Excel file is corrupted when i download it

[mallikarjun dontamsetti]

hi, i have generated excel file using Apache POI .it is generated in my root path under excel folder.when user click save as excel the created file should download to user chosen location. it is get downloaded to that perticular path given by user but, when i try to open a message is showing like this file format corrupted ......my code on click of button on jsp is

strDate = strDate.substring(8,10) + strDate.substring(5,7) + strDate.substring(0,4) + "_" + strDate.substring(11,13) + strDate.substring(14,16)  + strDate.substring(17,19);
String path1=application.getRealPath("/")+ "EXCEL/TransactionsReport_"+ UserName +".xls";
response.setContentType ("application/vnd.ms-excel");
 String filename = "TransactionsReport_" + strDate + "_" + UserName + ".xls";
 response.setHeader ("Content-Disposition","attachment; filename="+filename);

 BufferedInputStream in=null;
    ServletOutputStream outs=null;
		byte[] buffer = new byte[1024]; 
		//int bit = 256;
		int i = 0;
    		try {
             in = new BufferedInputStream(new FileInputStream(new File (path1)));  
             outs=response.getOutputStream();
while ((i = in.read(buffer, 0, buffer.length)) != -1) {  
                  outs.write(buffer, 0, i);  
                  }  
                  outs.flush();  

            		} catch (IOException ioe) {
            			ioe.printStackTrace(System.out);
            		}
            	finally{
            		outs.close();
            		in.close();	
                }

but the generated code is giving a corrupted excel file

[mallikarjun dontamsetti]

It is working when i deployed it on web not in local system why?

[Rob Spoor]

You shouldn't use JSP files to display any binary file, including Excel files. Any whitespace between tags (like at the top, between import directives) can already be added to the output. That will cause corruption of binary files. Instead, use a servlet to display the binary file.

[mallikarjun dontamsetti]

thanks

[Rob Spoor]

You're welcome.

[Sachchidanand Singh]

Your problem will be solved

Add response.reset();  before before setContentType();

[Campbell Ritchie]

Welcome to the Ranch

Please explain a bit more, but don't expect a reply from the original poster; this is an old thread.

[Rob Spoor]

response.reset() will reset the entire response that has been built so far; the result is a clean response without any headers or body. There's an alternative in response.resetBuffer() that will only clear the body.

While those probably work, I stick by my statement from 9 years ago:

Rob Spoor wrote:You shouldn't use JSP files to display any binary file, including Excel files. Any whitespace between tags (like at the top, between import directives) can already be added to the output. That will cause corruption of binary files. Instead, use a servlet to display the binary file.

[Tim Holloway]

Rob Spoor wrote:You shouldn't use JSP files to display any binary file, including Excel files. Any whitespace between tags (like at the top, between import directives) can already be added to the output. That will cause corruption of binary files. Instead, use a servlet to display the binary file.

Repeated for emphasis.

JSPs are great for text files, including XML, JSON and YAML. For binary files, they are not. For one thing, the response buffers have been pre-loaded with headers related to the idea that text is coming out. The response.reset() tells the server to undo that work.

So in addition to being ill-suited for binary output, you're being less efficient by making it do and undo useless work. Servlets don't have that problem.