I'm trying to stream an XLS file from a servlet and I'm having some trouble. What's the problem?
</question>
<answer>
<p>
The problem usually manifests itself as the junk characters being shown on
screen. The problem persists even though you have set the correct mime type.
</p>
<p>
The short answer is, don't depend on IE to display a binary file type properly if you stream it via a
servlet. Every minor version of IE has different bugs on this issue.
</p>
<p>
The problem in most versions of IE is that it does not use the mime type on
the HTTP response to determine the file type; rather it uses the file extension
on the request. Thus you might want to add a
<strong>.xls</strong> to your request
string. For example
<em>http://yourserver.com/myServelet.xls?param1=xx</em>. This is
easily accomplished through URL mapping in any servlet container. Sometimes
a request like
<em>http://yourserver.com/myServelet?param1=xx&dummy=file.xls</em> is also
known to work.
</p>
<p>
To guarantee opening the file properly in Excel from IE, write out your file to a
temporary file under your web root from your servelet. Then send an http response
to the browser to do a client side redirection to your temp file. (Note that using a
server side redirect using RequestDispatcher will not be effective in this case)
</p>
<p>
Note also that when you request a document that is opened with an
external handler, IE sometimes makes two requests to the webserver. So if your
generating process is heavy, it makes sense to write out to a temporary file, so that multiple
requests happen for a static file.
</p>
<p>
None of this is particular to Excel. The same problem arises when you try to
generate any binary file dynamically to an IE client. For example, if you generate
pdf files using
<linkhref="http://xml.apache.org/fop">FOP</link>, you will come across many of the same issues.
</p>
<!-- Thanks to Avik for the answer -->
</answer>
</faq>
<faq>
<question>
I want to set a cell format (Data format of a cell) of a excel sheet as ###,###,###.#### or ###,###,###.0000. Is it possible using POI ?
</question>
<answer>
<p>
Yes. You first need to get a HSSFDataFormat object from the workbook and call getFormat with the desired format. Some examples are <linkhref="hssf/quick-guide.html#DataFormats">here</link>.
</p>
</answer>
</faq>
<faq>
<question>
I want to set a cell format (Data format of a cell) of a excel sheet as text. Is it possible using POI ?
</question>
<answer>
<p>
Yes. This is a built-in format for excel that you can get from HSSFDataFormat object using the format string "@". Also, the string "text" will alias this format.
</p>
</answer>
</faq>
<faq>
<question>
How do I add a border around a merged cell?
</question>
<answer>
<p>Add blank cells around where the cells normally would have been and set the borders individually for each cell.
We will probably enhance HSSF in the future to make this process easier.</p>
</answer>
</faq>
<faq>
<question>
I tried to set cell values and Excel sheet name on my native language,
but I failed to do it. :(
</question>
<answer>
<p>By default HSSF uses cell values and sheet names as compressed unicode,
so to support localization you should use Unicode.
