freemarkerservlet.java

freemaker安装软件

                (HttpRequestHashModel) request.getAttribute(ATTR_REQUEST_MODEL);
            if (requestModel == null || requestModel.getRequest() != request)
            {
                requestModel = new HttpRequestHashModel(request, response, wrapper);
                request.setAttribute(ATTR_REQUEST_MODEL, requestModel);
                request.setAttribute(
                    ATTR_REQUEST_PARAMETERS_MODEL,
                    createRequestParametersHashModel(request));
            }
            params.putUnlistedModel(KEY_REQUEST, requestModel);
            params.putUnlistedModel(KEY_REQUEST_PRIVATE, requestModel);
    
            // Create hash model wrapper for request parameters
            HttpRequestParametersHashModel requestParametersModel =
                (HttpRequestParametersHashModel) request.getAttribute(
                    ATTR_REQUEST_PARAMETERS_MODEL);
            params.putUnlistedModel(KEY_REQUEST_PARAMETERS, requestParametersModel);
            return params;
        } catch (ServletException e) {
            throw new TemplateModelException(e);
        } catch (IOException e) {
            throw new TemplateModelException(e);
        }
    }

    /**
     * Maps the request URL to a template path that is passed to 
     * {@link Configuration#getTemplate(String, Locale)}. You can override it
     * (i.e. to provide advanced rewriting capabilities), but you are strongly
     * encouraged to call the overridden method first, then only modify its
     * return value. 
     * @param request the currently processed request
     * @return a String representing the template path
     */
    protected String requestUrlToTemplatePath(HttpServletRequest request)
    {
        // First, see if it is an included request
        String includeServletPath  = (String) request.getAttribute("javax.servlet.include.servlet_path");
        if(includeServletPath != null)
        {
            // Try path info; only if that's null (servlet is mapped to an
            // URL extension instead of to prefix) use servlet path.
            String includePathInfo = (String) request.getAttribute("javax.servlet.include.path_info");
            return includePathInfo == null ? includeServletPath : includePathInfo;
        } 
        // Seems that the servlet was not called as the result of a 
        // RequestDispatcher.include(...). Try pathInfo then servletPath again,
        // only now directly on the request object:
        String path = request.getPathInfo();
        if (path != null) return path;
        path = request.getServletPath();
        if (path != null) return path;
        // Seems that it is a servlet mapped with prefix, and there was no extra path info.
        return "";
    }

    /**
     * Called as the first step in request processing, before the templating mechanism
     * is put to work. By default does nothing and returns false. This method is
     * typically overridden to manage serving of non-template resources (i.e. images)
     * that reside in the template directory.
     * @param request the HTTP request
     * @param response the HTTP response
     * @return true to indicate this method has processed the request entirely,
     * and that the further request processing should not take place.
     */
    protected boolean preprocessRequest(
        HttpServletRequest request,
        HttpServletResponse response)
            throws ServletException, IOException {
        return false;
    }

    /**
     * This method is called from {@link #init()} to create the
     * FreeMarker configuration object that this servlet will use
     * for template loading. This is a hook that allows you
     * to custom-configure the configuration object in a subclass.
     * The default implementation returns a new {@link Configuration}
     * instance.
     */
    protected Configuration createConfiguration() {
        return new Configuration();
    }
    
    /**
     * This method is called from {@link #init()} to create the
     * FreeMarker object wrapper object that this servlet will use
     * for adapting request, session, and servlet context attributes into 
     * template models.. This is a hook that allows you
     * to custom-configure the wrapper object in a subclass.
     * The default implementation returns a wrapper that depends on the value
     * of <code>ObjectWrapper</code> init parameter. If <code>simple</code> is
     * specified, {@link ObjectWrapper#SIMPLE_WRAPPER} is used; if <code>jython</code>
     * is specified, {@link freemarker.ext.jython.JythonWrapper} is used. In
     * every other case {@link ObjectWrapper#DEFAULT_WRAPPER} is used.
     */
    protected ObjectWrapper createObjectWrapper() {
        String wrapper = getServletConfig().getInitParameter(DEPR_INITPARAM_OBJECT_WRAPPER);
        if (wrapper != null) { // BC
            if (getInitParameter(Configurable.OBJECT_WRAPPER_KEY) != null) {
                throw new RuntimeException("Conflicting init-params: "
                        + Configurable.OBJECT_WRAPPER_KEY + " and "
                        + DEPR_INITPARAM_OBJECT_WRAPPER);
            }
            if (DEPR_INITPARAM_WRAPPER_BEANS.equals(wrapper)) {
                return ObjectWrapper.BEANS_WRAPPER;
            }
            if(DEPR_INITPARAM_WRAPPER_SIMPLE.equals(wrapper)) {
                return ObjectWrapper.SIMPLE_WRAPPER;
            }
            if(DEPR_INITPARAM_WRAPPER_JYTHON.equals(wrapper)) {
                // Avoiding compile-time dependency on Jython package
                try {
                    return (ObjectWrapper) Class.forName("freemarker.ext.jython.JythonWrapper")
                            .newInstance();
                } catch (InstantiationException e) {
                    throw new InstantiationError(e.getMessage());
                } catch (IllegalAccessException e) {
                    throw new IllegalAccessError(e.getMessage());
                } catch (ClassNotFoundException e) {
                    throw new NoClassDefFoundError(e.getMessage());
                }
            }
//            return BeansWrapper.getDefaultInstance();
            return ObjectWrapper.DEFAULT_WRAPPER;
        } else {
            wrapper = getInitParameter(Configurable.OBJECT_WRAPPER_KEY);
            if (wrapper == null) {
//                return BeansWrapper.getDefaultInstance();
                return ObjectWrapper.DEFAULT_WRAPPER;
            } else {
                try {
                    config.setSetting(Configurable.OBJECT_WRAPPER_KEY, wrapper);
                } catch (TemplateException e) {
                    throw new RuntimeException(e.toString());
                }
                return config.getObjectWrapper();
            }
        }
    }
    
    protected ObjectWrapper getObjectWrapper() {
        return wrapper;
    }
    
    protected final String getTemplatePath() {
        return templatePath;
    }

    protected HttpRequestParametersHashModel createRequestParametersHashModel(HttpServletRequest request) {
        return new HttpRequestParametersHashModel(request);
    }

    /**
     * Called when servlet detects in a request processing that
     * application-global (that is, ServletContext-specific) attributes are not yet
     * set.
     * This is a generic hook you might use in subclasses to perform a specific
     * action on first request in the context. By default it does nothing.
     * @param request the actual HTTP request
     * @param response the actual HTTP response
     */
    protected void initializeServletContext(
        HttpServletRequest request,
        HttpServletResponse response)
            throws ServletException, IOException {
    }

    /**
     * Called when servlet detects in a request processing that session-global 
     * (that is, HttpSession-specific) attributes are not yet set.
     * This is a generic hook you might use in subclasses to perform a specific
     * action on first request in the session. By default it does nothing. It
     * is only invoked on newly created sessions; it is not invoked when a
     * replicated session is reinstantiated in another servlet container.
     * 
     * @param request the actual HTTP request
     * @param response the actual HTTP response
     */
    protected void initializeSession(
        HttpServletRequest request,
        HttpServletResponse response)
        throws ServletException, IOException
    {
    }

    /**
     * Called before the execution is passed to template.process().
     * This is a generic hook you might use in subclasses to perform a specific
     * action before the template is processed. By default does nothing.
     * A typical action to perform here is to inject application-specific
     * objects into the model root
     * @param request the actual HTTP request
     * @param response the actual HTTP response
     * @param template the template that will get executed
     * @param data the data that will be passed to the template
     * @return true to process the template, false to suppress template processing.
     */
    protected boolean preTemplateProcess(
        HttpServletRequest request,
        HttpServletResponse response,
        Template template,
        TemplateModel data)
        throws ServletException, IOException
    {
        return true;
    }

    /**
     * Called after the execution returns from template.process().
     * This is a generic hook you might use in subclasses to perform a specific
     * action after the template is processed. It will be invoked even if the
     * template processing throws an exception. By default does nothing.
     * @param request the actual HTTP request
     * @param response the actual HTTP response
     * @param template the template that was executed
     * @param data the data that was passed to the template
     */
    protected void postTemplateProcess(
        HttpServletRequest request,
        HttpServletResponse response,
        Template template,
        TemplateModel data)
        throws ServletException, IOException
    {
    }
    
    /**
     * Returns the {@link freemarker.template.Configuration} object used by this servlet.
     * Please don't forget that {@link freemarker.template.Configuration} is not thread-safe
     * when you modify it.
     */
    protected Configuration getConfiguration() {
        return config;
    }

    /**
     * If the parameter "nocache" was set to true, generate a set of headers
     * that will advise the HTTP client not to cache the returned page.
     */
    private void setBrowserCachingPolicy(HttpServletResponse res)
    {
        if (nocache)
        {
            // HTTP/1.1 + IE extensions
            res.setHeader("Cache-Control", "no-store, no-cache, must-revalidate, "
                    + "post-check=0, pre-check=0");
            // HTTP/1.0
            res.setHeader("Pragma", "no-cache");
            // Last resort for those that ignore all of the above
            res.setHeader("Expires", EXPIRATION_DATE);
        }
    }
}