Output a binary stream from a JSP

Output a binary stream from a JSP

You can't.

From JSP, only character stream should be used.

JSP pages were designed for *text* output. The "out" object is a Writer, which means it will play games with text encoding.

For binary output, like PDF or dynamically generated GIF, it's a better idea to use a servlet.

Having said that, since a JSP will be converted to a servlet, it's possible to modifed the output stream.

[image.jsp]

<%@ page import="java.io.*" %>
<%@ page import="java.net.*" %>
<%@page contentType="image/gif" %><%
    OutputStream o = response.getOutputStream();
    InputStream is = 
      new URL("http://myserver/myimage.gif").getInputStream();
    byte[] buf = new byte[32 * 1024]; // 32k buffer
    int nRead = 0;
    while( (nRead=is.read(buf)) != -1 ) {
        o.write(buf, 0, nRead);
    }
    o.flush();
    o.close();// *important* to ensure no more jsp output
    return; 
%>

Thanks to Benjamin Grant for the bug fix.