Package org.apache.velocity.servlet

Class VelocityServlet

  • All Implemented Interfaces:
    java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig
    public abstract class VelocityServlet
extends javax.servlet.http.HttpServlet
    Deprecated.
    This servlet has been replaced by VelocityViewServlet, available from the Velocity-Tools sub-project. VelocityViewServlet provides support for quick, clean MVC web development. VelocityServlet will be removed in a future version of Velocity.
    Base class which simplifies the use of Velocity with Servlets. Extend this class, implement the handleRequest() method, and add your data to the context. Then call getTemplate("myTemplate.wm"). This class puts some things into the context object that you should be aware of: 
     "req" - The HttpServletRequest object
 "res" - The HttpServletResponse object
    There are other methods you can override to access, alter or control any part of the request processing chain. Please see the javadocs for more information on :
    • loadConfiguration() : for setting up the Velocity runtime
    • createContext() : for creating and loading the Context
    • setContentType() : for changing the content type on a request by request basis
    • handleRequest() : you must implement this
    • mergeTemplate() : the template rendering process
    • requestCleanup() : post rendering resource or other cleanup
    • error() : error handling

    If you put a String with key "contentType" object into the context within either your servlet or within your template, then that will be used to override the default content type specified in the properties file.
    Author:
    Dave Bryson, Jon S. Stevens, Geir Magnusson Jr., Kent Johnson, Daniel Rall $Id: VelocityServlet.java 463298 2006-10-12 16:10:32Z henning $
    See Also:
    Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String CONTENT_TYPE
      Deprecated.
      The HTTP content type context key.
      static java.lang.String DEFAULT_CONTENT_TYPE
      Deprecated.
      The default content type for the response
      static java.lang.String DEFAULT_OUTPUT_ENCODING
      Deprecated.
      Encoding for the output stream
      protected static java.lang.String INIT_PROPS_KEY
      Deprecated.
      This is the string that is looked for when getInitParameter is called (org.apache.velocity.properties).
      static java.lang.String REQUEST
      Deprecated.
      The context key for the HTTP request object.
      static java.lang.String RESPONSE
      Deprecated.
      The context key for the HTTP response object.

    • Constructor Summary

      Constructors 
      Constructor Description
      VelocityServlet()
      Deprecated.
       

    • Method Summary

      All Methods Instance Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      protected java.lang.String chooseCharacterEncoding​(javax.servlet.http.HttpServletRequest request)
      Deprecated.
      Chooses the output character encoding to be used as the value for the "charset=" portion of the HTTP Content-Type header (and thus returned by response.getCharacterEncoding()).
      protected Context createContext​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Deprecated.
      Returns a context suitable to pass to the handleRequest() method

      Default implementation will create a VelocityContext object, put the HttpServletRequest and HttpServletResponse into the context accessable via the keys VelocityServlet.REQUEST and VelocityServlet.RESPONSE, respectively.
      void doGet​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Deprecated.
      Handles HTTP GET requests by calling doRequest(HttpServletRequest, HttpServletResponse).
      void doPost​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Deprecated.
      Handles HTTP POST requests by calling doRequest(HttpServletRequest, HttpServletResponse).
      protected void doRequest​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
      Deprecated.
      Handles all requests (by default).
      protected void error​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.Exception cause)
      Deprecated.
      Invoked when there is an error thrown in any part of doRequest() processing.
      Template getTemplate​(java.lang.String name)
      Deprecated.
      Retrieves the requested template.
      Template getTemplate​(java.lang.String name, java.lang.String encoding)
      Deprecated.
      Retrieves the requested template with the specified character encoding.
      protected Template handleRequest​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, Context ctx)
      Deprecated.
      Implement this method to add your application data to the context, calling the getTemplate() method to produce your return value.
      protected Template handleRequest​(Context ctx)
      Deprecated.
      Use handleRequest( HttpServletRequest request, HttpServletResponse response, Context ctx )
      void init​(javax.servlet.ServletConfig config)
      Deprecated.
      Performs initialization of this servlet.
      protected void initVelocity​(javax.servlet.ServletConfig config)
      Deprecated.
      Initializes the Velocity runtime, first calling loadConfiguration(ServletConvig) to get a java.util.Properties of configuration information and then calling Velocity.init().
      protected java.util.Properties loadConfiguration​(javax.servlet.ServletConfig config)
      Deprecated.
      Use VelocityViewServlet from the Velocity Tools library instead.
      protected void mergeTemplate​(Template template, Context context, javax.servlet.http.HttpServletResponse response)
      Deprecated.
      merges the template with the context.
      protected void requestCleanup​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, Context context)
      Deprecated.
      A cleanup routine which is called at the end of the doRequest(HttpServletRequest, HttpServletResponse) processing sequence, allowing 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)
      Deprecated.
      Sets the content type of the response, defaulting to defaultContentType if not overriden.

      • 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

      • REQUEST

        public static final java.lang.String REQUEST
        Deprecated.
        The context key for the HTTP request object.
        See Also:
        Constant Field Values

      • RESPONSE

        public static final java.lang.String RESPONSE
        Deprecated.
        The context key for the HTTP response object.
        See Also:
        Constant Field Values

      • CONTENT_TYPE

        public static final java.lang.String CONTENT_TYPE
        Deprecated.
        The HTTP content type context key.
        See Also:
        Constant Field Values

      • DEFAULT_CONTENT_TYPE

        public static final java.lang.String DEFAULT_CONTENT_TYPE
        Deprecated.
        The default content type for the response
        See Also:
        Constant Field Values

      • DEFAULT_OUTPUT_ENCODING

        public static final java.lang.String DEFAULT_OUTPUT_ENCODING
        Deprecated.
        Encoding for the output stream
        See Also:
        Constant Field Values

      • INIT_PROPS_KEY

        protected static final java.lang.String INIT_PROPS_KEY
        Deprecated.
        This is the string that is looked for when getInitParameter is called (org.apache.velocity.properties).
        See Also:
        Constant Field Values

    • Constructor Detail

      • VelocityServlet

        public VelocityServlet()
        Deprecated.

    • Method Detail

      • init

        public void init​(javax.servlet.ServletConfig config)
          throws javax.servlet.ServletException
        Deprecated.
        Performs initialization of this servlet. Called by the servlet container on loading.
        Specified by:
        init in interface javax.servlet.Servlet
        Overrides:
        init in class javax.servlet.GenericServlet
        Parameters:
        config - The servlet configuration to apply.
        Throws:
        javax.servlet.ServletException

      • initVelocity

        protected void initVelocity​(javax.servlet.ServletConfig config)
                     throws javax.servlet.ServletException
        Deprecated.
        Initializes the Velocity runtime, first calling loadConfiguration(ServletConvig) to get a java.util.Properties of configuration information and then calling Velocity.init(). Override this to do anything to the environment before the initialization of the singelton takes place, or to initialize the singleton in other ways.
        Parameters:
        config -
        Throws:
        javax.servlet.ServletException

      • loadConfiguration

        protected java.util.Properties loadConfiguration​(javax.servlet.ServletConfig config)
                                          throws java.io.IOException,
                                                 java.io.FileNotFoundException
        Deprecated.
        Use VelocityViewServlet from the Velocity Tools library instead.
        Loads the configuration information and returns that information as a Properties, which will be used to initialize the Velocity runtime.

        Currently, this method gets the initialization parameter VelocityServlet.INIT_PROPS_KEY, which should be a file containing the configuration information.

        To configure your Servlet Spec 2.2 compliant servlet runner to pass this to you, put the following in your WEB-INF/web.xml file 
            <servlet>
      <servlet-name> YourServlet </servlet-name>
      <servlet-class> your.package.YourServlet </servlet-class>
      <init-param>
         <param-name> org.apache.velocity.properties </param-name>
         <param-value> velocity.properties </param-value>
      </init-param>
    </servlet>
        Alternately, if you wish to configure an entire context in this fashion, you may use the following: 
            <context-param>
       <param-name> org.apache.velocity.properties </param-name>
       <param-value> velocity.properties </param-value>
       <description> Path to Velocity configuration </description>
    </context-param>
        Derived classes may do the same, or take advantage of this code to do the loading for them via : 
              Properties p = super.loadConfiguration( config );
        and then add or modify the configuration values from the file.
        Parameters:
        config - ServletConfig passed to the servlets init() function Can be used to access the real path via ServletContext (hint)
        Returns:
        java.util.Properties loaded with configuration values to be used to initialize the Velocity runtime.
        Throws:
        java.io.FileNotFoundException - if a specified file is not found.
        java.io.IOException - I/O problem accessing the specified file, if specified.

      • doGet

        public void doGet​(javax.servlet.http.HttpServletRequest request,
                  javax.servlet.http.HttpServletResponse response)
           throws javax.servlet.ServletException,
                  java.io.IOException
        Deprecated.
        Handles HTTP GET requests by calling doRequest(HttpServletRequest, HttpServletResponse).
        Overrides:
        doGet in class javax.servlet.http.HttpServlet
        Parameters:
        request -
        response -
        Throws:
        javax.servlet.ServletException
        java.io.IOException

      • doPost

        public void doPost​(javax.servlet.http.HttpServletRequest request,
                   javax.servlet.http.HttpServletResponse response)
            throws javax.servlet.ServletException,
                   java.io.IOException
        Deprecated.
        Handles HTTP POST requests by calling doRequest(HttpServletRequest, HttpServletResponse).
        Overrides:
        doPost in class javax.servlet.http.HttpServlet
        Parameters:
        request -
        response -
        Throws:
        javax.servlet.ServletException
        java.io.IOException

      • doRequest

        protected void doRequest​(javax.servlet.http.HttpServletRequest request,
                         javax.servlet.http.HttpServletResponse response)
                  throws javax.servlet.ServletException,
                         java.io.IOException
        Deprecated.
        Handles all requests (by default).
        Parameters:
        request - HttpServletRequest object containing client request
        response - HttpServletResponse object for the response
        Throws:
        javax.servlet.ServletException
        java.io.IOException

      • requestCleanup

        protected void requestCleanup​(javax.servlet.http.HttpServletRequest request,
                              javax.servlet.http.HttpServletResponse response,
                              Context context)
        Deprecated.
        A cleanup routine which is called at the end of the doRequest(HttpServletRequest, HttpServletResponse) processing sequence, allowing a derived class to do resource cleanup or other end of process cycle tasks.
        Parameters:
        request - servlet request from client
        response - servlet reponse
        context - context created by the createContext() method

      • mergeTemplate

        protected void mergeTemplate​(Template template,
                             Context context,
                             javax.servlet.http.HttpServletResponse response)
                      throws ResourceNotFoundException,
                             ParseErrorException,
                             MethodInvocationException,
                             java.io.IOException,
                             java.io.UnsupportedEncodingException,
                             java.lang.Exception
        Deprecated.
        merges the template with the context. Only override this if you really, really really need to. (And don't call us with questions if it breaks :)
        Parameters:
        template - template object returned by the handleRequest() method
        context - context created by the createContext() method
        response - servlet reponse (use this to get the output stream or Writer
        Throws:
        ResourceNotFoundException
        ParseErrorException
        MethodInvocationException
        java.io.IOException
        java.io.UnsupportedEncodingException
        java.lang.Exception

      • setContentType

        protected void setContentType​(javax.servlet.http.HttpServletRequest request,
                              javax.servlet.http.HttpServletResponse response)
        Deprecated.
        Sets the content type of the response, defaulting to defaultContentType if not overriden. Delegates to chooseCharacterEncoding(HttpServletRequest) to select the appropriate character encoding.
        Parameters:
        request - The servlet request from the client.
        response - The servlet reponse to the client.

      • chooseCharacterEncoding

        protected java.lang.String chooseCharacterEncoding​(javax.servlet.http.HttpServletRequest request)
        Deprecated.
        Chooses the output character encoding to be used as the value for the "charset=" portion of the HTTP Content-Type header (and thus returned by response.getCharacterEncoding()). Called by setContentType(HttpServletRequest, HttpServletResponse) if an encoding isn't already specified by Content-Type. By default, chooses the value of RuntimeSingleton's output.encoding property.
        Parameters:
        request - The servlet request from the client.
        Returns:
        The chosen character encoding.

      • createContext

        protected Context createContext​(javax.servlet.http.HttpServletRequest request,
                                javax.servlet.http.HttpServletResponse response)
        Deprecated.
        Returns a context suitable to pass to the handleRequest() method

        Default implementation will create a VelocityContext object, put the HttpServletRequest and HttpServletResponse into the context accessable via the keys VelocityServlet.REQUEST and VelocityServlet.RESPONSE, respectively.
        Parameters:
        request - servlet request from client
        response - servlet reponse to client
        Returns:
        context

      • getTemplate

        public Template getTemplate​(java.lang.String name)
                     throws ResourceNotFoundException,
                            ParseErrorException,
                            java.lang.Exception
        Deprecated.
        Retrieves the requested template.
        Parameters:
        name - The file name of the template to retrieve relative to the template root.
        Returns:
        The requested template.
        Throws:
        ResourceNotFoundException - if template not found from any available source.
        ParseErrorException - if template cannot be parsed due to syntax (or other) error.
        java.lang.Exception - if an error occurs in template initialization

      • getTemplate

        public Template getTemplate​(java.lang.String name,
                            java.lang.String encoding)
                     throws ResourceNotFoundException,
                            ParseErrorException,
                            java.lang.Exception
        Deprecated.
        Retrieves the requested template with the specified character encoding.
        Parameters:
        name - The file name of the template to retrieve relative to the template root.
        encoding - the character encoding of the template
        Returns:
        The requested template.
        Throws:
        ResourceNotFoundException - if template not found from any available source.
        ParseErrorException - if template cannot be parsed due to syntax (or other) error.
        java.lang.Exception - if an error occurs in template initialization
        Since:
        Velocity v1.1

      • handleRequest

        protected Template handleRequest​(javax.servlet.http.HttpServletRequest request,
                                 javax.servlet.http.HttpServletResponse response,
                                 Context ctx)
                          throws java.lang.Exception
        Deprecated.
        Implement this method to add your application data to the context, calling the getTemplate() method to produce your return value.

        In the event of a problem, you may handle the request directly and return null or throw a more meaningful exception for the error handler to catch.
        Parameters:
        request - servlet request from client
        response - servlet reponse
        ctx - The context to add your data to.
        Returns:
        The template to merge with your context or null, indicating that you handled the processing.
        Throws:
        java.lang.Exception
        Since:
        Velocity v1.1

      • handleRequest

        protected Template handleRequest​(Context ctx)
                          throws java.lang.Exception
        Deprecated.
        Use handleRequest( HttpServletRequest request, HttpServletResponse response, Context ctx )
        Implement this method to add your application data to the context, calling the getTemplate() method to produce your return value.

        In the event of a problem, you may simple return null or throw a more meaningful exception.
        Parameters:
        ctx - The context to add your data to.
        Returns:
        The template to merge with your context.
        Throws:
        java.lang.Exception

      • error

        protected void error​(javax.servlet.http.HttpServletRequest request,
                     javax.servlet.http.HttpServletResponse response,
                     java.lang.Exception cause)
              throws javax.servlet.ServletException,
                     java.io.IOException
        Deprecated.
        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.
        cause - Exception that was thrown by some other part of process.
        Throws:
        javax.servlet.ServletException
        java.io.IOException