invokerservlet.java

精通tomcat书籍原代码,希望大家共同学习

/*
 * Copyright 1999,2004 The Apache Software Foundation.
 * 
 * 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 org.apache.catalina.servlets;


import java.io.IOException;

import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.UnavailableException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.catalina.ContainerServlet;
import org.apache.catalina.Context;
import org.apache.catalina.Globals;
import org.apache.catalina.Wrapper;
import org.apache.catalina.util.StringManager;


/**
 * The default servlet-invoking servlet for most web applications,
 * used to serve requests to servlets that have not been registered
 * in the web application deployment descriptor.
 *
 * @author Craig R. McClanahan
 * @version $Revision: 302726 $ $Date: 2004-02-27 09:59:07 -0500 (Fri, 27 Feb 2004) $
 */

public final class InvokerServlet
    extends HttpServlet implements ContainerServlet {


    // ----------------------------------------------------- Instance Variables


    /**
     * The Context container associated with our web application.
     */
    private Context context = null;


    /**
     * The debugging detail level for this servlet.
     */
    private int debug = 0;


    /**
     * The string manager for this package.
     */
    private static StringManager sm =
        StringManager.getManager(Constants.Package);


    /**
     * The Wrapper container associated with this servlet.
     */
    private Wrapper wrapper = null;


    // ----------------------------------------------- ContainerServlet Methods


    /**
     * Return the Wrapper with which we are associated.
     */
    public Wrapper getWrapper() {

        return (this.wrapper);

    }


    /**
     * Set the Wrapper with which we are associated.
     *
     * @param wrapper The new wrapper
     */
    public void setWrapper(Wrapper wrapper) {

        this.wrapper = wrapper;
        if (wrapper == null)
            context = null;
        else
            context = (Context) wrapper.getParent();

    }


    // --------------------------------------------------------- Public Methods


    /**
     * Finalize this servlet.
     */
    public void destroy() {

        ;       // No actions necessary

    }


    /**
     * Process a GET request for the specified resource.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet-specified error occurs
     */
    public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
        throws IOException, ServletException {

        serveRequest(request, response);

    }


    /**
     * Process a HEAD request for the specified resource.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet-specified error occurs
     */
    public void doHead(HttpServletRequest request,
                       HttpServletResponse response)
        throws IOException, ServletException {

        serveRequest(request, response);

    }


    /**
     * Process a POST request for the specified resource.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet-specified error occurs
     */
    public void doPost(HttpServletRequest request,
                       HttpServletResponse response)
        throws IOException, ServletException {

        serveRequest(request, response);

    }


    /**
     * Initialize this servlet.
     */
    public void init() throws ServletException {

        // Ensure that our ContainerServlet properties have been set
        if ((wrapper == null) || (context == null))
            throw new UnavailableException
                (sm.getString("invokerServlet.noWrapper"));

        // Set our properties from the initialization parameters
        String value = null;
        try {
            value = getServletConfig().getInitParameter("debug");
            debug = Integer.parseInt(value);
        } catch (Throwable t) {
            ;
        }
        if (debug >= 1)
            log("init: Associated with Context '" + context.getPath() + "'");

    }



    // -------------------------------------------------------- Private Methods


    /**
     * Serve the specified request, creating the corresponding response.
     * After the first time a particular servlet class is requested, it will
     * be served directly (like any registered servlet) because it will have
     * been registered and mapped in our associated Context.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet-specified error occurs
     */
    public void serveRequest(HttpServletRequest request,
                             HttpServletResponse response)
        throws IOException, ServletException {

        // Disallow calling this servlet via a named dispatcher
        if (request.getAttribute(Globals.NAMED_DISPATCHER_ATTR) != null)
            throw new ServletException
                (sm.getString("invokerServlet.notNamed"));

        // Identify the input parameters and our "included" state
        String inRequestURI = null;
        String inServletPath = null;
        String inPathInfo = null;
        boolean included =
            (request.getAttribute(Globals.INCLUDE_REQUEST_URI_ATTR) != null);

        if (included) {
            inRequestURI =
                (String) request.getAttribute(Globals.INCLUDE_REQUEST_URI_ATTR);
            inServletPath =
                (String) request.getAttribute(Globals.INCLUDE_SERVLET_PATH_ATTR);
            inPathInfo =
                (String) request.getAttribute(Globals.INCLUDE_PATH_INFO_ATTR);
        } else {
            inRequestURI = request.getRequestURI();
            inServletPath = request.getServletPath();
            inPathInfo = request.getPathInfo();
        }
        if (debug >= 1) {
            log("included='" + included + "', requestURI='" +
                inRequestURI + "'");
            log("  servletPath='" + inServletPath + "', pathInfo='" +
                inPathInfo + "'");
        }

        // Make sure a servlet name or class name was specified