defaultservlet.java

业界著名的tomcat服务器的最新6.0的源代码。

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.StringTokenizer;

import javax.naming.InitialContext;
import javax.naming.NameClassPair;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.DirContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.UnavailableException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;

import org.apache.catalina.Globals;
import org.apache.catalina.util.RequestUtil;
import org.apache.catalina.util.ServerInfo;
import org.apache.catalina.util.StringManager;
import org.apache.catalina.util.URLEncoder;
import org.apache.naming.resources.CacheEntry;
import org.apache.naming.resources.ProxyDirContext;
import org.apache.naming.resources.Resource;
import org.apache.naming.resources.ResourceAttributes;


/**
 * The default resource-serving servlet for most web applications,
 * used to serve static resources such as HTML pages and images.
 *
 * @author Craig R. McClanahan
 * @author Remy Maucherat
 * @version $Revision: 476992 $ $Date: 2006-11-20 01:17:55 +0100 (lun., 20 nov. 2006) $
 */

public class DefaultServlet
    extends HttpServlet {


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


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


    /**
     * The input buffer size to use when serving resources.
     */
    protected int input = 2048;


    /**
     * Should we generate directory listings?
     */
    protected boolean listings = false;


    /**
     * Read only flag. By default, it's set to true.
     */
    protected boolean readOnly = true;


    /**
     * The output buffer size to use when serving resources.
     */
    protected int output = 2048;


    /**
     * Array containing the safe characters set.
     */
    protected static URLEncoder urlEncoder;


    /**
     * Allow customized directory listing per directory.
     */
    protected String  localXsltFile = null;


    /**
     * Allow customized directory listing per instance.
     */
    protected String  globalXsltFile = null;


    /**
     * Allow a readme file to be included.
     */
    protected String readmeFile = null;


    /**
     * Proxy directory context.
     */
    protected ProxyDirContext resources = null;


    /**
     * File encoding to be used when reading static files. If none is specified
     * the platform default is used.
     */
    protected String fileEncoding = null;
    
    
    /**
     * Minimum size for sendfile usage in bytes.
     */
    protected int sendfileSize = 48 * 1024;
    
    
    /**
     * Full range marker.
     */
    protected static ArrayList FULL = new ArrayList();
    
    
    // ----------------------------------------------------- Static Initializer


    /**
     * GMT timezone - all HTTP dates are on GMT
     */
    static {
        urlEncoder = new URLEncoder();
        urlEncoder.addSafeCharacter('-');
        urlEncoder.addSafeCharacter('_');
        urlEncoder.addSafeCharacter('.');
        urlEncoder.addSafeCharacter('*');
        urlEncoder.addSafeCharacter('/');
    }


    /**
     * MIME multipart separation string
     */
    protected static final String mimeSeparation = "CATALINA_MIME_BOUNDARY";


    /**
     * JNDI resources name.
     */
    protected static final String RESOURCES_JNDI_NAME = "java:/comp/Resources";


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


    /**
     * Size of file transfer buffer in bytes.
     */
    protected static final int BUFFER_SIZE = 4096;


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


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


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

        if (getServletConfig().getInitParameter("debug") != null)
            debug = Integer.parseInt(getServletConfig().getInitParameter("debug"));

        if (getServletConfig().getInitParameter("input") != null)
            input = Integer.parseInt(getServletConfig().getInitParameter("input"));

        if (getServletConfig().getInitParameter("output") != null)
            output = Integer.parseInt(getServletConfig().getInitParameter("output"));

        listings = Boolean.parseBoolean(getServletConfig().getInitParameter("listings"));

        if (getServletConfig().getInitParameter("readonly") != null)
            readOnly = Boolean.parseBoolean(getServletConfig().getInitParameter("readonly"));

        if (getServletConfig().getInitParameter("sendfileSize") != null)
            sendfileSize = 
                Integer.parseInt(getServletConfig().getInitParameter("sendfileSize")) * 1024;

        fileEncoding = getServletConfig().getInitParameter("fileEncoding");

        globalXsltFile = getServletConfig().getInitParameter("globalXsltFile");
        localXsltFile = getServletConfig().getInitParameter("localXsltFile");
        readmeFile = getServletConfig().getInitParameter("readmeFile");

        // Sanity check on the specified buffer sizes
        if (input < 256)
            input = 256;
        if (output < 256)
            output = 256;

        if (debug > 0) {
            log("DefaultServlet.init:  input buffer size=" + input +
                ", output buffer size=" + output);
        }

        // Load the proxy dir context.
        resources = (ProxyDirContext) getServletContext()
            .getAttribute(Globals.RESOURCES_ATTR);
        if (resources == null) {
            try {
                resources =
                    (ProxyDirContext) new InitialContext()
                    .lookup(RESOURCES_JNDI_NAME);
            } catch (NamingException e) {
                // Failed
                throw new ServletException("No resources", e);
            }
        }

        if (resources == null) {
            throw new UnavailableException("No resources");
        }

    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Return the relative path associated with this servlet.
     *
     * @param request The servlet request we are processing
     */
    protected String getRelativePath(HttpServletRequest request) {

        // Are we being processed by a RequestDispatcher.include()?
        if (request.getAttribute(Globals.INCLUDE_REQUEST_URI_ATTR) != null) {
            String result = (String) request.getAttribute(
                                            Globals.INCLUDE_PATH_INFO_ATTR);
            if (result == null)
                result = (String) request.getAttribute(
                                            Globals.INCLUDE_SERVLET_PATH_ATTR);
            if ((result == null) || (result.equals("")))
                result = "/";
            return (result);
        }

        // No, extract the desired path directly from the request
        String result = request.getPathInfo();
        if (result == null) {
            result = request.getServletPath();
        }
        if ((result == null) || (result.equals(""))) {
            result = "/";
        }
        return (result);

    }


    /**
     * 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
     */
    protected void doGet(HttpServletRequest request,
                         HttpServletResponse response)
        throws IOException, ServletException {

        // Serve the requested resource, including the data content
        serveResource(request, response, true);

    }


    /**
     * 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
     */
    protected void doHead(HttpServletRequest request,
                          HttpServletResponse response)
        throws IOException, ServletException {

        // Serve the requested resource, without the data content
        serveResource(request, response, false);

    }


    /**
     * 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
     */
    protected void doPost(HttpServletRequest request,
                          HttpServletResponse response)
        throws IOException, ServletException {
        doGet(request, response);
    }


    /**
     * Process a POST request for the specified resource.
     *
     * @param req The servlet request we are processing
     * @param resp The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet-specified error occurs
     */