Jetty example source code file (DispatchServlet.java)

This example Jetty source code file (DispatchServlet.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Jetty tags/keywords

dispatch=forward, dispatch=include, h1, h1, hr, http, httpservletresponse, io, ioexception, printwriter, printwriter, request, requestdispatcher, requestdispatcher, response, servlet, servletexception, string, string

The Jetty DispatchServlet.java source code

// ========================================================================
// Copyright 1996-2005 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at 
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ========================================================================

package com.acme;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

import org.mortbay.util.URIUtil;


/* ------------------------------------------------------------ */
/** Test Servlet RequestDispatcher.
 * 
 * @author Greg Wilkins (gregw)
 */
public class DispatchServlet extends HttpServlet
{
    /* ------------------------------------------------------------ */
    String pageType;

    /* ------------------------------------------------------------ */
    public void init(ServletConfig config) throws ServletException
    {
        super.init(config);
    }

    /* ------------------------------------------------------------ */
    public void doPost(HttpServletRequest sreq, HttpServletResponse sres) throws ServletException, IOException
    {
        doGet(sreq, sres);
    }

    /* ------------------------------------------------------------ */
    public void doGet(HttpServletRequest sreq, HttpServletResponse sres) throws ServletException, IOException
    {
        if (sreq.getParameter("wrap") != null)
        {
            sreq= new HttpServletRequestWrapper(sreq);
            sres= new HttpServletResponseWrapper(sres);
        }
        
        if (sreq.getParameter("session") != null)
            sreq.getSession(true);

        String prefix=
            sreq.getContextPath() != null ? sreq.getContextPath() + sreq.getServletPath() : sreq.getServletPath();

        String info;

        if (sreq.getAttribute("javax.servlet.include.servlet_path") != null)
            info= (String)sreq.getAttribute("javax.servlet.include.path_info");
        else
            info= sreq.getPathInfo();

        if (info == null)
            info= "NULL";

        if (info.startsWith("/includeW/"))
        {
            sres.setContentType("text/html");
            info= info.substring(9);
            if (info.indexOf('?') < 0)
                info += "?Dispatch=include";
            else
                info += "&Dispatch=include";
            
            PrintWriter pout= null;
            pout= sres.getWriter();
            pout.write("<H1>Include (writer): " + info + "
");
            
            RequestDispatcher dispatch= getServletContext().getRequestDispatcher(info);
            if (dispatch == null)
            {
                pout= sres.getWriter();
                pout.write("<H1>Null dispatcher");
            }
            else
                dispatch.include(sreq, sres);
            
            pout.write("<HR>
-- Included (writer)
");
        }
        else if (info.startsWith("/includeS/"))
        {
            sres.setContentType("text/html");
            info= info.substring(9);
            if (info.indexOf('?') < 0)
                info += "?Dispatch=include";
            else
                info += "&Dispatch=include";
            
            OutputStream out= null;
            out= sres.getOutputStream();
            out.write(("<H1>Include (outputstream): " + info + "
").getBytes());
            
            RequestDispatcher dispatch= getServletContext().getRequestDispatcher(info);
            if (dispatch == null)
            {
                out= sres.getOutputStream();
                out.write("<H1>Null dispatcher".getBytes());
            }
            else
                dispatch.include(sreq, sres);
            
            out.write("<HR>
-- Included (outputstream)
".getBytes());
            
        }
        else if (info.startsWith("/forward/"))
        {
            info= info.substring(8);
            if (info.indexOf('?') < 0)
                info += "?Dispatch=forward";
            else
                info += "&Dispatch=forward";
            RequestDispatcher dispatch= getServletContext().getRequestDispatcher(info);
            if (dispatch != null)
            {
                ServletOutputStream out =sres.getOutputStream();
                out.print("Can't see this");
                dispatch.forward(sreq, sres);
                try
                {
                    out.println("IOException");
                    throw new IllegalStateException();
                }
                catch(IOException e)
                {}
            }
            else
            {
                sres.setContentType("text/html");
                PrintWriter pout= sres.getWriter();
                pout.write("<H1>No dispatcher for: " + info + "
");
                pout.flush();
            }
        }
        else if (info.startsWith("/forwardC/"))
        {
            info= info.substring(9);
            if (info.indexOf('?') < 0)
                info += "?Dispatch=forward";
            else
                info += "&Dispatch=forward";
            
            String cpath= info.substring(0, info.indexOf('/', 1));
            info= info.substring(cpath.length());
            
            ServletContext context= getServletContext().getContext(cpath);
            RequestDispatcher dispatch= context.getRequestDispatcher(info);
            
            if (dispatch != null)
            {
                dispatch.forward(sreq, sres);
            }
            else
            {
                sres.setContentType("text/html");
                PrintWriter pout= sres.getWriter();
                pout.write("<H1>No dispatcher for: " + cpath + URIUtil.SLASH + info + "
");
                pout.flush();
            }
        }
        else if (info.startsWith("/includeN/"))
        {
            sres.setContentType("text/html");
            info= info.substring(10);
            if (info.indexOf(URIUtil.SLASH) >= 0)
                info= info.substring(0, info.indexOf(URIUtil.SLASH));
            
            PrintWriter pout;
            if (info.startsWith("/null"))
                info= info.substring(5);
            else
            {
                pout= sres.getWriter();
                pout.write("<H1>Include named: " + info + "
");
            }
            
            RequestDispatcher dispatch= getServletContext().getNamedDispatcher(info);
            if (dispatch != null)
                dispatch.include(sreq, sres);
            else
            {
                pout= sres.getWriter();
                pout.write("<H1>No servlet named: " + info + "");
            }
            
            pout= sres.getWriter();
            pout.write("<HR>
Included ");
        }
        else if (info.startsWith("/forwardN/"))
        {
            info= info.substring(10);
            if (info.indexOf(URIUtil.SLASH) >= 0)
                info= info.substring(0, info.indexOf(URIUtil.SLASH));
            RequestDispatcher dispatch= getServletContext().getNamedDispatcher(info);
            if (dispatch != null)
                dispatch.forward(sreq, sres);
            else
            {
                sres.setContentType("text/html");
                PrintWriter pout= sres.getWriter();
                pout.write("<H1>No servlet named: " + info + "
");
                pout.flush();
            }
        }
        else
        {
            sres.setContentType("text/html");
            PrintWriter pout= sres.getWriter();
            pout.write(
                    "<H1>Dispatch URL must be of the form: "
                    + "<PRE>"
                    + prefix
                    + "/includeW/path\n"
                    + prefix
                    + "/includeS/path\n"
                    + prefix
                    + "/forward/path\n"
                    + prefix
                    + "/includeN/name\n"
                    + prefix
                    + "/forwardC/_context/path\n</PRE>");
        }
        
    }

    /* ------------------------------------------------------------ */
    public String getServletInfo()
    {
        return "Include Servlet";
    }

    /* ------------------------------------------------------------ */
    public synchronized void destroy()
    {
    }

}