Passing Parameters

[Suneel Setlur]

When I pass Parameters from one servlet to another using something like response.sendRedirect("http://webserver:7001/......?var=value") I get only the var in the second servlet and not the value. Where am I going wrong? Can you please give me a sample code..
[ June 15, 2002: Message edited by: Suneel Setlur ]

[Roy Ben Ami]

if you use sendRedirect then the parameters are not passed in the request, since it makes a new request on the client's browser.
try using, the forward() method with the requestDispatcher to forward the request to the second servlet instead of sendRedirect.

[Bear Bibeault]

Suneel, what exactly do you mean when you say that you "get the var but not the value"?
What actions are you taking to get the value of "var" and what is being returned?
I'm not yet convinced that this is a forward vs. redirect problem.
bear

[Suneel Setlur]

Hi
Thanks for the replies.
Ben can you give me an example code where I can pass a key & value pair like i=10 to the next servlet?
Bear I hae no difficulties with redirecting. I was wanting to pass a couple of parameters to the next servlet where I indicated that the variable(var)and its value needed to go the next servlet.

[Bosun Bello]

Suneel, you can just add it as an attribute to the request and then forward it to your servlet.
requestReference.setAttribute("Name", value)
requestDispatcherReference.forward(requestReference, responseReference)

[Michael Mendelson]

Suneel, hopefully this will help...

  
        out.println("Parameter names in this request:");
        Enumeration e = request.getParameterNames();
        while (e.hasMoreElements()) {
            String key = (String)e.nextElement();
            String[] values = request.getParameterValues(key);
            out.print("   " + key + " = ");
            //this additional loop is needed in case you have more than one parameter with the same name.
            for(int i = 0; i < values.length; i++) {
                out.print(values[i] + " ");
            }
            out.println();
        }

[Suneel Setlur]

Thanks Bosun....But I guess you have a look at my code and tell me where I am going wrong...coz the Weblogic Server gives me a NullPointerException.

 
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.naming.*;
import java.util.*;
import java.io.*;
public class trials extends HttpServlet {
Connection conn=null;
Statement st=null;

public void init(ServletConfig sc){
try
{
super.init(sc);
Context ctx=null;
System.out.println(" Variables Initialized ");

Hashtable ht=new Hashtable();
ht.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
ht.put(Context.PROVIDER_URL,"http://localhost:7001");
System.out.println(" properties put in Hashtable ");
ctx=new InitialContext(ht);
javax.sql.DataSource ds=(javax.sql.DataSource)ctx.lookup("suneelss");
conn=ds.getConnection();
st=conn.createStatement();
}
catch (Exception e)
{
e.printStackTrace();
}
}
public void doGet(HttpServletRequest request,HttpServletResponse response) {
try
{
PrintWriter out=response.getWriter();
System.out.println("in service");
int i=10;
Integer num=new Integer(i);
RequestDispatcher dispatcher=getServletConfig().getServletContext().getRequestDispatcher("http://localhost:7001/trials/try2");
request.setAttribute("cust_id",num);
dispatcher.forward(request,response);

}
catch(Exception e)
{
e.printStackTrace();
}
}
}
 

And this is the error

  
activating app: _appsdir_trials_war
Activate application _appsdir_trials_war on myserver( Running )
Activate application _appsdir_trials_war on myserver( Completed )
 Variables Initialized
 properties put in Hashtable
in service
java.lang.NullPointerException
        at trials.doGet(trials.java:44)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run
(ServletStubImpl.java:945)
        at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:332)
        at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubIm
pl.java:242)
        at weblogic.servlet.internal.WebAppServletContext$ServletInvocationActio
n.run(WebAppServletContext.java:5363)
        at weblogic.security.service.SecurityServiceManager.runAs(SecurityServic
eManager.java:721)
        at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppSe
rvletContext.java:3043)
        at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestIm
pl.java:2466)
        at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:152)
        at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:133)

Thanks