jahiafetcherbaseservice.java

java 写的一个新闻发布系统

//
//                                   ____.
//                       __/\ ______|    |__/\.     _______
//            __   .____|    |       \   |    +----+       \
//    _______|  /--|    |    |    -   \  _    |    :    -   \_________
//   \\______: :---|    :    :           |    :    |         \________>
//           |__\---\_____________:______:    :____|____:_____\
//                                      /_____|
//
//                 . . . i n   j a h i a   w e   t r u s t . . .
//

//
//  JahiaFetcherBaseServices
//  EV      11.01.2001
//
//
//  fetchServlet( jParams, servletPath )
//


package org.jahia.services.fetchers;

import java.io.*;
import javax.servlet.*;

import org.jahia.utils.*;       // JahiaConsole
import org.jahia.params.*;      // ParamBean
import org.jahia.services.applications.*;
import org.jahia.utils.*;

/**
 * Class JahiaFetcherBaseService
 *
 */
public class JahiaFetcherBaseService extends JahiaFetcherService {

    private static JahiaFetcherBaseService theObject = null;


    /**
     * constructor
     */
    protected JahiaFetcherBaseService () {
        JahiaConsole.println ("JahiaFetcherService", "***** Starting up the Jahia Fetcher Service *****");
    }


    /**
     * returns an instance of the fetcher service
     */
    public static synchronized JahiaFetcherBaseService getInstance () {
        if (theObject == null) {
            theObject = new JahiaFetcherBaseService ();
        }
        return theObject;
    }


    /**
     * fetches a servlet or JSP output
     *
     * @param        jParams             a ParamBean object (with request and response)
     * @param        servletPath         the servlet / jsp context path
     * @return       the servlet / jsp output
     */
    public String fetchServlet (ParamBean jParams, String servletPath) {
        ServletIncludeResponseWrapper responseWrapper = null;

        try {

            JahiaConsole.println ("Fetcher", "Dispatching to servlet path = [" + servletPath + "]");

            RequestDispatcher sessionDispatcher =
                    jParams.getContext ().getRequestDispatcher (servletPath);

            if (sessionDispatcher == null) {
                String errorMsg = "Error in fetchServlet : sessionDispatcher is null - error getting request dispatcher";
                JahiaConsole.println ("Error while fetching a servlet output", errorMsg);
                return "";
            }

            jParams.getResponse ().setContentType ("text/html");

            // Let's initialize the wrapper, that includes our specific PrintWriter, allowing us to redirect
            // output to a string object.
            responseWrapper = new ServletIncludeResponseWrapper (
                    jParams.getResponse (), false, null);

            if (responseWrapper == null) {
                String errorMsg = "Error in fetchServlet : responseWrapper is null - error getting response warpper";
                JahiaConsole.println ("Error while fetching a servlet output", errorMsg);
                return "";
            }

            ServletIncludeRequestWrapper requestWrapper =
                    new ServletIncludeRequestWrapper (jParams.getRequest ());

            // Let's now call the servlet and retrieve the result of it's processing
            sessionDispatcher.forward (requestWrapper, responseWrapper);

        } catch (ServletException se) {

            try {
                String generatedOutput = responseWrapper.getStringBuffer ();
                JahiaConsole.println ("JahiaFetcherBaseService.fetchServlet", generatedOutput);

            } catch (IOException ex) {
                JahiaConsole.printe ("Error while retrieving generated output", ex);
            }

            String errorMsg = "Error in fetchServlet : servlet exception occured (" + se.getMessage ();
            if (se.getRootCause () == null) {
                errorMsg += ")";
            } else {
                errorMsg += ",rootCause=" + se.getRootCause ().getMessage () + ")";
            }

            JahiaConsole.printe (errorMsg, se);
            return "";

        } catch (IOException ioe) {
            try {
                String generatedOutput = responseWrapper.getStringBuffer ();
                JahiaConsole.println ("JahiaFetcherBaseService.fetchServlet", generatedOutput);

            } catch (IOException ex) {
                JahiaConsole.printe ("Error while retrieving generated output", ex);
            }

            String errorMsg = "Error in fetchServlet : ioexception in servlet (" + ioe.getMessage () + ")";
            JahiaConsole.printe (errorMsg, ioe);
            return "";
        }

        String generatedOutput = "";
        try {
            generatedOutput = responseWrapper.getStringBuffer ();

        } catch (IOException ioe) {
            JahiaConsole.printe ("Error while retrieving generated output", ioe);
        }

        return generatedOutput;
    }

}