jspservlet.java

低版本的tomcat 对于有些老版本的应用还真的需要老版的中间件

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written 
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache"
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */ 

package org.apache.jasper.servlet;

import javax.servlet.Servlet;
import javax.servlet.ServletContext;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.SingleThreadModel;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.HttpJspPage;
import javax.servlet.jsp.JspFactory;

import java.util.Hashtable;
import java.util.Enumeration;
import java.io.File;
import java.io.PrintWriter;
import java.io.IOException;
import java.io.FileNotFoundException;

import org.apache.jasper.JasperException;
import org.apache.jasper.Constants;
import org.apache.jasper.Options;
import org.apache.jasper.EmbededServletOptions;
import org.apache.jasper.JspCompilationContext;
import org.apache.jasper.JspEngineContext;
import org.apache.jasper.compiler.Mangler;
import org.apache.jasper.runtime.*;

import org.apache.jasper.compiler.Compiler;

import org.apache.tomcat.logging.Logger;

/**
 * The JSP engine (a.k.a Jasper)! 
 *
 * @author Anil K. Vijendran
 * @author Harish Prabandham
 * @author Marc A. Saegesser
 */
public class JspServlet extends HttpServlet {

    /**
     * Adds reference counting to the JSP implementation servlet.  This
     * is required to handle the case where a JSP implementation servlet
     * is executing requests on several threads when a new implementation
     * arrives (the JSP source was updated).  We need to wait until all
     * the requests complete before calling the implementation servlet's
     * destroy() method.
     */
    class JspCountedServlet extends HttpServlet
    {
        private Servlet servlet = null;
        private int threadCount = 0;
        private boolean destroyed = false;

        public JspCountedServlet(Servlet servlet)
        {
            this.servlet = servlet;
        }

        public void init(ServletConfig config) throws ServletException, JasperException
        {
            try{
                servlet.init(config);
            }catch(NullPointerException e){
                throw new JasperException(e);
            }
        }

        public void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException, JasperException
        {
            try{
                incrementCount();
                servlet.service(req, res);
            }catch(NullPointerException e){
                throw new JasperException(e);
            }finally{
                decrementCount();
            }
        }

        /*
         * Flags this servlet for destrction once all active requests have completed.
         * After calling this method it is invalid to call service().
         */
        public void destroy()
        {
            destroyed = true;
            if(getCount() == 0)
                doDestroy();
        }

        private void doDestroy()
        {
            try{
                servlet.destroy();
                servlet = null;
            }catch(NullPointerException e){
            }
        }

        private synchronized void incrementCount()
        {
            threadCount++;
        }

        private synchronized void decrementCount()
        {
            if(threadCount <= 0){
                Constants.message("jsp.error.badcount", Logger.ERROR);
                return;
            }

            --threadCount;
            if(threadCount == 0 && destroyed)
                doDestroy();
        }

        private synchronized int getCount()
        {
            return threadCount;
        }
    }

    class JspServletWrapper {
        JspCountedServlet theServlet;
        String jspUri;
        boolean isErrorPage;
        Class servletClass;

        JspServletWrapper(String jspUri, boolean isErrorPage) {
            this.jspUri = jspUri;
            this.isErrorPage = isErrorPage;
            this.theServlet = null;
        }

        public synchronized void instantiateServlet(Class servletClass) throws JasperException, ServletException
        {
            try {
                this.servletClass = servletClass;

                // If we're replacing an existing JSP Implementation class, then
                // schedule it for destruction
                if(theServlet != null)
                    theServlet.destroy();

                // Create an instance of the JSP implementation class
                Servlet servlet = (Servlet) servletClass.newInstance();
                // Set the class loader
                if(servlet instanceof HttpJspBase) {
                    ((HttpJspBase)servlet).setClassLoader(JspServlet.this.parentClassLoader);
                }

                // Wrap this servlet in a counted servlet
                theServlet = new JspCountedServlet(servlet);

                // Call the JSP Implementation servlet's init() method.  This
                // will cause the page's jspInit() method to be invoked if one exists.
                theServlet.init(JspServlet.this.config);

            } catch(Exception ex) {
                throw new JasperException(ex);
            }

        }

        public synchronized Servlet getServlet()
        {
            return theServlet;
        }

        public synchronized boolean isInstantiated()
        {
            return theServlet != null;
        }

        private void loadIfNecessary(HttpServletRequest req, HttpServletResponse res) 
        throws JasperException, ServletException, FileNotFoundException 
        {
            // First try context attribute; if that fails then use the 
            // classpath init parameter. 

            // Should I try to concatenate them if both are non-null?

            String cp = (String) context.getAttribute(Constants.SERVLET_CLASSPATH);

            String accordingto;

            if(cp == null || cp.equals("")) {
                accordingto = "according to the init parameter";
                cp = options.getClassPath();
            } else
                accordingto = "according to the Servlet Engine";

            Constants.message("jsp.message.cp_is", 
                              new Object[] { 
                                  accordingto,
                                  cp == null ? "" : cp
                              }, 
                              Logger.INFORMATION);

            loadJSP(jspUri, cp, isErrorPage, req, res);
        }

        public void service(HttpServletRequest request, 
                            HttpServletResponse response,
                            boolean precompile)
        throws ServletException, IOException, FileNotFoundException 
        {
            Servlet servlet = null;
            try {
                loadIfNecessary(request, response);
                servlet = getServlet();

                // If a page is to only to be precompiled return.
                if(precompile)
                    return;

                if(servlet instanceof SingleThreadModel) {
                    // sync on the wrapper so that the freshness
                    // of the page is determined right before servicing
                    synchronized (this) {
                        servlet.service(request, response);
                    }
                } else {
                    servlet.service(request, response);
                }

            } catch(FileNotFoundException ex) {
                try {
                    if(insecure_TMI) {
                        response.sendError(HttpServletResponse.SC_NOT_FOUND, 
                                           Constants.getString
                                           ("jsp.error.file.not.found.TMI", 
                                            new Object[] {
                                                ex.getMessage()
                                            }));
                    } else {
                        response.sendError(HttpServletResponse.SC_NOT_FOUND, 
                                           Constants.getString
                                           ("jsp.error.file.not.found", 
                                            new Object[] {
                                                // Too Much Information -- ex.getMessage()
                                            }));
                    }
                } catch(IllegalStateException ise) {
                    // logs are presumed to be secure, thus the TMI info can be logged
                    Constants.jasperLog.log(Constants.getString
                                            ("jsp.error.file.not.found.TMI",
                                             new Object[] {
                                                 ex.getMessage()
                                             }), ex,
                                            Logger.ERROR);
                    // rethrow FileNotFoundException so someone higher up can handle
                    if(insecure_TMI)
                        throw ex;
                    else
                        throw new FileNotFoundException(Constants.getString
                                                        ("jsp.error.file.not.found", 
                                                         new Object[] {
                                                             // Too Much Information -- ex.getMessage()
                                                         }));
                }
                return;
            }
        }

        public void destroy()
        {
            if(theServlet != null)
                theServlet.destroy();
        }
    }