initialcontext lookup retun null for datasource

[Edward Fernando]

right now im trying to connect to db from jsp, and i am using datasource...
first thing i make the Resource in context.xml like this

<?xml version="1.0" encoding="UTF-8"?>
<Context antiJARLocking="true" path="/WINDO">
    
    <Resource name="jdbc/windoDB" 
              auth="Container"
              maxActive="100" 
              maxIdle="30" 
              maxWait="10000"
              username="XYZ" 
              password="XYZ"    
              driverClassName="com.mysql.jdbc.Driver"
              url="jdbc:mysql://127.0.0.1:3306/testDB" 
              logAbandoned="true" 
              removeAbandoned="true"
              removeAbandonedTimeout="60" 
              type="javax.sql.Datasource"
              factory = "org.apache.tomcat.jdbc.pool.DataSourceFactory" />

</Context>

then i make the jsp like this...just to test the connection....

InitialContext ic = new InitialContext();
            String msg;
            boolean lookupStat;
            try{
                ic.lookup("java:comp/env/jdbc/testDB");
                msg = "name found";
                lookupStat = true;
            }
            catch(Exception e){
                msg = e.toString();
                lookupStat = false;
            }

not getting any name exception then i'm assuming that binding is success....CMIIW

next i'm trying to make a Data source..with code like this....

if(lookupStat = true){
                DataSource ds = null;
                Connection conn;
                try{
                    ds = (DataSource)ic.lookup("java:comp/env/jdbc/testDB");
                }
                catch(Exception e){
                    msg = e.toString();
                }
                if(ds == null){
                    msg = msg+"ds null";
                }
                else{
                    msg = "ds not null";
                }

            }

and here comes the problem....i dont know what is wrong but the datasource alway null....where did it go wrong? please help me....

[Paul Clapham]

Did you mean for the JNDI string "java:comp/env/jdbc/testDB" to match the resource named "jdbc/windoDB"?

I don't see any other possibility, there's only one resource there. You might want to choose a better JNDI string.

[Paul Clapham]

And here's another thing:

if(lookupStat = true){

Here you have an assignment as your if-expression. That assignment always assigns "true" to the "lookupStat" variable. And then when it's used to control the if-clause, well, it's always true so the code in that block will always be executed. I assume your statement that you weren't getting a name exception is based on the if-clause being executed, rather than actually debugging the code to see whether any exception was thrown?

If you want to compare two values (and you do want that) then use the == operator. The = operator is used for assignments.

And if you want to test a boolean expression to see if it's true, don't use either of those operators. (If you do, it's easy to choose the wrong one accidentally and put a bug into your code.) Here's what your code should be:

if(lookupStat){

[Edward Fernando]

Paul Clapham wrote:Did you mean for the JNDI string "java:comp/env/jdbc/testDB" to match the resource named "jdbc/windoDB"?

I don't see any other possibility, there's only one resource there. You might want to choose a better JNDI string.

hmm ok CMIIW....if i not get any "javax.naming.NameNotFoundException"...then there is no problem from the lookup right ? again CMIIW....

[Edward Fernando]

now i recreate the context the web.xml and the jsp like this

context.xml

<?xml version="1.0" encoding="UTF-8"?>
<Context antiJARLocking="true" path="/WINDO">
    
    <Resource name="jdbc/testDB"
              auth="Container"
              type="javax.sql.Datasource"
              maxActive="100"
              maxIdle="30" 
              maxWait="10000"
              username="****" 
              password="****"    
              driverClassName="com.mysql.jdbc.Driver"
              url="jdbc:mysql://localhost:3306/****"/>

</Context>
</code>

web.xml
[code=java]
    <resource-ref>
        <description>windoDB</description>
        <res-ref-name>jdbc/testDB</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Container</res-auth>
    </resource-ref>

and jsp page

<%-- 
    Document   : connection pooling test
    Created on : Oct 23, 2012, 12:12:00 PM
    Author     : bigedo
--%>

<%@page import="javax.naming.InitialContext"%>
<%@page import="org.apache.tomcat.jni.Pool"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <%@page import="customer.*" %>
        <%@page import="java.sql.*" %>
        <%@page import="Connection.*" %>
        <%@page import="javax.naming.InitialContext" %>
        <%@page import="javax.sql.DataSource" %>
        <%
            InitialContext ic = new InitialContext();
            DataSource ds;
            String msg = "";
            boolean lookupStat;
            try{
                ds = (DataSource)ic.lookup("java:comp/env/jdbc/testDB");
            }
            catch(Exception e){
                msg = msg+e.toString();
            }           
        %>
        <h1><%= msg %></h1>
    </body>
</html>

javax.naming.NamingException: Cannot create resource instance........what is wrong now?.....