Download file problem for binary data?

Question

Dear All,
I have wrote a jsp file to do download page. I have used a piece of code from the JDC to this. This code will prompt the download dialog box each time user clicks the download button. The code itself will set the content type for different application. The code is like below:
try
java.io.File fileobj = new java.io.File(strFolder + strFile);
response.setContentType(application.getMimeType(fileobj.getName()));
response.setHeader("Content-Disposition","attachment; filename=\""
+ strFile + "\"");
java.io.FileInputStream in = new java.io.FileInputStream(fileobj);
int ch;
while ((ch = in.read()) != -1) {
out.write(ch);
out.flush();
in.close();
} catch(Exception e)
The code can download and handle text file correctly when it is openned in the text editor or inside the IE. But when a PDF file or Image is downloaded and openned in the PDF viewer or image viewer, it is corrupted and cannot be viewed. What is the problem? Any ideas?
So, I wonder this code can handle binary data or not. It is seen like there is no different code to handle text and binary data in Java/Jsp.
Thank you very much!
Best Regards,
Rockyu Lee
          

Answer 1

Add following lines to .tld file (custom tag definition)
<tag>
<name>downloadbinary</name>
<tagclass>org.rampally.DownloadBinaryTag</tagclass>
<bodycontent>JSP</bodycontent>
</tag>
Add following line to JSP files.
In JSP, keep one line of source. Make sure that there are no space and additional line feeds at the any where
in the JSP files except JSP tags.
<%@ taglib uri="/WEB-INF/taglibs/mb.tld" prefix="mytags" %>
<mytags:downloadbinary />
I am hoping that you have all required parameters such as fileName to download, etc.
in your session or request object.
Tag class ....
public class DownloadBinaryTag extends TagSupport {
     public int doEndTag() throws JspException {
          // TODO: get binary data from filename or
          // binary data buffer from datase.
          // I am making it simple .. assume that it is a request parameter for
          // you test easily.
          String fileName = request.getParameter( "filename" );
          java.io.File file = new java.io.File( fileName);
          java.io.DataInputStream dis;
          try {
               dis = new java.io.DataInputStream(new FileInputStream(fileName));
          } catch (FileNotFoundException e) {
               // do error handling ...
               return EVAL_PAGE;
          BinaryUtil.sendBinaryFile( dis, (HttpServletResponse) pageContext.getResponse(), contentType );
          return EVAL_PAGE;
public class BinaryUtil
     static public void sendBinaryFile( DataInputStream dis,
                              HttpServletResponse response,
                              String contentType ) {
          try {
               response.setContentType(contentType);
               String fileName="test.pdf";
               response.setHeader("Content-disposition", "inline; filename=" + newFileName );
               ServletOutputStream sout = response.getOutputStream();
               int len;
               byte[] data = new byte[128 * 1024];
               while ((len = dis.read(data, 0, 128 * 1024)) >= 0)
                    sout.write(data, 0, len);
               sout.flush();
               sout.close();
          } catch (Exception e) {
               System.out.println(e.getMessage());
     static public void sendBinaryFile( byte[] data,
                              HttpServletResponse response,
                              String contentType ) {
          try {
               response.setContentType(contentType);
               String fileName="test.pdf";
               response.setHeader("Content-disposition", "inline; filename=" + newFileName );
               ServletOutputStream sout = response.getOutputStream();
               sout.write(data);
               sout.flush();
               sout.close();
          } catch (Exception e) {
               System.out.println(e.getMessage());
You may have to change 'inline' to 'attachment' if you do not want IE to inline the document.
That's all!!.. Hope this helps...!