org.springframework.web.servlet.view.freemarker

Class FreeMarkerView

java.lang.Object

org.springframework.context.support.ApplicationObjectSupport

org.springframework.web.context.support.WebApplicationObjectSupport

org.springframework.web.servlet.view.AbstractView

org.springframework.web.servlet.view.AbstractUrlBasedView

org.springframework.web.servlet.view.AbstractTemplateView

org.springframework.web.servlet.view.freemarker.FreeMarkerView

All Implemented Interfaces:

Aware, BeanNameAware, InitializingBean, ApplicationContextAware, ServletContextAware, View

public class FreeMarkerView
extends AbstractTemplateView

View using the FreeMarker template engine.

Exposes the following JavaBean properties:

• url: the location of the FreeMarker template to be wrapped, relative to the FreeMarker template context (directory).
• encoding (optional, default is determined by FreeMarker configuration): the encoding of the FreeMarker template file

Depends on a single FreeMarkerConfig object such as FreeMarkerConfigurer being accessible in the current web application context, with any bean name. Alternatively, you can set the FreeMarker Configuration object as bean property. See setConfiguration(Configuration) for more details on the impacts of this approach.

Note: Spring's FreeMarker support requires FreeMarker 2.3 or higher.

Since:

03.03.2004

Author:

Darren Davison, Juergen Hoeller

See Also:

AbstractUrlBasedView.setUrl(java.lang.String), AbstractTemplateView.setExposeSpringMacroHelpers(boolean), setEncoding(java.lang.String), setConfiguration(Configuration), FreeMarkerConfig, FreeMarkerConfigurer

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	FreeMarkerView.DelegatingServletConfig Internal implementation of the ServletConfig interface, to be passed to the servlet adapter.
private static class	FreeMarkerView.GenericServletAdapter Simple adapter class that extends GenericServlet.

Field Summary

Fields

Modifier and Type	Field and Description
private Configuration	configuration
private java.lang.String	encoding
private ServletContextHashModel	servletContextHashModel
private TaglibFactory	taglibFactory

Fields inherited from class org.springframework.web.servlet.view.AbstractTemplateView

SPRING_MACRO_REQUEST_CONTEXT_ATTRIBUTE

Fields inherited from class org.springframework.web.servlet.view.AbstractView

DEFAULT_CONTENT_TYPE

Fields inherited from class org.springframework.context.support.ApplicationObjectSupport

logger

Fields inherited from interface org.springframework.web.servlet.View

PATH_VARIABLES, RESPONSE_STATUS_ATTRIBUTE, SELECTED_CONTENT_TYPE

Constructor Summary

Constructors

Constructor and Description
FreeMarkerView()

Method Summary

Modifier and Type	Method and Description
protected FreeMarkerConfig	autodetectConfiguration() Autodetect a FreeMarkerConfig object via the ApplicationContext.
private HttpSessionHashModel	buildSessionModel(HttpServletRequest request, HttpServletResponse response) Build a FreeMarker HttpSessionHashModel for the given request, detecting whether a session already exists and reacting accordingly.
protected SimpleHash	buildTemplateModel(java.util.Map<java.lang.String,java.lang.Object> model, HttpServletRequest request, HttpServletResponse response) Build a FreeMarker template model for the given model Map.
boolean	checkResource(java.util.Locale locale) Check that the FreeMarker template used for this view exists and is valid.
protected void	doRender(java.util.Map<java.lang.String,java.lang.Object> model, HttpServletRequest request, HttpServletResponse response) Render the FreeMarker view to the given response, using the given model map which contains the complete template model to use.
protected void	exposeHelpers(java.util.Map<java.lang.String,java.lang.Object> model, HttpServletRequest request) Expose helpers unique to each rendering operation.
protected Configuration	getConfiguration() Return the FreeMarker configuration used by this view.
protected java.lang.String	getEncoding() Return the encoding for the FreeMarker template.
protected ObjectWrapper	getObjectWrapper() Return the configured FreeMarker ObjectWrapper, or the default wrapper if none specified.
protected Template	getTemplate(java.util.Locale locale) Retrieve the FreeMarker template for the given locale, to be rendering by this view.
protected Template	getTemplate(java.lang.String name, java.util.Locale locale) Retrieve the FreeMarker template specified by the given name, using the encoding specified by the "encoding" bean property.
protected void	initServletContext(ServletContext servletContext) Invoked on startup.
protected void	processTemplate(Template template, SimpleHash model, HttpServletResponse response) Process the FreeMarker template to the servlet response.
protected void	renderMergedTemplateModel(java.util.Map<java.lang.String,java.lang.Object> model, HttpServletRequest request, HttpServletResponse response) Process the model map by merging it with the FreeMarker template.
void	setConfiguration(Configuration configuration) Set the FreeMarker Configuration to be used by this view.
void	setEncoding(java.lang.String encoding) Set the encoding of the FreeMarker template file.

Methods inherited from class org.springframework.web.servlet.view.AbstractTemplateView

applyContentType, renderMergedOutputModel, setAllowRequestOverride, setAllowSessionOverride, setExposeRequestAttributes, setExposeSessionAttributes, setExposeSpringMacroHelpers

Methods inherited from class org.springframework.web.servlet.view.AbstractUrlBasedView

afterPropertiesSet, getUrl, isUrlRequired, setUrl, toString

Methods inherited from class org.springframework.web.servlet.view.AbstractView

addStaticAttribute, createMergedOutputModel, createRequestContext, createTemporaryOutputStream, exposeModelAsRequestAttributes, generatesDownloadContent, getAttributesMap, getBeanName, getContentType, getRequestContextAttribute, getRequestToExpose, getStaticAttributes, isExposePathVariables, prepareResponse, render, setAttributes, setAttributesCSV, setAttributesMap, setBeanName, setContentType, setExposeContextBeansAsAttributes, setExposedContextBeanNames, setExposePathVariables, setRequestContextAttribute, setResponseContentType, writeToResponse

Methods inherited from class org.springframework.web.context.support.WebApplicationObjectSupport

getServletContext, getTempDir, getWebApplicationContext, initApplicationContext, isContextRequired, setServletContext

Methods inherited from class org.springframework.context.support.ApplicationObjectSupport

getApplicationContext, getMessageSourceAccessor, initApplicationContext, requiredContextClass, setApplicationContext

Methods inherited from class java.lang.Object

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

Field Detail

encoding

private java.lang.String encoding

configuration

private Configuration configuration

taglibFactory

private TaglibFactory taglibFactory

servletContextHashModel

private ServletContextHashModel servletContextHashModel

Constructor Detail

FreeMarkerView

public FreeMarkerView()

Method Detail

setEncoding

public void setEncoding(java.lang.String encoding)

Set the encoding of the FreeMarker template file. Default is determined by the FreeMarker Configuration: "ISO-8859-1" if not specified otherwise.

Specify the encoding in the FreeMarker Configuration rather than per template if all your templates share a common encoding.

getEncoding

protected java.lang.String getEncoding()

Return the encoding for the FreeMarker template.

setConfiguration

public void setConfiguration(Configuration configuration)

Set the FreeMarker Configuration to be used by this view.

If this is not set, the default lookup will occur: a single FreeMarkerConfig is expected in the current web application context, with any bean name. Note: using this method will cause a new instance of TaglibFactory to created for every single FreeMarkerView instance. This can be quite expensive in terms of memory and initial CPU usage. In production it is recommended that you use a FreeMarkerConfig which exposes a single shared TaglibFactory.

getConfiguration

protected Configuration getConfiguration()

Return the FreeMarker configuration used by this view.

initServletContext

protected void initServletContext(ServletContext servletContext)
                           throws BeansException

Invoked on startup. Looks for a single FreeMarkerConfig bean to find the relevant Configuration for this factory.

Checks that the template for the default Locale can be found: FreeMarker will check non-Locale-specific templates if a locale-specific one is not found.

Overrides:

initServletContext in class WebApplicationObjectSupport

Parameters:

servletContext - the ServletContext that this application object runs in (never null)

Throws:

BeansException

See Also:

freemarker.cache.TemplateCache#getTemplate

autodetectConfiguration

protected FreeMarkerConfig autodetectConfiguration()
                                            throws BeansException

Autodetect a FreeMarkerConfig object via the ApplicationContext.

Returns:

the Configuration instance to use for FreeMarkerViews

Throws:

BeansException - if no Configuration instance could be found

See Also:

ApplicationObjectSupport.getApplicationContext(), setConfiguration(Configuration)

getObjectWrapper

protected ObjectWrapper getObjectWrapper()

Return the configured FreeMarker ObjectWrapper, or the default wrapper if none specified.

See Also:

freemarker.template.Configuration#getObjectWrapper()

checkResource

public boolean checkResource(java.util.Locale locale)
                      throws java.lang.Exception

Check that the FreeMarker template used for this view exists and is valid.

Can be overridden to customize the behavior, for example in case of multiple templates to be rendered into a single view.

Overrides:

checkResource in class AbstractUrlBasedView

Parameters:

locale - the desired Locale that we're looking for

Returns:

true if the resource exists (or is assumed to exist); false if we know that it does not exist

Throws:

java.lang.Exception - if the resource exists but is invalid (e.g. could not be parsed)

renderMergedTemplateModel

protected void renderMergedTemplateModel(java.util.Map<java.lang.String,java.lang.Object> model,
                                         HttpServletRequest request,
                                         HttpServletResponse response)
                                  throws java.lang.Exception

Process the model map by merging it with the FreeMarker template. Output is directed to the servlet response.

This method can be overridden if custom behavior is needed.

Specified by:

renderMergedTemplateModel in class AbstractTemplateView

Parameters:

model - combined output Map, with request attributes and session attributes merged into it if required

request - current HTTP request

response - current HTTP response

Throws:

java.lang.Exception - if rendering failed

exposeHelpers

protected void exposeHelpers(java.util.Map<java.lang.String,java.lang.Object> model,
                             HttpServletRequest request)
                      throws java.lang.Exception

Expose helpers unique to each rendering operation. This is necessary so that different rendering operations can't overwrite each other's formats etc.

Called by renderMergedTemplateModel. The default implementation is empty. This method can be overridden to add custom helpers to the model.

Parameters:

model - The model that will be passed to the template at merge time

request - current HTTP request

Throws:

java.lang.Exception - if there's a fatal error while we're adding information to the context

See Also:

renderMergedTemplateModel(java.util.Map<java.lang.String, java.lang.Object>, HttpServletRequest, HttpServletResponse)

doRender

protected void doRender(java.util.Map<java.lang.String,java.lang.Object> model,
                        HttpServletRequest request,
                        HttpServletResponse response)
                 throws java.lang.Exception

Render the FreeMarker view to the given response, using the given model map which contains the complete template model to use.

The default implementation renders the template specified by the "url" bean property, retrieved via getTemplate. It delegates to the processTemplate method to merge the template instance with the given template model.

Adds the standard Freemarker hash models to the model: request parameters, request, session and application (ServletContext), as well as the JSP tag library hash model.

Can be overridden to customize the behavior, for example to render multiple templates into a single view.

Parameters:

model - the model to use for rendering

request - current HTTP request

response - current servlet response

Throws:

java.io.IOException - if the template file could not be retrieved

java.lang.Exception - if rendering failed

See Also:

AbstractUrlBasedView.setUrl(java.lang.String), RequestContextUtils.getLocale(HttpServletRequest), getTemplate(java.util.Locale), processTemplate(Template, SimpleHash, HttpServletResponse), freemarker.ext.servlet.FreemarkerServlet

buildTemplateModel

protected SimpleHash buildTemplateModel(java.util.Map<java.lang.String,java.lang.Object> model,
                                        HttpServletRequest request,
                                        HttpServletResponse response)

Build a FreeMarker template model for the given model Map.

The default implementation builds a AllHttpScopesHashModel.

Parameters:

model - the model to use for rendering

request - current HTTP request

response - current servlet response

Returns:

the FreeMarker template model, as a SimpleHash or subclass thereof

buildSessionModel

private HttpSessionHashModel buildSessionModel(HttpServletRequest request,
                                               HttpServletResponse response)

Build a FreeMarker HttpSessionHashModel for the given request, detecting whether a session already exists and reacting accordingly.

Parameters:

request - current HTTP request

response - current servlet response

Returns:

the FreeMarker HttpSessionHashModel

getTemplate

protected Template getTemplate(java.util.Locale locale)
                        throws java.io.IOException

Retrieve the FreeMarker template for the given locale, to be rendering by this view.

By default, the template specified by the "url" bean property will be retrieved.

Parameters:

locale - the current locale

Returns:

the FreeMarker template to render

Throws:

java.io.IOException - if the template file could not be retrieved

See Also:

AbstractUrlBasedView.setUrl(java.lang.String), getTemplate(String, java.util.Locale)

getTemplate

protected Template getTemplate(java.lang.String name,
                               java.util.Locale locale)
                        throws java.io.IOException

Retrieve the FreeMarker template specified by the given name, using the encoding specified by the "encoding" bean property.

Can be called by subclasses to retrieve a specific template, for example to render multiple templates into a single view.

Parameters:

name - the file name of the desired template

locale - the current locale

Returns:

the FreeMarker template

Throws:

java.io.IOException - if the template file could not be retrieved

processTemplate

protected void processTemplate(Template template,
                               SimpleHash model,
                               HttpServletResponse response)
                        throws java.io.IOException,
                               TemplateException

Process the FreeMarker template to the servlet response.

Can be overridden to customize the behavior.

Parameters:

template - the template to process

model - the model for the template

response - servlet response (use this to get the OutputStream or Writer)

Throws:

java.io.IOException - if the template file could not be retrieved

TemplateException - if thrown by FreeMarker

See Also:

freemarker.template.Template#process(Object, java.io.Writer)