Package org.apache.velocity.tools.view

Class VelocityViewServlet

  • All Implemented Interfaces:
    java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig
    Direct Known Subclasses:
    VelocityLayoutServlet
    public class VelocityViewServlet
extends javax.servlet.http.HttpServlet

    A servlet to process Velocity templates. This is comparable to the the JspServlet for JSP-based applications.

    The servlet provides the following features:

    • renders Velocity templates
    • provides support for an auto-loaded, configurable toolbox
    • provides transparent access to the servlet request attributes, servlet session attributes and servlet context attributes by auto-searching them
    • logs to the logging facility of the servlet API

    VelocityViewServlet supports the following configuration parameters in web.xml:

    org.apache.velocity.tools
    Path and name of the toolbox configuration file. The path must be relative to the web application root directory. If this parameter is not found, the servlet will check for a toolbox file at '/WEB-INF/tools.xml'.
    org.apache.velocity.properties
    Path and name of the Velocity configuration file. The path must be relative to the web application root directory. If this parameter is not present, Velocity will check for a properties file at '/WEB-INF/velocity.properties'. If no file is found there, then Velocity is initialized with the settings in the classpath at 'org.apache.velocity.tools.view.velocity.properties'.
    org.apache.velocity.tools.shared.config
    By default, this is true. If set to false, then the VelocityView used by this servlet will not be shared with VelocityViewFilters, other VelocityViewServlets or org.apache.velocity.tools.view.jsp.VelocityViewTag's in the application.
    org.apache.velocity.tools.loadDefaults
    By default, this is true. If set to false, then the default toolbox configuration will not be added to your (if any) custom configuration.
    org.apache.velocity.tools.cleanConfiguration
    By default, this is false. If set to true, then then the final toolbox configuration (the combination of any custom one(s) provided by yourself and/or the default configuration(s)) will have all invalid tools, properties, and/or data removed prior to configuring the ToolboxFactory for this servlet by a ConfigurationCleaner
    org.apache.velocity.tools.bufferOutput
    By default, the processed templates are merged directly into the HttpServletResponse's writer. If this parameter is set to true, then the output of the merge process will be buffered before being fed to the response. This allows the error(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.lang.Throwable) method to be overridden to return a "500 Internal Server Error" or at least not return any of the failed request content. Essentially, setting this to true degrades performance in order to enable a more "correct" error response"
    org.apache.velocity.tools.view.class
    Allows to specify a custom class (inheriting from VelocityView) as the View class.
    Version:
    $Id$
    See Also:
    Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String BUFFER_OUTPUT_PARAM  

    • Method Summary

      All Methods Instance Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      protected org.apache.velocity.context.Context createContext​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Get a configured Velocity context for the current request and response
      void doGet​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Handles GET - calls doRequest()
      void doPost​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Handle a POST request - calls doRequest()
      protected void doRequest​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Handles with both GET and POST requests
      protected void error​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.Throwable e)
      Invoked when there is an error thrown in any part of doRequest() processing.
      protected void fillContext​(org.apache.velocity.context.Context context, javax.servlet.http.HttpServletRequest request)
      Standard extension point to populate the context with additional entries
      protected java.lang.String findInitParameter​(javax.servlet.ServletConfig config, java.lang.String key)
      Looks up an init parameter with the specified key in either the ServletConfig or, failing that, in the ServletContext.
      protected org.slf4j.Logger getLog()  
      protected java.io.Writer getOutputWriter​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Get the output stream writer to use.
      protected org.apache.velocity.Template getTemplate​(java.lang.String name)
      Get a template by name
      protected org.apache.velocity.Template getTemplate​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Get a template by client request and response
      protected java.lang.String getVelocityProperty​(java.lang.String name, java.lang.String alternate)  
      protected VelocityView getVelocityView()  
      protected org.apache.velocity.Template handleRequest​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, org.apache.velocity.context.Context ctx)
      This was a common extension point, but now it is usually simpler to override fillContext(org.apache.velocity.context.Context, javax.servlet.http.HttpServletRequest) to add custom things to the Context or override a getTemplate(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) method to change how Templates are retrieved.
      void init​(javax.servlet.ServletConfig config)
      Initializes servlet and VelocityView used to process requests.
      protected void initRequest​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Request and response initialization.
      protected void manageResourceNotFound​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, org.apache.velocity.exception.ResourceNotFoundException e)
      Manages the ResourceNotFoundException to send an HTTP 404 result when needed.
      protected void mergeTemplate​(org.apache.velocity.Template template, org.apache.velocity.context.Context context, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Merge template
      protected void mergeTemplate​(org.apache.velocity.Template template, org.apache.velocity.context.Context context, javax.servlet.http.HttpServletResponse response)
      Deprecated.
      see {mergeTemplate(Template, Context, HttpServletRequest, HttpServletResponse)}
      protected void requestCleanup​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, org.apache.velocity.context.Context context)
      Cleanup routine called at the end of the request processing sequence allows a derived class to do resource cleanup or other end of process cycle tasks.
      protected void setContentType​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Sets the content type of the response.
      protected void setVelocityView​(VelocityView view)  

      • Methods inherited from class javax.servlet.http.HttpServlet

        doDelete, doHead, doOptions, doPut, doTrace, getLastModified, service, service

      • Methods inherited from class javax.servlet.GenericServlet

        destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • BUFFER_OUTPUT_PARAM

        public static final java.lang.String BUFFER_OUTPUT_PARAM
        See Also:
        Constant Field Values

    • Constructor Detail

      • VelocityViewServlet

        public VelocityViewServlet()

    • Method Detail

      • init

        public void init​(javax.servlet.ServletConfig config)
          throws javax.servlet.ServletException

        Initializes servlet and VelocityView used to process requests. Called by the servlet container on loading.

        Specified by:
        init in interface javax.servlet.Servlet
        Overrides:
        init in class javax.servlet.GenericServlet
        Parameters:
        config - servlet configuation
        Throws:
        javax.servlet.ServletException

      • findInitParameter

        protected java.lang.String findInitParameter​(javax.servlet.ServletConfig config,
                                             java.lang.String key)
        Looks up an init parameter with the specified key in either the ServletConfig or, failing that, in the ServletContext.
        Parameters:
        config - servlet config
        key - parameter key
        Returns:
        parameter value or null

      • getVelocityView

        protected VelocityView getVelocityView()

      • setVelocityView

        protected void setVelocityView​(VelocityView view)

      • getVelocityProperty

        protected java.lang.String getVelocityProperty​(java.lang.String name,
                                               java.lang.String alternate)

      • getLog

        protected org.slf4j.Logger getLog()

      • doGet

        public void doGet​(javax.servlet.http.HttpServletRequest request,
                  javax.servlet.http.HttpServletResponse response)
           throws javax.servlet.ServletException,
                  java.io.IOException
        Handles GET - calls doRequest()
        Overrides:
        doGet in class javax.servlet.http.HttpServlet
        Parameters:
        request - servlet request
        response - servlet response
        Throws:
        javax.servlet.ServletException - from underlying call
        java.io.IOException - from underlying call

      • doPost

        public void doPost​(javax.servlet.http.HttpServletRequest request,
                   javax.servlet.http.HttpServletResponse response)
            throws javax.servlet.ServletException,
                   java.io.IOException
        Handle a POST request - calls doRequest()
        Overrides:
        doPost in class javax.servlet.http.HttpServlet
        Parameters:
        request - servlet request
        response - servlet response
        Throws:
        javax.servlet.ServletException - from underlying call
        java.io.IOException - from underlying call

      • doRequest

        protected void doRequest​(javax.servlet.http.HttpServletRequest request,
                         javax.servlet.http.HttpServletResponse response)
                  throws java.io.IOException
        Handles with both GET and POST requests
        Parameters:
        request - HttpServletRequest object containing client request
        response - HttpServletResponse object for the response
        Throws:
        java.io.IOException - from underlying processing

      • initRequest

        protected void initRequest​(javax.servlet.http.HttpServletRequest request,
                           javax.servlet.http.HttpServletResponse response)
                    throws java.io.IOException

        Request and response initialization. Default version does only one thing: set request POST parameters encoding to Velocity input encoding.

        Parameters:
        request - HttpServletRequest object containing client request
        response - HttpServletResponse object for the response
        Throws:
        java.io.IOException - if thrown by underlying handling

      • createContext

        protected org.apache.velocity.context.Context createContext​(javax.servlet.http.HttpServletRequest request,
                                                            javax.servlet.http.HttpServletResponse response)
        Get a configured Velocity context for the current request and response
        Parameters:
        request - client request
        response - client response
        Returns:
        configured context

      • fillContext

        protected void fillContext​(org.apache.velocity.context.Context context,
                           javax.servlet.http.HttpServletRequest request)
        Standard extension point to populate the context with additional entries
        Parameters:
        context - target context
        request - client request

      • setContentType

        protected void setContentType​(javax.servlet.http.HttpServletRequest request,
                              javax.servlet.http.HttpServletResponse response)
        Sets the content type of the response. This is available to be overriden by a derived class.

        The default implementation is : response.setContentType(getVelocityView().getDefaultContentType()); where defaultContentType is set to the value of the default.contentType property, or "text/html" if that was not set for the VelocityView.

        Parameters:
        request - servlet request from client
        response - servlet reponse to client

      • getTemplate

        protected org.apache.velocity.Template getTemplate​(javax.servlet.http.HttpServletRequest request,
                                                   javax.servlet.http.HttpServletResponse response)
        Get a template by client request and response
        Parameters:
        request - client request
        response - client response
        Returns:
        found template

      • getTemplate

        protected org.apache.velocity.Template getTemplate​(java.lang.String name)
        Get a template by name
        Parameters:
        name - template name
        Returns:
        found template

      • mergeTemplate

        protected void mergeTemplate​(org.apache.velocity.Template template,
                             org.apache.velocity.context.Context context,
                             javax.servlet.http.HttpServletRequest request,
                             javax.servlet.http.HttpServletResponse response)
                      throws java.io.IOException
        Merge template
        Parameters:
        template - input template
        context - Velocity context
        request - client request
        response - client response
        Throws:
        java.io.IOException

      • getOutputWriter

        protected java.io.Writer getOutputWriter​(javax.servlet.http.HttpServletRequest request,
                                         javax.servlet.http.HttpServletResponse response)
                                  throws java.io.IOException
        Get the output stream writer to use. If the writer is to be written afterwards to the response writer (as when org.apache.velocity.tools.bufferOutput is true), this method must set the org.apache.velocity.tools.bufferOutput request attribute to true.
        Parameters:
        request -
        response -
        Returns:
        Throws:
        java.io.IOException

      • mergeTemplate

        @Deprecated
protected void mergeTemplate​(org.apache.velocity.Template template,
                             org.apache.velocity.context.Context context,
                             javax.servlet.http.HttpServletResponse response)
                      throws java.io.IOException
        Deprecated.
        see {mergeTemplate(Template, Context, HttpServletRequest, HttpServletResponse)}
        Merge template
        Parameters:
        template - target template
        context - client request
        response - client response
        Throws:
        java.io.IOException

      • error

        protected void error​(javax.servlet.http.HttpServletRequest request,
                     javax.servlet.http.HttpServletResponse response,
                     java.lang.Throwable e)
        Invoked when there is an error thrown in any part of doRequest() processing.

        Default will send a simple HTML response indicating there was a problem.
        Parameters:
        request - original HttpServletRequest from servlet container.
        response - HttpServletResponse object from servlet container.
        e - Exception that was thrown by some other part of process.

      • manageResourceNotFound

        protected void manageResourceNotFound​(javax.servlet.http.HttpServletRequest request,
                                      javax.servlet.http.HttpServletResponse response,
                                      org.apache.velocity.exception.ResourceNotFoundException e)
                               throws java.io.IOException
        Manages the ResourceNotFoundException to send an HTTP 404 result when needed.
        Parameters:
        request - The request object.
        response - The response object.
        e - The exception to check.
        Throws:
        java.io.IOException - If something goes wrong when sending the HTTP error.

      • requestCleanup

        protected void requestCleanup​(javax.servlet.http.HttpServletRequest request,
                              javax.servlet.http.HttpServletResponse response,
                              org.apache.velocity.context.Context context)
        Cleanup routine called at the end of the request processing sequence allows a derived class to do resource cleanup or other end of process cycle tasks. This default implementation does nothing.
        Parameters:
        request - servlet request from client
        response - servlet response
        context - Context that was merged with the requested template