Saving JSP output to a file

Question

I need to be able to save what a user sees on his browser, to a local file (where the web app runs).
The content is dynamic. It is being created using a JSP.
One way to write it to a local file would be to move the content creation from a JSP to a servlet and write to the HTTP response as well as to a file in the servlet.
That's going to make it look messy.
Any thoughts on how I could make this happen while continuing to use a JSP?

Answer 1

OK, so now I've tried it, it's essentially what is described in the J2EE tutorial:
/* File 1 */
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
* passes on a subclass of HttpServletResponseWrapper
* in order to replace the output writer.
public class OutReplacementFilter implements Filter {
  public void init(FilterConfig filterConfig) throws ServletException {  }
  public void destroy() {  }
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
              throws IOException, ServletException {
    //wrap the original response
    HttpServletResponse newResponse = new ReplacementHttpServletResponse((HttpServletResponse) response);
    //pass it to the resource
    chain.doFilter(request, newResponse);
    //get what the resource wrote
    String output = newResponse.toString();
    //put it to the output stream
    PrintWriter out = response.getWriter();
    out.write(output);
    out.close();
    //and then put it where ever else you like
    System.out.println(output);
/* File 2 */
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
* returns specialized writer to capture jsp output
public class ReplacementHttpServletResponse extends HttpServletResponseWrapper {
  private CharArrayWriter replacementWriter;
  public ReplacementHttpServletResponse (HttpServletResponse response) {
    super(response);
    replacementWriter = new CharArrayWriter();
  public PrintWriter getWriter() throws IOException {
    return new PrintWriter(replacementWriter);
  public String toString() {
    return replacementWriter.toString();
}This way is easy and few keystrokes, but buffers all the output until the filter chain returns.