freemarkerservlet.java

freemaker安装软件

/*
 * Copyright (c) 2003 The Visigoth Software Society. 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 acknowledgement:
 *       "This product includes software developed by the
 *        Visigoth Software Society (http://www.visigoths.org/)."
 *    Alternately, this acknowledgement may appear in the software itself,
 *    if and wherever such third-party acknowledgements normally appear.
 *
 * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the 
 *    project contributors may 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 "FreeMarker" or "Visigoth"
 *    nor may "FreeMarker" or "Visigoth" appear in their names
 *    without prior written permission of the Visigoth Software Society.
 *
 * 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 VISIGOTH SOFTWARE SOCIETY 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 Visigoth Software Society. For more
 * information on the Visigoth Software Society, please see
 * http://www.visigoths.org/
 */

package freemarker.ext.servlet;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Enumeration;
import java.util.GregorianCalendar;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import freemarker.cache.WebappTemplateLoader;
import freemarker.core.Configurable;
import freemarker.ext.jsp.TaglibFactory;
import freemarker.log.Logger;
import freemarker.template.Configuration;
import freemarker.template.ObjectWrapper;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import freemarker.template.TemplateExceptionHandler;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.utility.StringUtil;
import java.util.Locale;

/**
 * <p>This is a general-purpose FreeMarker view servlet.</p>
 * 
 * <p>The main features are:
 * 
 * <ul>
 * 
 * <li>It makes all request, request parameters, session, and servlet
 * context attributes available to templates through <code>Request</code>,
 * <code>RequestParameters</code>, <code>Session</code>, and <code>Application</code>
 * variables.
 * 
 * <li>The scope variables are also available via automatic scope discovery. That is,
 * writing <code>Application.attrName</code>, <code>Session.attrName</code>,
 * <code>Request.attrName</code> is not mandatory; it's enough to write <code>attrName</code>,
 * and if no such variable was created in the template, it will search the
 * variable in <code>Request</code>, and then in <code>Session</code>,
 * and finally in <code>Application</code>.  
 * 
 * <li>It creates a variable with name <code>JspTaglibs</code>, that can be used
 * to load JSP taglibs. For example:<br>
 * <code>&lt;#assign tiles=JspTaglibs["/WEB-INF/struts-tiles.tld"]></code>
 * 
 * </ul>
 * 
 * <p>The servlet will rethrow the errors occurring during template processing,
 * wrapped into <code>ServletException</code>, except if the class name of the
 * class set by the <code>template_exception_handler</code> contains the
 * substring <code>"Debug"</code>. If it contains <code>"Debug"</code>, then it
 * is assumed that the template exception handler prints the error message to the
 * page, thus <code>FreemarkerServlet</code> will suppress the  exception, and
 * logs the problem with the servlet logger
 * (<code>javax.servlet.GenericServlet.log(...)</code>). 
 * 
 * <p>Supported init-params are:</p>
 * 
 * <ul>
 * 
 * <li><strong>TemplatePath</strong> specifies the location of the templates.
 * By default, this is interpreted as web application directory relative URI.<br>
 * Alternatively, you can prepend it with <tt>file://</tt> to indicate a literal
 * path in the file system (i.e. <tt>file:///var/www/project/templates/</tt>). 
 * Note that three slashes were used to specify an absolute path.<br>
 * Also, you can prepend it with <tt>class://path/to/template/package</tt> to
 * indicate that you want to load templates from the specified package
 * accessible through the classloader of the servlet.<br>
 * Default value is <tt>class://</tt> (that is, the root of the class hierarchy).
 * <i>Note that this default is different than the default in FreeMarker 1.x, when
 * it defaulted <tt>/</tt>, that is to loading from the webapp root directory.</i></li>
 * 
 * <li><strong>NoCache</strong> if set to true, generates headers in the response
 * that advise the HTTP client not to cache the returned page.
 * The default is <tt>false</tt>.</li>
 * 
 * <li><strong>ContentType</strong> if specified, response uses the specified
 * Content-type HTTP header. The value may include the charset (e.g.
 * <tt>"text/html; charset=ISO-8859-1"</tt>). If not specified, <tt>"text/html"</tt>
 * is used. If the charset is not specified in this init-param, then the charset
 * (encoding) of the actual template file will be used (in the response HTTP header
 * and for encoding the output stream). Note that this setting can be overridden
 * on a per-template basis by specifying a custom attribute named 
 * <tt>content_type</tt> in the <tt>attributes</tt> parameter of the 
 * <tt>&lt;#ftl></tt> directive. 
 * </li>
 * 
 * <li>The following init-params are supported only for backward compatibility, and
 * their usage is discouraged: TemplateUpdateInterval, DefaultEncoding,
 * ObjectWrapper, TemplateExceptionHandler. Use setting init-params such as
 * object_wrapper instead. 
 * 
 * <li>Any other init-param will be interpreted as <code>Configuration</code>
 * level setting. See {@link Configuration#setSetting}</li>
 * 
 * </ul>
 * 
 * @author Attila Szegedi
 * @version $Id: FreemarkerServlet.java,v 1.82.2.5 2006/06/21 13:02:01 ddekany Exp $
 */

public class FreemarkerServlet extends HttpServlet
{
    private static final Logger logger = Logger.getLogger("freemarker.servlet");
    
    public static final long serialVersionUID = -2440216393145762479L;

    private static final String INITPARAM_TEMPLATE_PATH = "TemplatePath";
    private static final String INITPARAM_NOCACHE = "NoCache";
    private static final String INITPARAM_CONTENT_TYPE = "ContentType";
    private static final String DEFAULT_CONTENT_TYPE = "text/html";
    private static final String INITPARAM_DEBUG = "Debug";
    
    private static final String DEPR_INITPARAM_TEMPLATE_DELAY = "TemplateDelay";
    private static final String DEPR_INITPARAM_ENCODING = "DefaultEncoding";
    private static final String DEPR_INITPARAM_OBJECT_WRAPPER = "ObjectWrapper";
    private static final String DEPR_INITPARAM_WRAPPER_SIMPLE = "simple";
    private static final String DEPR_INITPARAM_WRAPPER_BEANS = "beans";
    private static final String DEPR_INITPARAM_WRAPPER_JYTHON = "jython";
    private static final String DEPR_INITPARAM_TEMPLATE_EXCEPTION_HANDLER = "TemplateExceptionHandler";
    private static final String DEPR_INITPARAM_TEMPLATE_EXCEPTION_HANDLER_RETHROW = "rethrow";
    private static final String DEPR_INITPARAM_TEMPLATE_EXCEPTION_HANDLER_DEBUG = "debug";
    private static final String DEPR_INITPARAM_TEMPLATE_EXCEPTION_HANDLER_HTML_DEBUG = "htmlDebug";
    private static final String DEPR_INITPARAM_TEMPLATE_EXCEPTION_HANDLER_IGNORE = "ignore";
    private static final String DEPR_INITPARAM_DEBUG = "debug";

    public static final String KEY_REQUEST = "Request";
    public static final String KEY_REQUEST_PRIVATE = "__FreeMarkerServlet.Request__";
    public static final String KEY_REQUEST_PARAMETERS = "RequestParameters";
    public static final String KEY_SESSION = "Session";
    public static final String KEY_APPLICATION = "Application";
    public static final String KEY_APPLICATION_PRIVATE = "__FreeMarkerServlet.Application__";
    public static final String KEY_JSP_TAGLIBS = "JspTaglibs";

    // Note these names start with dot, so they're essentially invisible from
    // a freemarker script.
    private static final String ATTR_REQUEST_MODEL = ".freemarker.Request";
    private static final String ATTR_REQUEST_PARAMETERS_MODEL =
        ".freemarker.RequestParameters";
    private static final String ATTR_SESSION_MODEL = ".freemarker.Session";
    private static final String ATTR_APPLICATION_MODEL =
        ".freemarker.Application";
    private static final String ATTR_JSP_TAGLIBS_MODEL =
        ".freemarker.JspTaglibs";

    private static final String EXPIRATION_DATE;

    static {
        // Generate expiration date that is one year from now in the past
        GregorianCalendar expiration = new GregorianCalendar();
        expiration.roll(Calendar.YEAR, -1);
        SimpleDateFormat httpDate =
            new SimpleDateFormat(
                "EEE, dd MMM yyyy HH:mm:ss z",
                java.util.Locale.US);
        EXPIRATION_DATE = httpDate.format(expiration.getTime());
    }

    private String templatePath;
    private boolean nocache;
    protected boolean debug;
    private Configuration config;
    private ObjectWrapper wrapper;
    private String contentType;
    private boolean noCharsetInContentType;
    
    public void init() throws ServletException {
        try {
            config = createConfiguration();
            
            // Set defaults:
            config.setTemplateExceptionHandler(TemplateExceptionHandler.HTML_DEBUG_HANDLER);
            contentType = DEFAULT_CONTENT_TYPE;
            
            // Process object_wrapper init-param out of order: 
            wrapper = createObjectWrapper();
            if (logger.isDebugEnabled()) {
                logger.debug("Using object wrapper of class " + wrapper.getClass().getName());
            }
            config.setObjectWrapper(wrapper);
            
            // Process TemplatePath init-param out of order:
            templatePath = getInitParameter(INITPARAM_TEMPLATE_PATH);
            if (templatePath == null)
                templatePath = "class://";
            if (templatePath.startsWith("class://")) {
                // substring(7) is intentional as we "reuse" the last slash
                config.setClassForTemplateLoading(
                        getClass(),
                        templatePath.substring(7));
            } else {
                if (templatePath.startsWith("file://")) {
                    templatePath = templatePath.substring(7);
                    config.setDirectoryForTemplateLoading(new File(templatePath));
                } else {
                    config.setTemplateLoader(new WebappTemplateLoader(this.getServletContext(), templatePath));