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Answer 1

+2 A:

        HSSFWorkbook book;
        HSSFSheet sheet;
        HSSFRow row;
        CreationHelper createHelper = book.getCreationHelper();

Your using the book object before initializing it.

amal 2010-08-18 11:01:24

I'm not getting any content in that excel file... Can you identify why?

venJava 2010-08-18 11:08:51

@ven coder, where is the code where you write the workbook to a file? You create the object and add data to it, but you never write it somewhere. From the POI Javadocs, looks like you need to call `book.write(OutputStream)`

matt b 2010-08-18 11:14:05

Answer 2

+1 A:

I'd recommend not doing it this way.

Scriptlet code in JSPs is simply wrong.

Putting database access in a page like this isn't good, either.

A better approach would be Spring MVC and its JExcelView.

duffymo 2010-08-18 11:05:53

Answer 3

+2 A:

The way you are trying to do it doesn't make any sense. You can't mix HTML with Excel like that. Better create a servlet instead of a JSP page and let this servlet output only the Excel file and nothing else.

Something like this:

import java.io.*;    
import javax.servlet.http.*;
import javax.servlet.*;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
// ... plus all the other libs you need

public class ExcelServlet extends HttpServlet {
  public void doGet (HttpServletRequest req,
                     HttpServletResponse res)
    throws ServletException, IOException
  {
    HSSFWorkbook book;
    // ...
    // fill the book
    // ...
    res.setContentType("application/vnd.ms-excel");
    book.write(res.getOutputStream());
    res.getOutputStream().close();
  }
}

ammoQ 2010-08-18 11:08:45

I've done as you've recommended. But I'm getting **Error : <br>java.lang.IllegalStateException: getWriter() has already been called for this response** as the excel content . Can you clarify, why?

venJava 2010-08-18 11:25:39

I've produced the code as you've recommended. check it out pls..

venJava 2010-08-18 11:31:54

You can not call both getWriter() and getOutputStream() on the same response object. I guess JSP pages implicitely call getWriter(), that's why you should make it a servlet. (But don't take my word for it, I'm not an JSP expert)

ammoQ 2010-08-18 13:11:42

Answer 4

A:

Here's a tip on how to debug JSP exceptions:

in the stacktrace, this class

java.lang.NullPointerException
org.apache.jsp.GetReport_jsp.<init>(GetReport_jsp.java:29)

is the generated java class for your GetReport.jsp. You can look in the $TOMCAT_HOME/work/<enginename>/<hostname>/<appname> folder to see the actual code generated, and see what exactly is at line 29.

matt b 2010-08-18 11:11:41

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Display Excel sheet in the Browser?

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