Error when downloading file to browser
I would really appreciate some answers on this one...
I have a page that allows the user to download a file that is stored in the database as a BLOB. The following exception is thrown when the download link is clicked. I can trace through my method to the point where the reponse is returning through the Seam filters, so I know that the method is returning the bytes associated with the file.
java.lang.IllegalStateException: Servlet response already use stream, Writer not possible at org.ajax4jsf.webapp.FilterServletResponseWrapper.getWriter(FilterServletResponseWrapper.java:226) at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:112) at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:112) at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:112) at com.sun.facelets.FaceletViewHandler.createResponseWriter(FaceletViewHandler.java:414) at com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:571) at org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:108) at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:216) at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:106) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:251) at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:144) ...
My page looks like this:
<h:panelGrid id="document" columns="2">
<h:outputLabel value="Location"/>
<h:outputText value="#{documentLocation.location}"/>
<h:outputLabel value="Upload Date"/>
<h:outputText value="#{documentLocation.uploadDate}"/>
<h:outputLabel value="Content Type"/>
<h:outputText value="#{documentLocation.contentType}"/>
<h:outputLabel value="Description"/>
<h:outputText value="#{documentLocation.notes}"/>
<h:panelGroup>
<s:link id="downloadDocument" value="Download"
action="#{documentManager.onDownload}"
view="/download.xhtml">
<f:param name="docId" value="#{documentLocation.id}"/>
</s:link>
</h:panelGroup>
</h:panelGrid>
The onDownload method looks like this:
public String onDownload()
{
System.out.println( "DocumentManagerAction.onDownload() called" );
System.out.println( "Value of doc id is " + docId );
HttpServletResponse response = ( HttpServletResponse ) facesContext.getExternalContext().getResponse();
response.setContentType( "application/pdf" );
try
{
byte[] docData = getDocumentData();
if ( docData != null && docData.length > 0 )
{
response.setContentLength( docData.length );
os.write( docData );
os.flush();
os.close();
System.out.println( "\nSuccess\n" );
}
facesContext.responseComplete();
}
catch ( Exception e )
{
System.out.println( "\nFailure : " + e.toString() + "\n" );
return null;
}
return "done";
}