Using HttpClient inside JSF action method.

[Andrzej Folga]

Configuration: jboss 4.2.0 GA, MyFaces 1.5.0. I`m trying to call executeMethod(GetMethod) on my HttpClient class to receive xml file and then parse it using JAXB. The exception i`m recieving is:

11:36:12,859 ERROR [[Faces Servlet]] Servlet.service() for servlet Faces Servlet threw exception javax.servlet.ServletException: Exception while invoking expression #{Task.save} at javax.faces.webapp.FacesServlet.service(FacesServlet.java:154) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at com.bluemedia.topupInvoice.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:46) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:147) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:525) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:156) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:241) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:580) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:595)
My action method code is:

    public void save() throws NamingException, IOException, JAXBException {
 
        Invoice invoice;
 
        HttpClient httpClient = new HttpClient();
 
        httpClient.getState().setCredentials(
            new AuthScope(Common.TOPUP_REPORT_URL,Common.TOPUP_REPORT_PORT),
            new UsernamePasswordCredentials(Common.TOPUP_REPORT_USERNAME, Common.TOPUP_REPORT_PASSWORD)
        );
 
        GetMethod method = new GetMethod("http://"+ Common.TOPUP_REPORT_URL + "files/example.xml");
        method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER,
    new DefaultHttpMethodRetryHandler(3, false));
 
        method.setDoAuthentication( true );
 
        try {
              // Execute the method.
              int statusCode = httpClient.executeMethod(method);
            
              if (statusCode != HttpStatus.SC_OK) {
                System.err.println("Method failed: " + method.getStatusLine());
              }
 
              String xmlString = method.getResponseBodyAsString();
              DocumentFactory idf = new DocumentFactory();
              invoice = (Invoice) idf.unmarshal(xmlString);
        }
        finally {
          // Release the connection.
          method.releaseConnection();
        }
 
        return "saveTask";
    }

[Tim Holloway]

Hint: Never write try clauses that throw away the exception.

Add the following code before the "finally: clause:

} catch ( Exception ex ) { // or Throwable ex, if you prefer
   ex.printStackTrace();
// Next line is:
   } finally {

While I don't otherwise condone web apps printing to stdout, in Tomcat it will show up in one of the catalina output logs.

For a Real World app, I'd use proper logging and add error handling code to the app, but this will get you rolling.
[ December 06, 2007: Message edited by: Tim Holloway ]