Passing resultset from Servlet to JSP

[Rajkumar balakrishnan]

Hi friends,
I involved in a project and recently i get up from a big mess up in MySQL. After that,i do another mess up. There i need the resultset obtained in the servlet page(A bean file) to be passed to the Invoking Servlet file and then it can be accessed by JSP file. I tried so many ways i even use session to bind the resultset and pass it it JSP page it seems to be not a good one. Here i found the code and i need your help where i use it and how i access it in my JSP page..

public ArrayList resultSetToArrayList(ResultSet rs){
   ResultSetMetaData md = rs.getMetaData();
   int columns = md.getColumnCount();
   ArrayList results = new ArrayList();
 
   while (rs.next()){
      HashMap row = new HashMap();
      results.add(row);
      for(int i=1; i<=columns; i++){
         row.put(md.getColumnName(i),rs.getObject(i));
      }
   }
   return results;
}

Any help will be appreciated...

[David O'Meara]

Where is the problem? You have shown us the code for extracting the values from the ResultSet, but how is this causing an issue?

[Rajkumar balakrishnan]

public ArrayList arrSend(String select) throws SQLException,IOException
{ 
 
        java.util.ArrayList all = new java.util.ArrayList(); 
        java.util.ArrayList pat = new java.util.ArrayList(); 
 
        String query = "select * from tbl_rmadetails where " + select ; 
 
        try 
{
            st = con.createStatement(); 
            rs = st.executeQuery(query); 
            while (rs.next()) 
{ 
                pat.add(rs.getObject("date")); 
                pat.add(rs.getObject("serial_no")); 
                pat.add(rs.getObject("replaced_serial_no")); 
                pat.add(rs.getObject("customer_inv_no")); 
                pat.add(rs.getObject("fault_desc")); 
                pat.add(rs.getObject("vendor_name")); 
            } 
            int pCount = 0; 
            for (int i = 0; i < pat.size(); i += 6)
     pCount++; 
             
            int startPat = 0; 
            for (int j = 0; j < pCount; j++)
 { 
               ArrayList everyPat = new ArrayList (); 
               int patNo = j + 1; 
               for (int k = startPat; k < patNo * 6; k++)
   { 
                   everyPat.add(pat.get(k)); 
               } 
               startPat = patNo * 6; 
               all.add(everyPat); 
            } 
}
           catch(Exception e)   
   {
   System.out.println(e);
   }
 
       return all; 
   }

The code for store resultset in an ArrayList... Then the value is returned to a servlet file...

public void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException
    {
        RMAEntryModel mb = new RMAEntryModel();
java.util.ArrayList blah=new java.util.ArrayList();

String vend=request.getParameter("vend");

mb.setVendor(vend);
              
try
{
blah=mb.arrSend(vend);
}
catch(Exception e)
{
throw new ServletException(e.getMessage());
}
}

    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException
    {
       doPost(request,response);
    }

My question is how can i pass the resultset to my JSP page....

[Rajkumar balakrishnan]

This is the bean file to store the resultset in an ArrayList...

public ArrayList arrSend(String select) throws SQLException,IOException
{ 
 
        java.util.ArrayList all = new java.util.ArrayList(); 
        java.util.ArrayList pat = new java.util.ArrayList(); 
 
        String query = "select * from tbl_rmadetails where " + select ; 
 
        try 
{
            st = con.createStatement(); 
            rs = st.executeQuery(query); 
            while (rs.next()) 
{ 
                pat.add(rs.getObject("date")); 
                pat.add(rs.getObject("serial_no")); 
                pat.add(rs.getObject("replaced_serial_no")); 
                pat.add(rs.getObject("customer_inv_no")); 
                pat.add(rs.getObject("fault_desc")); 
                pat.add(rs.getObject("vendor_name")); 
            } 
            int pCount = 0; 
            for (int i = 0; i < pat.size(); i += 6)
     pCount++; 
             
            int startPat = 0; 
            for (int j = 0; j < pCount; j++)
 { 
               ArrayList everyPat = new ArrayList (); 
               int patNo = j + 1; 
               for (int k = startPat; k < patNo * 6; k++)
   { 
                   everyPat.add(pat.get(k)); 
               } 
               startPat = patNo * 6; 
               all.add(everyPat); 
            } 
}
           catch(Exception e)   
   {
   System.out.println(e);
   }
 
       return all; 
   }

Then the value is returned to a servlet file...
servletrs.java

public void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException
    {
        RMAEntryModel mb = new RMAEntryModel();
java.util.ArrayList blah=new java.util.ArrayList();

String vend=request.getParameter("vend");

mb.setVendor(vend);
              
try
{
blah=mb.arrSend(vend);
}
catch(Exception e)
{
throw new ServletException(e.getMessage());
}
}

    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException
    {
       doPost(request,response);
    }

My question is how can i pass the resultset to my JSP page....

[Rajkumar balakrishnan]

I paste my full code here for your verification

[David O'Meara]

blah=mb.arrSend(vend);

and then what?
To make the information available to the JSP I would expect to see something like this:

blah=mb.arrSend(vend);
req.setAttribute"blah", blah);

[Rajkumar balakrishnan]

Yes i pass the resultset to JSP by the setAttribute() method but it fails to pass to the report.jsp page. May be i had some doubts on it. Will you please tell me how can i get that in my JSP page?

[David O'Meara]

doGet()
{
    // load data
    // put data on request by name
    // include jsp
}
 
my.jsp
//read from request using the name

That's about it. The JSP gets called using the same Request object, the request contains the data, the JSP reads the data.

Where are you calling include or forward to the JSP? sendRedirect won't work, it causes a new request to be sent and hence loses the data you put on it.

[Jetendra Ivaturi]

Hi I have done this thing which you are expecting Mr.Raj.

As David suggested... there I have added my object to a session object.

session.setAttribute("",) And further retrieved that in my JSP for display purpose it worked for me.

What I did in a glimpse:

1. Fetching the data from DB.
2. Added those record to ArrayList();// Here create a JavaBean with you Table format and add the object of that class in the arraylist.

eg: table--> name, no
class User{
getName()...}
ArrayList al=new ArrayList(new User());
3. Added that arraylist to session.
4. retrieved that object in JSP.


This is how I followed.

[Rajkumar balakrishnan]

Would you please give me an example code 'cause i do accordingly to your instruction but i can't get it and i really messed things as a whole.

[Sravan Kumar]

1. You have given us 2 methods named resultSetToArrayList() and arrSend(), I can see you are calling the latter from doPost(), where are you calling the other one? Should it be used?

2. Are you sure the list "blah" you want, has the correct results in the format you need?

3. In general, you might have to do these in doPost(), so the data correctly gets transferred to the JSP.
3.a. After you properly populate "mb", the bean, in doPost() of the servlet, you have to set it as an attribute in the request object

  request.setAttribute("rmaEntry", mb);  

3.b. After this, you have forward the request to your JSP page.

RequestDispatcher rd = request.getRequestDispatcher("report.jsp");
rd.forward(request, response);

3.c. You can then access this bean in report.jsp as follows:

RMAEntryModel mb = (RMAEntryModel) request.getAttribute("rmaEntry");

Please note that the attribute will be available only if you forward/include using RequestDispatcher. If you use response.sendRedirect(), you would lose the request attributes.

[Schandha Ravi]

Hi RajKumar,

The suggestions which the people have given so far would work for you. Not sure why you could not get the results into your jsp, unless you are actually creating a new request object (Not the one having hte resultset). This can happen if you do a redirect I believe, instead of RequestDispatcher forward or include. Try to check if the request objects are same on jsp page and in servlet. If they are same, then the Resultset should be available, if not obviously Resultset would not be available.

[Rajkumar balakrishnan]

Really my problem is i don't know how to retrieve values in the JSP page from the request object and i am still looking for an solution on that. And thanks for your replies...

[Jetendra Ivaturi]

session.setAttribute("get",get");

ArrayList al=(ArrayList)session.getAttribute(get);

This is how we get the object and use accordingly.

Sorry Raj I lost the code now. But am sure this works.

Be patient is debugging the code.

Once again an overview...

Add it to a session object

session.setAttribute("get",get);

after forwarding I mean RequestDispathcer...

session attribute is always true by default in jsp.

so Use session.getAttribute(get);

and typecast the same to your own format and use it.

[Rajkumar balakrishnan]

I retrieve it by session.getAttribute("get") and how do i print my value in JSP file? Help me regards this.

[Jetendra Ivaturi]

Suppose that get object you have added is an arraylist.

Then

ArrayList al=(ArrayList)session.getArrtribute("get");

and Iterate the ArrayList now.

[Rajkumar balakrishnan]

I am using AJAX along with JSP to pass the value of combo box to servlet and to fetch the value from DB without refreshing the page but it fails to works and the ajaxFunction is not triggered when i select a value from combobox. Here is the AJAX code for that

function getXMLObject()  //XML OBJECT
{
   var xmlHttp = false;
   try {
     xmlHttp = new ActiveXObject("Msxml2.XMLHTTP")  // For Old Microsoft Browsers
   }
   catch (e) {
     try {
       xmlHttp = new ActiveXObject("Microsoft.XMLHTTP")// For Microsoft IE 6.0+
     }
     catch (e2) {
       xmlHttp = false   // No Browser accepts the XMLHTTP Object then false
     }
   }
   if (!xmlHttp && typeof XMLHttpRequest != 'undefined') {
     xmlHttp = new XMLHttpRequest();        //For Mozilla, Opera Browsers
   }
   return xmlHttp;  // Mandatory Statement returning the ajax object created
}
 
var xmlhttp = new getXMLObject();//xmlhttp holds the ajax object
 
function ajaxFunction() {
  if(xmlhttp) { 
  var txtname = document.form2.vendor.value;
    xmlhttp.open("POST","vendor-pass",true); //getname will be the servlet name
    xmlhttp.onreadystatechange  = handleServerResponse;
    xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    var param=txtname.value;
xmlhttp.send(param); //Posting txtname to Servlet
  }
}
 
function handleServerResponse() {
   if (xmlhttp.readyState == 4) {
     if(xmlhttp.status == 200) {
       document.form2.message.innerHTML=xmlhttp.responseText; //Update the HTML Form element 
     }
     else {
        alert("Error during AJAX call. Please try again");
     }
   }
}

Will someone please tell me this function is to just pass the value to servlet. How can i fetch my data from server to AJAX. I right now use session to put my values and get it through in my JSP page.But it shows null values in the session field.Please give me a solution