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Servlet problems

Hello:

Im a new to working with servlets so please bear with me:

I have 2 classes, one that reads database connection details from a file and establishes a database connection with a mysql database. and a second class (a servlet) that for now just does a simple query on the database and returns the result.

2 problems with the servlet code (no problems with the other class):

1. from the init method of the servlet, i call a method in my EstablishDBConnetion class to establish the connection. The compiler says i cannot reference this no-static method from a static context(Must it be static for my to reference it by Class.method ?)

2. The compiler doesnt seem to recognize its a servlet.

errors:

CustomQuery.java:12: non-static method establishConnection() cannot be referenced from a static context

                EstablishDBConnetion.establishConnection();

                                    ^

CustomQuery.java:19: package response does not exist

                PrintWriter printer = new response.getWriter();

                                                  ^

CustomQuery.java:23: cannot find symbol

symbol  : variable establishConnection

location: class EstablishDBConnetion

                Statement stmt = EstablishDBConnetion.establishConnection.con.createStatement();

                                                     ^

CustomQuery.java:40: cannot find symbol

symbol  : variable con

location: class CustomQuery

                con.close();

                ^

4 errors

Servlet Code

import java.io.*;

import java.sql.*;

import java.util.*;

import javax.servlet.*;

import javax.servlet.http.*;



public class CustomQuery extends HttpServlet

{



        public void init() throws ServletException

        {

                EstablishDBConnetion.establishConnection();

                

        }



        public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException

        {

                response.setContentType("text/html");

                PrintWriter printer = new response.getWriter();



                String title = "Result from custom query";



                Statement stmt = EstablishDBConnetion.establishConnection.con.createStatement();



                ResultSet rs = stmt.executeQuery("select customerID from customer");



                

                

                while(rs.next())

                {

                        

                        printer.println("<html> <head><title>" + title + "</title><br><br><table border=\"0\"> <tr><td>" + rs.getString(1) +"</td></tr></table></body></html>");

                        

                

                                                

                }



                rs.close();

                stmt.close();

                con.close();

        }



}

Establish Connection Code

import java.io.*;

import java.sql.*;

import java.util.StringTokenizer;



class EstablishDBConnetion

{



   public void establishConnection()

        {

                           

                   try

                {

                        String dbDriver ="";

                        String dbUrl="";

                        String dbName="";

                        String dbUser="";

                        String dbPassword = "";

                        String newLine = "";



                        BufferedReader fileRead = new BufferedReader(new FileReader("connection.txt"));

                        boolean readerStatus = fileRead.ready();

                        

                        newLine = fileRead.readLine();



                        while (readerStatus)

                        {



                                StringTokenizer st = new StringTokenizer(newLine,",");



                                while (st.hasMoreTokens())

                                {

                                        dbDriver   = st.nextToken();

                                        dbUrl      = st.nextToken();

                                        dbName     = st.nextToken();

                                        dbUser     = st.nextToken();

                                        dbPassword = st.nextToken();

                                }

                                                                

                                readerStatus = fileRead.ready();



                        }



                        Class.forName(dbDriver);

                        String url = dbUrl + dbName;

                        Connection con = DriverManager.getConnection(url, dbUser, dbPassword);



                        

                }



                catch (IOException e)

                {

                        System.out.println("IO exception in establishConnection()");



                        e.printStackTrace();

                }



                catch (java.lang.Exception ex)

                {

                        System.out.println("General exception in establishConnection()");

                        ex.printStackTrace();

                }

  }



}

My Classpath:

.;C:\Program Files\QuickTime\QTSystem\QTJava.zip;"X:\Documents and Settings\Paul\My Documents\java\Code\servlets\invoice";"C:\Program Files\Apache Software Foundation\Tomcat 6.0\lib\servlet-api.jar"

Again, many thanks

pls ignore above code and errors, and see correct below

Errors

CustomQuery.java:4: package javax.servlet does not exist
import javax.servlet.*;
^
CustomQuery.java:5: package javax.servlet.http does not exist
import javax.servlet.http.*;
^
CustomQuery.java:7: cannot find symbol
symbol: class HttpServlet
public class CustomQuery extends HttpServlet
^
CustomQuery.java:10: cannot find symbol
symbol : class ServletException
location: class CustomQuery
public void init() throws ServletException
^
CustomQuery.java:16: cannot find symbol
symbol : class HttpServletRequest
location: class CustomQuery
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
^
CustomQuery.java:16: cannot find symbol
symbol : class HttpServletResponse
location: class CustomQuery
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
^
CustomQuery.java:16: cannot find symbol
symbol : class ServletException
location: class CustomQuery
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
^
CustomQuery.java:12: non-static method establishConnection() cannot be referenced from a static context
EstablishDBConnetion.establishConnection();
^
CustomQuery.java:19: package response does not exist
PrintWriter printer = new response.getWriter();
^
CustomQuery.java:23: cannot find symbol
symbol : variable establishConnection
location: class EstablishDBConnetion
Statement stmt = EstablishDBConnetion.establishConnection.con.createStatement();
^
CustomQuery.java:40: cannot find symbol
symbol : variable establishConnection
location: class EstablishDBConnetion
EstablishDBConnetion.establishConnection.con.close();
^
11 errors

Code

import java.io.*;

import java.sql.*;

import java.util.*;

import javax.servlet.*;

import javax.servlet.http.*;



public class CustomQuery extends HttpServlet

{



        public void init() throws ServletException

        {

                EstablishDBConnetion.establishConnection();

                

        }



        public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException

        {

                response.setContentType("text/html");

                PrintWriter printer = new response.getWriter();



                String title = "Result from custom query";



                Statement stmt = EstablishDBConnetion.establishConnection.con.createStatement();



                ResultSet rs = stmt.executeQuery("select customerID from customer");



                

                

                while(rs.next())

                {

                        

                        printer.println("<html> <head><title>" + title + "</title><br><br><table border=\"0\"> <tr><td>" + rs.getString(1));

                        

                

                                                

                }



                rs.close();

                stmt.close();

                EstablishDBConnetion.establishConnection.con.close();

        }



}

db Connection code

import java.io.*;

import java.sql.*;

import java.util.StringTokenizer;



class EstablishDBConnetion

{



   public void establishConnection()

        {

                           

                   try

                {

                        String dbDriver ="";

                        String dbUrl="";

                        String dbName="";

                        String dbUser="";

                        String dbPassword = "";

                        String newLine = "";



                        BufferedReader fileRead = new BufferedReader(new FileReader("connection.txt"));

                        boolean readerStatus = fileRead.ready();

                        

                        newLine = fileRead.readLine();



                        while (readerStatus)

                        {



                                StringTokenizer st = new StringTokenizer(newLine,",");



                                while (st.hasMoreTokens())

                                {

                                        dbDriver   = st.nextToken();

                                        dbUrl      = st.nextToken();

                                        dbName     = st.nextToken();

                                        dbUser     = st.nextToken();

                                        dbPassword = st.nextToken();

                                }

                                                                

                                readerStatus = fileRead.ready();



                        }



                        Class.forName(dbDriver);

                        String url = dbUrl + dbName;

                        Connection con = DriverManager.getConnection(url, dbUser, dbPassword);



                        

                }



                catch (IOException e)

                {

                        System.out.println("IO exception in establishConnection()");



                        e.printStackTrace();

                }



                catch (java.lang.Exception ex)

                {

                        System.out.println("General exception in establishConnection()");

                        ex.printStackTrace();

                }

  }



}

Quote:

Originally Posted by paulchwd (Post 124707)

CustomQuery.java:4: package javax.servlet does not exist
import javax.servlet.*;

Check your classpath. Also, what are you using to compile the code?

AS far as I understand the classpath should have :

., my development directory and the location of the servlet jar file.

X:\Documents and Settings\Paul\My Documents\java\Code\servlets\invoice" is the exact directory where my class and java files are.

To compile I am using the command line (javac command)

Any thoughts?

I ensured my Classpath is correct, and it still wont work, but if i use the -classpath option at the commandline when compiling it recognizes that i am importing the servlet packages, but i still get these errors:

CustomQuery.java:19: package response does not exist
PrintWriter printer = new response.getWriter();
^
CustomQuery.java:24: cannot find symbol
symbol : variable establishConnection
location: class EstablishDBConnetion
Statement stmt = EstablishDBConnetion.establishConnection.con.createStatement();
^
CustomQuery.java:39: cannot find symbol
symbol : variable establishConnection
location: class EstablishDBConnetion
EstablishDBConnetion.establishConnection.con.close();
^
3 errors

For starters, it doesn't understand what the response object is
and then it doesxnt like the way i call Statement stmt = EstablishDBConnetion.establishConnection.con.createStatement();,

(FYI: con is in the establishConnection method of the EstablishDBConnetion class)