Display excel file from jsp

Question

hi i am trying to read an excel file from a location on the app server and display it in the browser (ie). the excel file should open up and not display the open/save dialog.
following is the code that i am using. i am not able to get it to work. getting an illegalstateexception and also i am getting all garbage diplayed in the browser. no excel. kindly help.
<%@ page import="java.io.*" contentType="application/vnd.ms-excel"%>
<%@ taglib uri="/WEB-INF/tlds/sapphire.tld" prefix="sapphire" %>
<%@ taglib uri="/WEB-INF/tlds/c.tld" prefix="c" %>
<%
//response.reset();
//response.setHeader("Pragma", "no-cache");
//response.setHeader("Cache-Control", "no-cache");
//response.setDateHeader("Expires", 0L);
ServletOutputStream so = response.getOutputStream();
String filename = "C:\\example1.xls";
String mimetype = "application/vnd.ms-excel";
ByteArrayOutputStream output = new ByteArrayOutputStream();
InputStream in = new BufferedInputStream(new FileInputStream(filename));
byte bytebuff[] = new byte[500];
for(int lengthread = 0; (lengthread = in.read(bytebuff)) != -1;){
output.write(bytebuff, 0, lengthread);
byte data[] = output.toByteArray();
response.setContentType(mimetype);
so.write(data);
in.close();
so.close();
%>

Answer 1

A JSP calls getWriter() by default.
Every time you have a carriage return outside <% %> it gets written to the writer.
The Illegal state exception would be because you are getting the outputStream after the writer.
This is better done in a servlet, but can be done in a JSP, try it with code like this:
<%@ page import="java.io.*" contentType="application/vnd.ms-excel"
%><%@ taglib uri="/WEB-INF/tlds/sapphire.tld" prefix="sapphire"
%><%@ taglib uri="/WEB-INF/tlds/c.tld" prefix="c"
%><%
%> Note that there is no text at all outside of the <% %> (not even carriage returns)
Also, why are you writing to a ByteArrayOutputStream (ie into a memory byte array), and then writing the byte array to the servletoutputstream?
Just put a buffer around the servlet outputstream and write directly to that.
ServletOutputStream so = response.getOutputStream();
BufferedOutputStream output = new ByteArrayOutputStream(so);
...