Text File download with RichFaces
Hi,
I am using JBOSS Seam v2.0.0 and RichFaces 3.1.2
I am trying to make the following happen:
I have a page containing a commandLink (or commandButton) and when a user clicks on this, I want a file to be downloaded. This file will be generated by a backing bean method.
I have set my code up like this:
<h:commandLink immediate="true"
action="#{searchManager.generateVCalendar}">
<h:graphicImage value="/images/vcalendar.bmp"/>
</h:commandLink>
and
public String generateVCalendar()
{
String fileContents = "text file";
log.debug("generateVCalendar");
if (!facesContext.getResponseComplete())
{
String fileName = "export.wri";
try
{
ServletContext servletContext = (ServletContext) facesContext.getExternalContext().getContext();
HttpServletResponse response = (HttpServletResponse) facesContext.getExternalContext().getResponse();
String encoding = response.getCharacterEncoding();
byte[] bytes = fileContents.getBytes(encoding);
response.setContentType("text/plain");
StringBuffer disposition = new StringBuffer("attachment; filename=\"");
disposition.append("Plato-Termin");
disposition.append(".txt");
disposition.append("\"");
response.setHeader("Content-Disposition", disposition.toString());
response.setContentLength(bytes.length);
ServletOutputStream out = null;
out = response.getOutputStream();
out.write(bytes);
out.flush();
out.close();
facesContext.getApplication().getStateManager().saveSerializedView(facesContext);
facesContext.responseComplete();
}
catch (Exception e)
{
log.error("generateVCalendar Exception: " + e.getMessage());
}
}
return null;
}However, when I click on the link, I get:
java.lang.NullPointerException java.util.regex.Matcher.getTextLength(Matcher.java:1127) java.util.regex.Matcher.reset(Matcher.java:284) java.util.regex.Matcher.<init>(Matcher.java:205) java.util.regex.Pattern.matcher(Pattern.java:879) org.ajax4jsf.webapp.ParserConfig.getParser(ParserConfig.java:28) org.ajax4jsf.webapp.ConfigurableXMLFilter.getParser(ConfigurableXMLFilter.java:109) org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:259) org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:281) org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:60) org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:58) org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69) org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158) org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
Can anyone help me as to why this is not working?
Or, is there a better way to do a file download. e.g. <a4j:mediaOutput>? I have seen examples for this but these always seem to be for images embedded into a page.
Thanks for your help,
Richard.
