raghavan Muthu]

Originally posted by Rahul Shilpakar:
does your records inserting in database table?

Hi Rahul,

He says, it is not. That's where he seems to face a problem!
[ January 14, 2008: Message edited by: Raghavan Muthu ]

[dhwani mathur]

hi Raghavan


first of all let me be very clear i am She not he
first time ever someone said me he

anyways rahul yes my data is not getting inserted in my table
that is where the problem is

hey raghavan yesterday i checked my server logs it shows
as below

   java.sql.SQLException: [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified
at sun.jdbc.odbc.JdbcOdbc.createSQLException(Unknown Source)
at sun.jdbc.odbc.JdbcOdbc.standardError(Unknown Source)
at sun.jdbc.odbc.JdbcOdbc.SQLDriverConnect(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcConnection.initialize(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at test.disp(test.java:66)
at test.doGet(test.java:28)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source) 

although i have created DSN to refer to my database than also
i am getting exception as Unknown dataSource
and have specified driver as well
i wont give up
i will try more on this program



anyways thanks a lot
for all the help till now.

Dhwani:>Its always too soon to quit.

[Raghavan Muthu]

Originally posted by dhwani mathur:


first of all let me be very clear i am She not he
first time ever someone said me he

Hello dhwani,

ouch... Sorry for my ignorance! but your name sounded like you are a he .

Perhaps i think we can suggest JavaRanch to have an icon to indicate the gender besides the name Wassay?

hey raghavan yesterday i checked my server logs it shows
as below

   java.sql.SQLException: [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified
at sun.jdbc.odbc.JdbcOdbc.createSQLException(Unknown Source)
at sun.jdbc.odbc.JdbcOdbc.standardError(Unknown Source)
at sun.jdbc.odbc.JdbcOdbc.SQLDriverConnect(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcConnection.initialize(Unknown Source)
at sun.jdbc.odbc.JdbcOdbcDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at test.disp(test.java:66)
at test.doGet(test.java:28)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
 

Yes, that's where we have a catch! It looks like the webserver (tomcat here) is not aware of the datasource being used and thats why it is unable to obtain a connection! That's why you have not got any output at all.

I have NOT worked with Type1 JDBC-ODBC driver. I have used Type2 and 4 drivers and there we need to provide the .jar file for the JDBC Driver in the lib directory of either your web application or the container's location.

Let me check with Type1 and get back. Meanwhile other ranchers with experience could help here i guess for Type1 Driver!

Meanwhile, where have you kept the JDBC driver jar file in your application?

i wont give up
i will try more on this program

That sounds really great! Keep it up!

Good luck!
[ January 15, 2008: Message edited by: Raghavan Muthu ]

[dhwani mathur]

Hi thr

Thanks for the reply once again
you said for jdbc.jar file
i searched it in my pc
but i am not getting
it......is the name jdbc.jar?only............

Dhwani:>Swimmers never weep.

[Raghavan Muthu]

Ouch.. it is not jdbc.jar!

its the .jar file for your jdbc driver!

what database you use?

[Baseet Ahmed]

Try to make proper datasource.
If you are using oracle,do pass the two additional parameters(username and password) in getConnection method.
And use proper url:jdbc dbc snname,userid,password

I think there is no need of additional jar file.
As Type 1 driver is already available in JDK.


Regards
Baseet Ahmed

"God has made every living thing from water."

[dhwani mathur]

hi thr!!!

i am using MySQL as database
and and i am checking for .jar file as
well hope i could find whats actualy missing.....

i have already checked for proper DSN
as well..... it is correct....
and i am using windows authentication
so no need of username and password.

i wil get back as i find correct .jar file to
be included...........for my type 1 driver

Dhwani:>It alaways too soon to quit.

[kalyan godavarthy]

Hello Lady
Appears like got stuck in the first step of creating a connection, you said it worked fine when you were executing through simple class and not working through a servlet, you sure it is getting inserted in the database, and the mysql*.jar in the tocat version/webapps/your application folder/web-inf/lib folder or the tomcat version/common/lib/ folder both of the tomcat installation directory you should place the jar file.
if you use a mysql database you might need to use the jdbc dbc://ip ort/database name along with the user name and password for the connection to be created.
if any doubts check for mysql url sample on google
thanks

[kalyan godavarthy]

Hello Lady
Appears like got stuck in the first step of creating a connection, you said it worked fine when you were executing through simple class and not working through a servlet, you sure it is getting inserted in the database, and the mysql*.jar in the tocat version/webapps/your application folder/web-inf/lib folder or the tomcat version/common/lib/ folder both of the tomcat installation directory you should place the jar file.
if you use a mysql database you might need to use the jdbc:odbc://ip:port/database name along with the user name and password for the connection to be created.
if any doubts check for mysql url sample on google
thanks

[Aneel Ansari]

Hi Dhwani mathur

The tip I am gonna give to you is not really related to your question, but still a good tip.
Please remember whenever you try to use UPDATE or INSERT statement the execution of the query should be like this "stmt.executeUpdate(sql);". what i saw in your code was, "stmt.executeQuery(sql);" which is bad practice, because you will never know what happened after the execution of your query.

best of luck

Aneel Ansari
[ January 16, 2008: Message edited by: Aneel Ansari ]

[dhwani mathur]

hello...........

as Kalyan Anand said i must put mysql.jar file
in Tomcat/lib/ but mysql.jar is to be put when
i am using third party driver here i am using
jdbc type 1 driver sun.jdbc.odbc.JdbcOdbcdriver
so i think there should be no need of
mysql.jar .......but i am not sure onto if i am right
or not even i tried to download it but could nt ?
secondly thanks for the advice aneel ansaree
i will try to use the right query next time onwards.....

but my problem is at the same place still i have
not arrived to a solution onto it.............
but sure will get solution may be it takes time....

one thing i checked is when i created
my DSN i used windows authentication
and not SQl Server authentication
ie no username and password so can this
create any problem in my code?

[Ben Souther]

The driver sun.jdbc.odbc.JdbcOdbcdriver won't work for MySql.
It is for connecting to Microsoft databases via ODBC.

You will need to have the correct driver for the RDMS that you're using.

[Raghavan Muthu]

That's very true. You have to go with Type4 Driver for mysql. Please try with that.

Please read about the MySQL Connector J and its description here.

[Elanges waran]

Dear dhwani,

My suggestions for your problem as follows,

1. copy mysql.jar file on ..\Tomcat_home\..\lib folder

2. Changes your deriver and approach as follow :

Class.forName ("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection
( url, "your_mysgl_login", "your_mysgl_password" );
Statement stmt = con.createStatement ();
ResultSet rs = stmt.executeQuery (query);

I think above idea will help to you...

[Raghavan Muthu]

Originally posted by dhwani mathur:
hello...........

as Kalyan Anand said i must put mysql.jar file

The same i have told earlier. I guess you have missed it !

...and not SQl Server authentication

Are you using MySQL or SQL Server?

Please be patient when reading the replies as well acknowledging. It would save and avoid further confusions

[dhwani mathur]

hi all...!!!

Ooopss sorry sorry i mistakened again
i am using SQL server and not MySql
so i think the driver i am using is correct.

hey raghavan

Please read about the MySQL Connector J and its description here.

i have seen this page but still not clear with the idea
of using MySql Connector J.

and Elanges waran i tried to download mysql.jar
i got mysql.zip i unzipped it
but i couldnt figure out actualy it has three folders
com,org Meta-INF
which one i must link to my project?

please specify that

and then i will change the driver as well
you have mentioned to use
Class.forName ("com.mysql.jdbc.Driver");


lets see i could get the output as expectated.

Thanks to all for all the help till now.

Dhwani:>its always too soon to quit.

[Raghavan Muthu]

Originally posted by dhwani mathur:

Ooopss sorry sorry i mistakened again
i am using SQL server and not MySql
so i think the driver i am using is correct.

and Elanges waran i tried to download mysql.jar
i got mysql.zip i unzipped it
but i couldnt figure out actualy it has three folders
com,org Meta-INF
which one i must link to my project?

please specify that

and then i will change the driver as well
you have mentioned to use
Class.forName ("com.mysql.jdbc.Driver");

Hello Dhwani,

Please hold on for a moment. Be patient first. Be Clear on what you do.

See the above two sections. First you told, you are using SQL Server and in the next, you say you try to make use of mysql's jar file! How it will be comptaible?

Just think over. You are not supposed to use MySQL's jdbc driver when you use SQLServer. They both are of totally different vendors. You should look for SQL Server's JDBC driver now. Are you clear now?

Try your luck now with SQL Server's JDBC Driver! Good luck

[dhwani mathur]

Heloooo Raghavan!!

i am again in wrong direction sorry...



i realy need to have some patience
while i work i dont know how
i mixed up with two different concepts
of SQL Server and MySql.

yes i must try on SQL Servers JDBC driver

now i am clear with what i must use and what not......
and will come back as i get some solution on it.

it feels like



but still dont want to give up with this program.


Dhwani:>Its always too soon to quit.

[Raghavan Muthu]

That is okay and alright dhwani.

I guess you need a *break*. Just take a break and start afresh with the clear mindset without confusing yourself much!

[Baseet Ahmed]

[Hi-jack removed]

Baseet Ahmed,
Please start your own thread if you have a similar question.
Adding your issue to someone else's thread is called hi-jacking and is considered rude.
[ January 18, 2008: Message edited by: Ben Souther ]

[Baseet Ahmed]

Ok.
If it is called hi-jacking,
then it has to be banned for all users and in all cases.

Will post a fresh thread on the same topic.


Thank you.

Regards
Baseet Ahmed.

"God has made every living thing from water."

[Ankur Sharma]

Hi Dhwani,

I see the last post was on Jan 17th, I assume your problem is solved.
If you are still having a problem you can use JTDS driver to connect to SQLServer.

Thanks,

Ankur

[dhwani mathur]

hi ankur

my problem is not yet solved
i was just studying so that may be i could find some solution to it.
Recently while studying i came to know about
<Realm > in the server.xml file but
still i am not clear with it......
you have suggested on JTDS can you
ellaborate on it........

Dhwani:>Its always too soon to quit.

[Ben Souther]

Conversation has moved to:
http://www.javaranch.com

dhwani,
Please try to keep this issue in one thread.
If you start to think that it would do better in another forum, just ask a moderator to move it for you.

-Ben