Class FreeMarkerView

java.lang.Object

org.springframework.web.reactive.result.view.AbstractView

org.springframework.web.reactive.result.view.AbstractUrlBasedView

org.springframework.web.reactive.result.view.freemarker.FreeMarkerView

All Implemented Interfaces:

Aware, BeanNameAware, InitializingBean, ApplicationContextAware, View

public class FreeMarkerView
extends AbstractUrlBasedView

A View implementation that uses the FreeMarker template engine.

Exposes the following configuration properties:

• url: the location of the FreeMarker template relative to the FreeMarkerConfigurer's templateLoaderPath.
• encoding: the encoding used to decode byte sequences to character sequences when reading the FreeMarker template file. Default is determined by the FreeMarker Configuration.

Depends on a single FreeMarkerConfig object such as FreeMarkerConfigurer being accessible in the application context. Alternatively the FreeMarker Configuration can be set directly via setConfiguration(Configuration).

Note: To ensure that the correct encoding is used when rendering the response as well as when the client reads the response, the following steps must be taken.

• Either set the default encoding in the FreeMarker Configuration or set the encoding for this view.
• Configure the supported media type with a charset equal to the configured encoding via AbstractView.setSupportedMediaTypes(java.util.List) or ViewResolverSupport.setSupportedMediaTypes(java.util.List).

Note, however, that FreeMarkerConfigurer sets the default encoding in the FreeMarker Configuration to "UTF-8" and that AbstractView sets the supported media type to "text/html;charset=UTF-8" by default. Thus, those default values are likely suitable for most applications.

Note: Spring's FreeMarker support requires FreeMarker 2.3.33 or higher.

Since:

5.0

Author:

Rossen Stoyanchev, Sam Brannen

Field Summary

Fields

Modifier and Type	Field	Description
static final String	SPRING_MACRO_REQUEST_CONTEXT_ATTRIBUTE	Attribute name of the RequestContext instance in the template model, available to Spring's macros — for example, for creating BindStatus objects.

Fields inherited from class AbstractView

logger, REQUEST_DATA_VALUE_PROCESSOR_BEAN_NAME

Fields inherited from interface View

BINDING_CONTEXT_ATTRIBUTE

Constructor Summary

Constructors

Constructor	Description
FreeMarkerView()

Method Summary

Modifier and Type	Method	Description
void	afterPropertiesSet()	Invoked by the containing BeanFactory after it has set all bean properties and satisfied BeanFactoryAware, ApplicationContextAware etc.
protected FreeMarkerConfig	autodetectConfiguration()	Autodetect a FreeMarkerConfig object in the ApplicationContext.
boolean	checkResourceExists(Locale locale)	Check that the FreeMarker template used for this view exists and is valid.
protected @nullable freemarker.template.Configuration	getConfiguration()	Get the FreeMarker Configuration used by this view.
protected @nullable String	getEncoding()	Get the encoding used to decode byte sequences to character sequences when reading the FreeMarker template file for this view, or null to signal that the FreeMarker Configuration should be used to determine the encoding.
protected reactor.core.publisher.Mono<Map<String,Object>>	getModelAttributes(@nullable Map<String,?> model, ServerWebExchange exchange)	Prepare the model to use for rendering by potentially exposing a RequestContext for use in Spring FreeMarker macros and then delegating to the inherited implementation of this method.
protected freemarker.template.ObjectWrapper	getObjectWrapper()	Get the configured FreeMarker ObjectWrapper, or the default wrapper if none specified.
protected freemarker.template.SimpleHash	getTemplateModel(Map<String,Object> model, ServerWebExchange exchange)	Build a FreeMarker template model for the given model map.
protected reactor.core.publisher.Mono<freemarker.template.Template>	lookupTemplate(Locale locale)	Retrieve the FreeMarker Template to be rendered by this view, for the specified locale and using the configured encoding if set.
protected freemarker.template.Configuration	obtainConfiguration()	Obtain the FreeMarker Configuration for actual use.
protected reactor.core.publisher.Mono<Void>	renderInternal(Map<String,Object> renderAttributes, @nullable MediaType contentType, ServerWebExchange exchange)	Subclasses must implement this method to actually render the view.
reactor.core.publisher.Mono<Boolean>	resourceExists(Locale locale)	Check that the FreeMarker template used for this view exists and is valid.
void	setCharset(@nullable Charset charset)	Set the Charset used to decode byte sequences to character sequences when reading the FreeMarker template file for this view.
void	setConfiguration(@nullable freemarker.template.Configuration configuration)	Set the FreeMarker Configuration to be used by this view.
void	setEncoding(@nullable String encoding)	Set the encoding used to decode byte sequences to character sequences when reading the FreeMarker template file for this view.
void	setExposeSpringMacroHelpers(boolean exposeSpringMacroHelpers)	Set whether to expose a RequestContext for use by Spring's macro library, under the name "springMacroRequestContext".

Methods inherited from class AbstractUrlBasedView

getUrl, setUrl, toString

Methods inherited from class AbstractView

createRequestContext, formatViewName, getApplicationContext, getBeanName, getDefaultCharset, getRequestContextAttribute, getRequestDataValueProcessor, getSupportedMediaTypes, obtainApplicationContext, render, resolveAsyncAttributes, setApplicationContext, setBeanName, setDefaultCharset, setRequestContextAttribute, setSupportedMediaTypes

Methods inherited from class Object

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

Methods inherited from interface View

isRedirectView

Field Details

SPRING_MACRO_REQUEST_CONTEXT_ATTRIBUTE

public static final String SPRING_MACRO_REQUEST_CONTEXT_ATTRIBUTE

Attribute name of the RequestContext instance in the template model, available to Spring's macros — for example, for creating BindStatus objects.

Since:

5.2

See Also:

• setExposeSpringMacroHelpers(boolean)
• Constant Field Values

Constructor Details

FreeMarkerView

public FreeMarkerView()

Method Details

setConfiguration

public void setConfiguration(@nullable freemarker.template.Configuration configuration)

Set the FreeMarker Configuration to be used by this view.

Typically this property is not set directly. Instead a single FreeMarkerConfig is expected in the Spring application context which is used to obtain the FreeMarker configuration.

getConfiguration

protected @nullable freemarker.template.Configuration getConfiguration()

Get the FreeMarker Configuration used by this view.

obtainConfiguration

protected freemarker.template.Configuration obtainConfiguration()

Obtain the FreeMarker Configuration for actual use.

Returns:

the FreeMarker configuration (never null)

Throws:

IllegalStateException - in case of no Configuration object set

See Also:

• getConfiguration()

setEncoding

public void setEncoding(@nullable String encoding)

Set the encoding used to decode byte sequences to character sequences when reading the FreeMarker template file for this view.

Defaults to null to signal that the FreeMarker Configuration should be used to determine the encoding.

A non-null encoding will override the default encoding determined by the FreeMarker Configuration.

If the encoding is not explicitly set here or in the FreeMarker Configuration, FreeMarker will read template files using the platform file encoding (defined by the JVM system property file.encoding) or UTF-8 if the platform file encoding is undefined. Note, however, that FreeMarkerConfigurer sets the default encoding in the FreeMarker Configuration to "UTF-8".

It's recommended to specify the encoding in the FreeMarker Configuration rather than per template if all your templates share a common encoding.

Note that the specified or default encoding is not used for template rendering. Instead, an explicit encoding must be specified for the rendering process. See the note in the class-level documentation for details.

See Also:

• Configuration.setDefaultEncoding(String)
• setCharset(Charset)
• getEncoding()

setCharset

public void setCharset(@nullable Charset charset)

Set the Charset used to decode byte sequences to character sequences when reading the FreeMarker template file for this view.

See setEncoding(String) for details.

Since:

6.2

See Also:

• StandardCharsets

getEncoding

protected @nullable String getEncoding()

Get the encoding used to decode byte sequences to character sequences when reading the FreeMarker template file for this view, or null to signal that the FreeMarker Configuration should be used to determine the encoding.

See Also:

• setEncoding(String)

setExposeSpringMacroHelpers

public void setExposeSpringMacroHelpers(boolean exposeSpringMacroHelpers)

Set whether to expose a RequestContext for use by Spring's macro library, under the name "springMacroRequestContext".

Default is true.

Needed for Spring's FreeMarker default macros. Note that this is not required for templates that use HTML forms unless you wish to take advantage of the Spring helper macros.

Since:

5.2

See Also:

• SPRING_MACRO_REQUEST_CONTEXT_ATTRIBUTE

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Description copied from interface: InitializingBean

Invoked by the containing BeanFactory after it has set all bean properties and satisfied BeanFactoryAware, ApplicationContextAware etc.

This method allows the bean instance to perform validation of its overall configuration and final initialization when all bean properties have been set.

Specified by:

afterPropertiesSet in interface InitializingBean

Overrides:

afterPropertiesSet in class AbstractUrlBasedView

Throws:

Exception - in the event of misconfiguration (such as failure to set an essential property) or if initialization fails for any other reason

autodetectConfiguration

protected FreeMarkerConfig autodetectConfiguration()
                                            throws BeansException

Autodetect a FreeMarkerConfig object in the ApplicationContext.

Returns:

the FreeMarkerConfig instance to use for this view

Throws:

BeansException - if no FreeMarkerConfig instance could be found

See Also:

• setConfiguration(Configuration)

checkResourceExists

public boolean checkResourceExists(Locale locale)

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.

Specified by:

checkResourceExists in class AbstractUrlBasedView

Parameters:

locale - the desired Locale that we're looking for

Returns:

false if the resource exists false if we know that it does not exist

resourceExists

public reactor.core.publisher.Mono<Boolean> resourceExists(Locale locale)

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:

resourceExists in class AbstractUrlBasedView

Parameters:

locale - the desired Locale that we're looking for

Returns:

false if the resource exists false if we know that it does not exist

Since:

6.1

getModelAttributes

protected reactor.core.publisher.Mono<Map<String,Object>> getModelAttributes(@nullable Map<String,?> model,
 ServerWebExchange exchange)

Prepare the model to use for rendering by potentially exposing a RequestContext for use in Spring FreeMarker macros and then delegating to the inherited implementation of this method.

Overrides:

getModelAttributes in class AbstractView

Since:

5.2

See Also:

• setExposeSpringMacroHelpers(boolean)
• AbstractView.getModelAttributes(Map, ServerWebExchange)

renderInternal

protected reactor.core.publisher.Mono<Void> renderInternal(Map<String,Object> renderAttributes,
 @nullable MediaType contentType,
 ServerWebExchange exchange)

Description copied from class: AbstractView

Subclasses must implement this method to actually render the view.

Specified by:

renderInternal in class AbstractView

Parameters:

renderAttributes - combined output Map (never null), with dynamic values taking precedence over static attributes

contentType - the content type selected to render with, which should match one of the supported media types

exchange - current exchange

Returns:

a Mono that represents when and if rendering succeeds

getTemplateModel

protected freemarker.template.SimpleHash getTemplateModel(Map<String,Object> model,
 ServerWebExchange exchange)

Build a FreeMarker template model for the given model map.

The default implementation builds a SimpleHash.

Parameters:

model - the model to use for rendering

exchange - current exchange

Returns:

the FreeMarker template model, as a SimpleHash or subclass thereof

getObjectWrapper

protected freemarker.template.ObjectWrapper getObjectWrapper()

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

See Also:

• Configurable.getObjectWrapper()

lookupTemplate

protected reactor.core.publisher.Mono<freemarker.template.Template> lookupTemplate(Locale locale)

Retrieve the FreeMarker Template to be rendered by this view, for the specified locale and using the configured encoding if set.

By default, the template specified by the "url" bean property will be retrieved, and the returned mono will subscribe on the bounded elastic scheduler as template lookups can be blocking operations.

Parameters:

locale - the current locale

Returns:

the FreeMarker template to render

Since:

6.1