Package freemarker.ext.servlet

Class FreemarkerServlet

java.lang.Object
javax.servlet.GenericServlet
javax.servlet.http.HttpServlet
freemarker.ext.servlet.FreemarkerServlet
All Implemented Interfaces:
Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig
public class FreemarkerServlet extends javax.servlet.http.HttpServlet
FreeMarker MVC View servlet that can be used similarly to JSP views. That is, you put the variables to expose into HTTP servlet request attributes, then forward to an FTL file (instead of to a JSP file) that's mapped to this servet (usually via the <url-pattern>*.ftl<url-pattern>). See web.xml example (and more) in the FreeMarker Manual!

Note that this is for the legacy "javax" Servlet/JSP API; for Jakarta (that is, in modern Servlet containers), use freemarker.ext.jakarta.servlet.FreemarkerServlet instead (since 2.3.33).

Main features

  • It makes all request, request parameters, session, and servlet context attributes available to templates through Request, RequestParameters, Session, and Application variables.
  • The scope variables are also available via automatic scope discovery. That is, writing Application.attrName, Session.attrName, Request.attrName is not mandatory; it's enough to write attrName, and if no such variable was created in the template, it will search the variable in Request, and then in Session, and finally in Application.
  • It creates a variable with name JspTaglibs that can be used to load JSP taglibs. For example:
    <#assign dt=JspTaglibs["http://displaytag.sf.net"]> or <#assign tiles=JspTaglibs["/WEB-INF/struts-tiles.tld"]>.
  • A custom directive named include_page allows you to include the output of another servlet resource from your servlet container, just as if you used ServletRequest.getRequestDispatcher(path).include(): <@include_page path="/myWebapp/somePage.jsp"/>. You can also pass parameters to the newly included page by passing a hash named params: <@include_page path="/myWebapp/somePage.jsp" params= lang: "en", q="5"}/>. By default, the request parameters of the original request (the one being processed by FreemarkerServlet) are also inherited by the include. You can explicitly control this inheritance using the inherit_params parameter: <@include_page path="/myWebapp/somePage.jsp" params={lang: "en", q="5"} inherit_params=false/>.

Supported init-param-s

  • "TemplatePath": Specifies the location of the template files. By default, this is interpreted as a ServletContext resource path, which practically means a web application directory relative path, or a WEB-INF/lib/*.jar/META-INF/resources-relative path (note that this last haven't always worked before FreeMarker 2.3.23).
    Alternatively, you can prepend it with file:// to indicate a literal path in the file system (i.e. file:///var/www/project/templates/). Note that three slashes were used to specify an absolute path.
    Also, you can prepend it with classpath:, like in classpath:com/example/templates, to indicate that you want to load templates from the specified package accessible through the Thread Context Class Loader of the thread that initializes this servlet.
    If incompatible_improvements is set to 2.3.22 (or higher), you can specify multiple comma separated locations inside square brackets, like: [ WEB-INF/templates, classpath:com/example/myapp/templates ]. This internally creates a MultiTemplateLoader. Note again that if incompatible_improvements isn't set to at least 2.3.22, the initial [ has no special meaning, and so this feature is unavailable.
    Any of the above can have a ?setting(name=value, ...) postfix to set the JavaBeans properties of the TemplateLoader created. For example, /templates?settings(attemptFileAccess=false, URLConnectionUsesCaches=true) calls WebappTemplateLoader.setAttemptFileAccess(boolean) and WebappTemplateLoader.setURLConnectionUsesCaches(Boolean) to tune the WebappTemplateLoader. For backward compatibility (not recommended!), you can use the class:// prefix, like in class://com/example/templates format, which is similar to classpath:, except that it uses the defining class loader of this servlet's class. This can cause template-not-found errors, if that class (in freemarer.jar usually) is not local to the web application, while the templates are.
    The default value is class:// (that is, the root of the class hierarchy), which is not recommended anymore, and should be overwritten with the "TemplatePath" init-param.
  • "NoCache": If set to true, generates headers in the response that advise the HTTP client not to cache the returned page. If false, the HTTP response is not modified for this purpose. The default is false.
  • "ContentType": The Content-type HTTP header value used in the HTTP responses when nothing else specifies the MIME type. The things that may specify the MIME type (and hence this init-param is ignored), starting with the highest precedence, are:
    1. If the "OverrideResponseContentType" init-param is "never" (the default is "always"), then the value of ServletResponse.getContentType() is used if that's non-null.
    2. The template's content_type custom attribute, usually specified via the attributes parameter of the <#ftl> directive. This is a legacy feature, deprecated by the OutputFormat mechanism.
    3. The output format of the template, if that has non-null MIME-type (OutputFormat.getMimeType()). When a template has no output format specified, UndefinedOutputFormat is used, which has null MIME-type. (The output format of a template is deduced from Configuration settings, or can be specified directly in the template, like <#ftl outputFormat="HTML">. See the FreeMarker Manual for more about the output format mechanism. Note that setting an output format may turns on auto-escaping, so it's not just about MIME types.)
    4. If the "OverrideResponseContentType" init-param is not "always" (the default is "always"), then the value of ServletResponse.getContentType() is used if that's non-null.
    If none of the above gives a MIME type, then this init-param does. Defaults to "text/html". If and only if the "ResponseCharacterEncoding" init-param is set to "legacy" (which is the default of it), the content type may include the charset (as in "text/html; charset=utf-8"), in which case that specifies the actual charset of the output. If the the "ResponseCharacterEncoding" init-param is not set to "legacy", then specifying the charset in the "ContentType" init-param is not allowed, and will cause servlet initialization error.
  • "OverrideResponseContentType" (since 2.3.24): Specifies when we should override the contentType that might be already set (i.e., non-null) in the HttpServletResponse. The default is "always", which means that we always set the content type. Another possible value is "never", which means that we don't set the content type in the response, unless ServletResponse.getContentType() is null. The third possible value is "whenTemplateHasMimeType", which means that we only set the content type if either the template has an associated OutputFormat with non-null OutputFormat.getMimeType(), or it has a custom attribute with name content_type, or ServletResponse.getContentType() is null. Setting this init-param allows you to specify the content type before forwarding to FreemarkerServlet.
  • "OverrideResponseLocale" (since 2.3.24): Specifies if we should override the template locale that might be already set (i.e., non-null) in the HttpServletRequest. The default is "always", which means that we always deduce the template locale by invoking deduceLocale(String, HttpServletRequest, HttpServletResponse). Another possible value is "never", which means that we don't deduce the template locale, unless ServletRequest.getLocale() is null.
  • "ResponseCharacterEncoding" (since 2.3.24): Specifies how the HttpServletResponse "character encoding" (as in ServletResponse.setCharacterEncoding(String)) will be deduced. The possible modes are:
    • "legacy": This is the default for backward compatibility; in new applications, use "fromTemplate" (or some of the other options) instead. "legacy" will use the charset of the template file to set the charset of the servlet response. Except, if the "ContentType" init-param contains a charset, it will use that instead. A quirk of this legacy mode is that it's not aware of the Configurable.getOutputEncoding() FreeMarker setting, and thus never reads or writes it (though very few applications utilize that setting anyway). Also, it sets the charset of the servlet response by adding it to the response content type via calling ServletResponse.setContentType(String) (as that was the only way before Servlet 2.4), not via the more modern ServletResponse.setCharacterEncoding(String) method. Note that the charset of a template usually comes from Configuration.getDefaultEncoding() (i.e., from the default_encoding FreeMarker setting), occasionally from Configuration.getEncoding(Locale) (when FreeMarker was configured to use different charsets depending on the locale) or even more rarely from Configuration.getTemplateConfigurations() (when FreeMarker was configured to use a specific charset for certain templates).
    • "fromTemplate": This should be used in most applications, but it's not the default for backward compatibility. It reads the Configurable.getOutputEncoding() setting of the template (note that the template usually just inherits that from the Configuration), and if that's not set, then reads the source charset of the template, just like "legacy". Then it passes the charset acquired this way to ServletResponse.setCharacterEncoding(String) and Environment.setOutputEncoding(String). (It doesn't call the legacy ServletResponse.setContentType(String) API to set the charset.) (Note that if the template has a content_type template attribute (which is deprecated) that specifies a charset, it will be used as the output charset of that template.)
    • "doNotSet": FreemarkerServlet will not set the HttpServletResponse "character encoding". It will still call Environment.setOutputEncoding(String), so that the running template will be aware of the charset used for the output.
    • "force " + charset name, for example force UTF-8: The output charset will be the one specified after "force" + space, regardless of everything. The charset specified this way is passed to ServletResponse.setCharacterEncoding(String) and Environment.setOutputEncoding(String). If the charset name is not recognized by Java, the servlet initialization will fail.
  • "BufferSize": Sets the size of the output buffer in bytes, or if "KB" or "MB" is written after the number (like <param-value>256 KB</param-value>) then in kilobytes or megabytes. This corresponds to ServletResponse.setBufferSize(int). If the HttpServletResponse state doesn't allow changing the buffer size, it will silently do nothing. If this init param isn't specified, then the buffer size is not set by FreemarkerServlet in the HTTP response, which usually means that the default buffer size of the servlet container will be used.
  • "ExceptionOnMissingTemplate" (since 2.3.22): If false (default, but not recommended), if a template is requested that's missing, this servlet responses with a HTTP 404 "Not found" error, and only logs the problem with debug level. If true (recommended), the servlet will log the issue with error level, then throws an exception that bubbles up to the servlet container, which usually then creates a HTTP 500 "Internal server error" response (and maybe logs the event into the container log). See "Error handling" later for more!
  • "MetaInfTldSources" (since 2.3.22): Comma separated list of items, each is either "webInfPerLibJars", or "classpath" optionally followed by colon and a regular expression, or "clear". For example <param-value>classpath:.*myoverride.*\.jar$, webInfPerLibJars, classpath:.*taglib.*\.jar$</param-value>, or <param-value>classpath</param-value>. (Whitespace around the commas and list items will be ignored.) See TaglibFactory.setMetaInfTldSources(List) for more information. Defaults to a list that contains "webInfPerLibJars" only (can be overridden with createDefaultMetaInfTldSources()). Note that this can be also specified with the "org.freemarker.jsp.metaInfTldSources" system property. If both the init-param and the system property exists, the sources listed in the system property will be added after those specified by the init-param. This is where the special entry, "clear" comes handy, as it will remove all previous list items. (An intended usage of the system property is setting it to clear, classpath in the Eclipse run configuration if you are running the application without putting the dependency jar-s into WEB-INF/lib.) Also, note that further classpath:<pattern> items are added automatically at the end of this list based on Jetty's "org.eclipse.jetty.server.webapp.ContainerIncludeJarPattern" servlet context attribute.
  • "ClasspathTlds" (since 2.3.22): Comma separated list of paths; see TaglibFactory.setClasspathTlds(List). Whitespace around the list items will be ignored. Defaults to no paths (can be overidden with createDefaultClassPathTlds()). Note that this can also be specified with the "org.freemarker.jsp.classpathTlds" system property. If both the init-param and the system property exists, the items listed in system property will be added after those specified by the init-param.
  • "Debug": Deprecated, has no effect since 2.3.22. (Earlier it has enabled/disabled sending debug-level log messages to the servlet container log, but this servlet doesn't log debug level messages into the servlet container log anymore, only into the FreeMarker log.)
  • The following init-params are supported only for backward compatibility, and their usage is discouraged: TemplateUpdateInterval, DefaultEncoding, ObjectWrapper, TemplateExceptionHandler. Instead, use init-params with the setting names documented at Configuration.setSetting(String, String), such as object_wrapper.
  • Any other init-params will be interpreted as Configuration-level FreeMarker setting. See the possible names and values at Configuration.setSetting(String, String). Note that these init-param names are starting with lower-case letter (upper-case init-params are used for FreemarkerSerlvet settings).

Error handling

Notes:

  • Logging below, where not said otherwise, always refers to logging with FreeMarker's logging facility (see Logger), under the "freemarker.servlet" category.
  • Throwing a ServletException to the servlet container is mentioned at a few places below. That in practice usually means HTTP 500 "Internal server error" response, and maybe a log entry in the servlet container's log.

Errors types:

  • If the servlet initialization fails, the servlet won't be started as usual. The cause is usually logged with error level. When it isn't, check the servlet container's log.
  • If the requested template doesn't exist, by default the servlet returns a HTTP 404 "Not found" response, and logs the problem with debug level. Responding with HTTP 404 is how JSP behaves, but it's actually not a recommended setting anymore. By setting "ExceptionOnMissingTemplate" init-param to true (recommended), it will instead log the problem with error level, then the servlet throws ServletException to the servlet container (with the proper cause exception). After all, if the visited URL had an associated "action" but the template behind it is missing, that's an internal server error, not a wrong URL.
  • If the template contains parsing errors, it will log it with error level, then the servlet throws ServletException to the servlet container (with the proper cause exception).
  • If the template throws exception during its execution, and the value of the template_exception_handler init-param is rethrow (recommended), it will log it with error level and then the servlet throws ServletException to the servlet container (with the proper cause exception). But beware, the default value of the template_exception_handler init-param is html_debug, which is for development only! Set it to rethrow for production. The html_debug (and debug) handlers will print error details to the page and then commit the HTTP response with response code 200 "OK", thus, the server wont be able roll back the response and send back an HTTP 500 page. This is so that the template developers will see the error without digging the logs.
See Also:
Serialized Form

  • Field Details

    • serialVersionUID

      public static final long serialVersionUID
      See Also:
      Constant Field Values

    • INIT_PARAM_TEMPLATE_PATH

      public static final String INIT_PARAM_TEMPLATE_PATH
      Init-param name - see the FreemarkerServlet class documentation about the init-params. (This init-param has existed long before 2.3.22, but this constant was only added then.)
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • INIT_PARAM_NO_CACHE

      public static final String INIT_PARAM_NO_CACHE
      Init-param name - see the FreemarkerServlet class documentation about the init-params. (This init-param has existed long before 2.3.22, but this constant was only added then.)
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • INIT_PARAM_CONTENT_TYPE

      public static final String INIT_PARAM_CONTENT_TYPE
      Init-param name - see the FreemarkerServlet class documentation about the init-params. (This init-param has existed long before 2.3.22, but this constant was only added then.)
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • INIT_PARAM_OVERRIDE_RESPONSE_CONTENT_TYPE

      public static final String INIT_PARAM_OVERRIDE_RESPONSE_CONTENT_TYPE
      Init-param name - see the FreemarkerServlet class documentation about the init-params.
      Since:
      2.3.24
      See Also:
      Constant Field Values

    • INIT_PARAM_RESPONSE_CHARACTER_ENCODING

      public static final String INIT_PARAM_RESPONSE_CHARACTER_ENCODING
      Init-param name - see the FreemarkerServlet class documentation about the init-params.
      Since:
      2.3.24
      See Also:
      Constant Field Values

    • INIT_PARAM_OVERRIDE_RESPONSE_LOCALE

      public static final String INIT_PARAM_OVERRIDE_RESPONSE_LOCALE
      Init-param name - see the FreemarkerServlet class documentation about the init-params.
      Since:
      2.3.24
      See Also:
      Constant Field Values

    • INIT_PARAM_BUFFER_SIZE

      public static final String INIT_PARAM_BUFFER_SIZE
      Init-param name - see the FreemarkerServlet class documentation about the init-params.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • INIT_PARAM_META_INF_TLD_LOCATIONS

      public static final String INIT_PARAM_META_INF_TLD_LOCATIONS
      Init-param name - see the FreemarkerServlet class documentation about the init-params.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • INIT_PARAM_EXCEPTION_ON_MISSING_TEMPLATE

      public static final String INIT_PARAM_EXCEPTION_ON_MISSING_TEMPLATE
      Init-param name - see the FreemarkerServlet class documentation about the init-params.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • INIT_PARAM_CLASSPATH_TLDS

      public static final String INIT_PARAM_CLASSPATH_TLDS
      Init-param name - see the FreemarkerServlet class documentation about the init-params.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • INIT_PARAM_VALUE_NEVER

      public static final String INIT_PARAM_VALUE_NEVER
      See Also:
      Constant Field Values

    • INIT_PARAM_VALUE_ALWAYS

      public static final String INIT_PARAM_VALUE_ALWAYS
      See Also:
      Constant Field Values

    • INIT_PARAM_VALUE_WHEN_TEMPLATE_HAS_MIME_TYPE

      public static final String INIT_PARAM_VALUE_WHEN_TEMPLATE_HAS_MIME_TYPE
      See Also:
      Constant Field Values

    • INIT_PARAM_VALUE_FROM_TEMPLATE

      public static final String INIT_PARAM_VALUE_FROM_TEMPLATE
      See Also:
      Constant Field Values

    • INIT_PARAM_VALUE_LEGACY

      public static final String INIT_PARAM_VALUE_LEGACY
      See Also:
      Constant Field Values

    • INIT_PARAM_VALUE_DO_NOT_SET

      public static final String INIT_PARAM_VALUE_DO_NOT_SET
      See Also:
      Constant Field Values

    • INIT_PARAM_VALUE_FORCE_PREFIX

      public static final String INIT_PARAM_VALUE_FORCE_PREFIX
      See Also:
      Constant Field Values

    • SYSTEM_PROPERTY_META_INF_TLD_SOURCES

      public static final String SYSTEM_PROPERTY_META_INF_TLD_SOURCES
      When set, the items defined in it will be added after those coming from the "MetaInfTldSources" init-param. The value syntax is the same as of the init-param. Note that "clear" can be used to re-start the list, rather than continue it.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • SYSTEM_PROPERTY_CLASSPATH_TLDS

      public static final String SYSTEM_PROPERTY_CLASSPATH_TLDS
      When set, the items defined in it will be added after those coming from the "ClasspathTlds" init-param. The value syntax is the same as of the init-param.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • META_INF_TLD_LOCATION_WEB_INF_PER_LIB_JARS

      public static final String META_INF_TLD_LOCATION_WEB_INF_PER_LIB_JARS
      Used as part of the value of the "MetaInfTldSources" init-param.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • META_INF_TLD_LOCATION_CLASSPATH

      public static final String META_INF_TLD_LOCATION_CLASSPATH
      Used as part of the value of the "MetaInfTldSources" init-param.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • META_INF_TLD_LOCATION_CLEAR

      public static final String META_INF_TLD_LOCATION_CLEAR
      Used as part of the value of the "MetaInfTldSources" init-param.
      Since:
      2.3.22
      See Also:
      Constant Field Values

    • KEY_REQUEST

      public static final String KEY_REQUEST
      See Also:
      Constant Field Values

    • KEY_INCLUDE

      public static final String KEY_INCLUDE
      See Also:
      Constant Field Values

    • KEY_REQUEST_PRIVATE

      public static final String KEY_REQUEST_PRIVATE
      See Also:
      Constant Field Values

    • KEY_REQUEST_PARAMETERS

      public static final String KEY_REQUEST_PARAMETERS
      See Also:
      Constant Field Values

    • KEY_SESSION

      public static final String KEY_SESSION
      See Also:
      Constant Field Values

    • KEY_APPLICATION

      public static final String KEY_APPLICATION
      See Also:
      Constant Field Values

    • KEY_APPLICATION_PRIVATE

      public static final String KEY_APPLICATION_PRIVATE
      See Also:
      Constant Field Values

    • KEY_JSP_TAGLIBS

      public static final String KEY_JSP_TAGLIBS
      See Also:
      Constant Field Values

    • debug

      @Deprecated protected boolean debug
      Deprecated.
      Not used anymore; to enable/disable debug logging, just set the logging level of the logging library used by Logger.

  • Constructor Details

    • FreemarkerServlet

      public FreemarkerServlet()

  • Method Details

    • init

      public void init() throws javax.servlet.ServletException
      Don't override this method to adjust FreeMarker settings! Override the protected methods for that, such as createConfiguration(), createTemplateLoader(String), createDefaultObjectWrapper(), etc. Also note that lot of things can be changed with init-params instead of overriding methods, so if you override settings, usually you should only override their defaults.
      Overrides:
      init in class javax.servlet.GenericServlet
      Throws:
      javax.servlet.ServletException

    • createTemplateLoader

      protected TemplateLoader createTemplateLoader​(String templatePath) throws IOException
      Create the template loader. The default implementation will create a ClassTemplateLoader if the template path starts with "class://", a FileTemplateLoader if the template path starts with "file://", and a WebappTemplateLoader otherwise. Also, if incompatible_improvements is 2.3.22 or higher, it will create a MultiTemplateLoader if the template path starts with "[".
      Parameters:
      templatePath - the template path to create a loader for
      Returns:
      a newly created template loader
      Throws:
      IOException

    • doGet

      public void doGet​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException
      Overrides:
      doGet in class javax.servlet.http.HttpServlet
      Throws:
      javax.servlet.ServletException
      IOException

    • doPost

      public void doPost​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException
      Overrides:
      doPost in class javax.servlet.http.HttpServlet
      Throws:
      javax.servlet.ServletException
      IOException

    • processEnvironment

      protected void processEnvironment​(Environment env, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws TemplateException, IOException
      This is the method that actually executes the template. The original implementation coming from FreemarkerServlet simply calls Environment.process(). Overriding this method allows you to prepare the Environment before the execution, or extract information from the Environment after the execution. It also allows you to capture exceptions throw by the template.
      Parameters:
      env - The Environment object already set up to execute the template. You only have to call Environment.process() and the output will be produced by the template.
      Throws:
      TemplateException
      IOException
      Since:
      2.3.24

    • deduceLocale

      protected Locale deduceLocale​(String templatePath, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException
      Returns the locale used for the Configuration.getTemplate(String, Locale) call (as far as the "OverrideResponseLocale" Servlet init-param allows that). The base implementation in FreemarkerServlet simply returns the locale setting of the configuration. Override this method to provide different behavior, for example, to use the locale indicated in the HTTP request.
      Parameters:
      templatePath - The template path (template name) as it will be passed to Configuration.getTemplate(String). (Not to be confused with the servlet init-param of identical name; they aren't related.)
      Throws:
      javax.servlet.ServletException - Can be thrown since 2.3.22, if the locale can't be deduced from the URL.

    • createModel

      protected TemplateModel createModel​(ObjectWrapper objectWrapper, javax.servlet.ServletContext servletContext, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws TemplateModelException
      Throws:
      TemplateModelException

    • createTaglibFactory

      protected TaglibFactory createTaglibFactory​(ObjectWrapper objectWrapper, javax.servlet.ServletContext servletContext) throws TemplateModelException
      Called to create the TaglibFactory once per servlet context. The default implementation configures it based on the servlet-init parameters and various other environmental settings, so if you override this method, you should call super, then adjust the result.
      Throws:
      TemplateModelException
      Since:
      2.3.22

    • createDefaultClassPathTlds

      protected List createDefaultClassPathTlds()
      Creates the default of the "ClasspathTlds" init-param; if this init-param is specified, it will be appended after the default, not replace it.

      The implementation in FreemarkerServlet returns TaglibFactory.DEFAULT_CLASSPATH_TLDS.

      Returns:
      A List of String-s; not null.
      Since:
      2.3.22

    • createDefaultMetaInfTldSources

      protected List createDefaultMetaInfTldSources()
      Creates the default of the "MetaInfTldSources" init-param; if this init-param is specified, it will completelly replace the default value.

      The implementation in FreemarkerServlet returns TaglibFactory.DEFAULT_META_INF_TLD_SOURCES.

      Returns:
      A List of TaglibFactory.MetaInfTldSource-s; not null.
      Since:
      2.3.22

    • requestUrlToTemplatePath

      protected String requestUrlToTemplatePath​(javax.servlet.http.HttpServletRequest request) throws javax.servlet.ServletException
      Maps the request URL to a template path (template name) that is passed to 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.
      Parameters:
      request - The currently processed HTTP request
      Returns:
      The template path (template name); can't be null. This is what's passed to Configuration.getTemplate(String) later. (Not to be confused with the templatePath servlet init-param of identical name; that basically specifies the "virtual file system" to which this will be relative to.)
      Throws:
      javax.servlet.ServletException - Can be thrown since 2.3.22, if the template path can't be deduced from the URL.

    • preprocessRequest

      protected boolean preprocessRequest​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException
      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.
      Parameters:
      request - the HTTP request
      response - the HTTP response
      Returns:
      true to indicate this method has processed the request entirely, and that the further request processing should not take place.
      Throws:
      javax.servlet.ServletException
      IOException

    • createConfiguration

      protected Configuration createConfiguration()
      Creates the FreeMarker Configuration singleton and (when overidden) maybe sets its defaults. Servlet init-params will be applied later, and thus can overwrite the settings specified here.

      By overriding this method you can set your preferred Configuration setting defaults, as only the settings for which an init-param was specified will be overwritten later. (Note that FreemarkerServlet also has its own defaults for a few settings, but since 2.3.22, the servlet detects if those settings were already set here and then it won't overwrite them.)

      The default implementation simply creates a new instance with Configuration() and returns it.

    • setConfigurationDefaults

      protected void setConfigurationDefaults()
      Sets the defaults of the configuration that are specific to the FreemarkerServlet subclass. This is called after the common (wired in) FreemarkerServlet setting defaults was set, also the

    • createObjectWrapper

      protected ObjectWrapper createObjectWrapper()
      Called from init() to create the ObjectWrapper; to customzie this aspect, in most cases you should override createDefaultObjectWrapper() instead. Overriding this method is necessary when you want to customize how the ObjectWrapper is created from the init-param values, or you want to do some post-processing (like checking) on the created ObjectWrapper. To customize init-param interpretation, call GenericServlet.getInitParameter(String) with Configurable.OBJECT_WRAPPER_KEY as argument, and see if it returns a value that you want to interpret yourself. If was null or you don't want to interpret the value, fall back to the super method.

      The default implementation interprets the object_wrapper servlet init-param with calling Configurable.setSetting(String, String) (see valid values there), or if there's no such servlet init-param, then it calls createDefaultObjectWrapper().

      Returns:
      The ObjectWrapper that will be used for adapting request, session, and servlet context attributes to TemplateModel-s, and also as the object wrapper setting of Configuration.

    • createDefaultObjectWrapper

      protected ObjectWrapper createDefaultObjectWrapper()
      Override this to specify what the default ObjectWrapper will be when the object_wrapper Servlet init-param wasn't specified. Note that this is called by createConfiguration(), and so if that was also overidden but improperly then this method might won't be ever called. Also note that if you set the object_wrapper in createConfiguration(), then this won't be called, since then that has already specified the default.

      The default implementation calls Configuration.getDefaultObjectWrapper(freemarker.template.Version). You should also pass in the version paramter when creating an ObjectWrapper that supports that. You can get the version by calling getConfiguration() and then Configuration.getIncompatibleImprovements().

      Since:
      2.3.22

    • getObjectWrapper

      protected ObjectWrapper getObjectWrapper()
      Should be final; don't override it. Override createObjectWrapper() instead.

    • getTemplatePath

      @Deprecated protected final String getTemplatePath()
      Deprecated.
      Not called by FreeMarker code, and there's no point to override this (unless to cause confusion).
      The value of the TemplatePath init-param. null if the template_loader setting was set in a custom createConfiguration().

    • createRequestParametersHashModel

      protected HttpRequestParametersHashModel createRequestParametersHashModel​(javax.servlet.http.HttpServletRequest request)

    • initializeServletContext

      protected void initializeServletContext​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.ServletException, IOException
      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.
      Parameters:
      request - the actual HTTP request
      response - the actual HTTP response
      Throws:
      javax.servlet.ServletException
      IOException

    • initializeSession

      protected void initializeSession​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws javax.servlet.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's not invoked when a replicated session is reinstantiated in another servlet container.
      Parameters:
      request - the actual HTTP request
      response - the actual HTTP response
      Throws:
      javax.servlet.ServletException
      IOException

    • preTemplateProcess

      protected boolean preTemplateProcess​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, Template template, TemplateModel model) throws javax.servlet.ServletException, IOException
      Called before the execution is passed to Template.process(Object, java.io.Writer). This is a generic hook you might use in subclasses to perform a specific action before the template is processed.
      Parameters:
      request - The HTTP request that we will response to.
      response - The HTTP response. The HTTP headers are already initialized here, such as the conteType and the responseCharacterEncoding are already set, but you can do the final adjustments here. The response Writer isn't created yet, so changing HTTP headers and buffering parameters works.
      template - The template that will get executed
      model - The data model that will be passed to the template. By default this will be an AllHttpScopesHashModel (which is a SimpleHash subclass). Thus, you can add new variables to the data-model with the SimpleHash.put(String, Object) subclass) method. However, to adjust the data-model, overriding createModel(ObjectWrapper, ServletContext, HttpServletRequest, HttpServletResponse) is probably a more appropriate place.
      Returns:
      true to process the template, false to suppress template processing.
      Throws:
      javax.servlet.ServletException
      IOException

    • postTemplateProcess

      protected void postTemplateProcess​(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, Template template, TemplateModel data) throws javax.servlet.ServletException, IOException
      Called after the execution returns from Template.process(Object, java.io.Writer). 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.
      Parameters:
      request - the actual HTTP request
      response - the actual HTTP response
      template - the template that was executed
      data - the data that was passed to the template
      Throws:
      javax.servlet.ServletException
      IOException

    • getConfiguration

      protected Configuration getConfiguration()
      Returns the Configuration object used by this servlet. Please don't forget that Configuration is not thread-safe when you modify it.

    • getDefaultOverrideResponseContentType

      protected String getDefaultOverrideResponseContentType()
      Returns the default value of the "OverrideResponseContentType" Servlet init-param. The method inherited from FreemarkerServlet returns "always"; subclasses my override this.
      Since:
      2.3.24