org.springframework.web.servlet.view.json

Class MappingJackson2JsonView

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.json.MappingJackson2JsonView

All Implemented Interfaces:

Aware, BeanNameAware, ApplicationContextAware, ServletContextAware, View

public class MappingJackson2JsonView
extends AbstractView

Spring MVC View that renders JSON content by serializing the model for the current request using Jackson 2's ObjectMapper.

By default, the entire contents of the model map (with the exception of framework-specific classes) will be encoded as JSON. If the model contains only one key, you can have it extracted encoded as JSON alone via setExtractValueFromSingleKeyModel(boolean).

Since:

3.1.2

Author:

Jeremy Grelle, Arjen Poutsma, Rossen Stoyanchev, Juergen Hoeller

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_CONTENT_TYPE Default content type: "application/json".

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
MappingJackson2JsonView() Construct a new MappingJackson2JsonView, setting the content type to application/json.

Method Summary

Modifier and Type	Method and Description
protected Object	filterModel(Map<String,Object> model) Filter out undesired attributes from the given model.
JsonEncoding	getEncoding() Return the JsonEncoding for this view.
Set<String>	getModelKeys() Return the attributes in the model that should be rendered by this view.
ObjectMapper	getObjectMapper() Return the ObjectMapper for this view.
Set<String>	getRenderedAttributes() Deprecated. use getModelKeys() instead
protected void	prepareResponse(HttpServletRequest request, HttpServletResponse response) Prepare the given response for rendering.
protected void	renderMergedOutputModel(Map<String,Object> model, HttpServletRequest request, HttpServletResponse response) Subclasses must implement this method to actually render the view.
void	setDisableCaching(boolean disableCaching) Disables caching of the generated JSON.
void	setEncoding(JsonEncoding encoding) Set the JsonEncoding for this view.
void	setExtractValueFromSingleKeyModel(boolean extractValueFromSingleKeyModel) Set whether to serialize models containing a single attribute as a map or whether to extract the single value from the model and serialize it directly.
void	setJsonPrefix(String jsonPrefix) Specify a custom prefix to use for this view's JSON output.
void	setModelKey(String modelKey) Set the attribute in the model that should be rendered by this view.
void	setModelKeys(Set<String> modelKeys) Set the attributes in the model that should be rendered by this view.
void	setObjectMapper(ObjectMapper objectMapper) Set the ObjectMapper for this view.
void	setPrefixJson(boolean prefixJson) Indicates whether the JSON output by this view should be prefixed with "{} && ".
void	setPrettyPrint(boolean prettyPrint) Whether to use the default pretty printer when writing JSON.
void	setRenderedAttributes(Set<String> renderedAttributes) Deprecated. use setModelKeys(Set) instead
void	setUpdateContentLength(boolean updateContentLength) Whether to update the 'Content-Length' header of the response.
protected void	writeContent(OutputStream stream, Object value, String jsonPrefix) Write the actual JSON content to the stream.

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

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

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

getServletContext, getTempDir, getWebApplicationContext, initApplicationContext, initServletContext, 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

DEFAULT_CONTENT_TYPE

public static final String DEFAULT_CONTENT_TYPE

Default content type: "application/json". Overridable through AbstractView.setContentType(java.lang.String).

See Also:

Constant Field Values

Constructor Detail

MappingJackson2JsonView

public MappingJackson2JsonView()

Construct a new MappingJackson2JsonView, setting the content type to application/json.

Method Detail

setObjectMapper

public void setObjectMapper(ObjectMapper objectMapper)

Set the ObjectMapper for this view. If not set, a default ObjectMapper will be used.

Setting a custom-configured ObjectMapper is one way to take further control of the JSON serialization process. The other option is to use Jackson's provided annotations on the types to be serialized, in which case a custom-configured ObjectMapper is unnecessary.

getObjectMapper

public final ObjectMapper getObjectMapper()

Return the ObjectMapper for this view.

setEncoding

public void setEncoding(JsonEncoding encoding)

Set the JsonEncoding for this view. By default, UTF-8 is used.

getEncoding

public final JsonEncoding getEncoding()

Return the JsonEncoding for this view.

setJsonPrefix

public void setJsonPrefix(String jsonPrefix)

Specify a custom prefix to use for this view's JSON output. Default is none.

See Also:

setPrefixJson(boolean)

setPrefixJson

public void setPrefixJson(boolean prefixJson)

Indicates whether the JSON output by this view should be prefixed with "{} && ". Default is false.

Prefixing the JSON string in this manner is used to help prevent JSON Hijacking. The prefix renders the string syntactically invalid as a script so that it cannot be hijacked. This prefix does not affect the evaluation of JSON, but if JSON validation is performed on the string, the prefix would need to be ignored.

See Also:

setJsonPrefix(java.lang.String)

setPrettyPrint

public void setPrettyPrint(boolean prettyPrint)

Whether to use the default pretty printer when writing JSON. This is a shortcut for setting up an ObjectMapper as follows:

 ObjectMapper mapper = new ObjectMapper();
 mapper.configure(SerializationFeature.INDENT_OUTPUT, true);
 

The default value is false.

setModelKey

public void setModelKey(String modelKey)

Set the attribute in the model that should be rendered by this view. When set, all other model attributes will be ignored.

setModelKeys

public void setModelKeys(Set<String> modelKeys)

Set the attributes in the model that should be rendered by this view. When set, all other model attributes will be ignored.

getModelKeys

public final Set<String> getModelKeys()

Return the attributes in the model that should be rendered by this view.

setRenderedAttributes

@Deprecated
public void setRenderedAttributes(Set<String> renderedAttributes)

Deprecated. use setModelKeys(Set) instead

Set the attributes in the model that should be rendered by this view. When set, all other model attributes will be ignored.

getRenderedAttributes

@Deprecated
public final Set<String> getRenderedAttributes()

Deprecated. use getModelKeys() instead

Return the attributes in the model that should be rendered by this view.

setExtractValueFromSingleKeyModel

public void setExtractValueFromSingleKeyModel(boolean extractValueFromSingleKeyModel)

Set whether to serialize models containing a single attribute as a map or whether to extract the single value from the model and serialize it directly.

The effect of setting this flag is similar to using MappingJacksonHttpMessageConverter with an @ResponseBody request-handling method.

Default is false.

setDisableCaching

public void setDisableCaching(boolean disableCaching)

Disables caching of the generated JSON.

Default is true, which will prevent the client from caching the generated JSON.

setUpdateContentLength

public void setUpdateContentLength(boolean updateContentLength)

Whether to update the 'Content-Length' header of the response. When set to true, the response is buffered in order to determine the content length and set the 'Content-Length' header of the response.

The default setting is false.

prepareResponse

protected void prepareResponse(HttpServletRequest request,
                               HttpServletResponse response)

Description copied from class: AbstractView

Prepare the given response for rendering.

The default implementation applies a workaround for an IE bug when sending download content via HTTPS.

Overrides:

prepareResponse in class AbstractView

Parameters:

request - current HTTP request

response - current HTTP response

renderMergedOutputModel

protected void renderMergedOutputModel(Map<String,Object> model,
                                       HttpServletRequest request,
                                       HttpServletResponse response)
                                throws Exception

Description copied from class: AbstractView

Subclasses must implement this method to actually render the view.

The first step will be preparing the request: In the JSP case, this would mean setting model objects as request attributes. The second step will be the actual rendering of the view, for example including the JSP via a RequestDispatcher.

Specified by:

renderMergedOutputModel in class AbstractView

Parameters:

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

request - current HTTP request

response - current HTTP response

Throws:

Exception - if rendering failed

filterModel

protected Object filterModel(Map<String,Object> model)

Filter out undesired attributes from the given model. The return value can be either another Map or a single value object.

The default implementation removes BindingResult instances and entries not included in the renderedAttributes property.

Parameters:

model - the model, as passed on to renderMergedOutputModel(java.util.Map<java.lang.String, java.lang.Object>, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

Returns:

the value to be rendered

writeContent

protected void writeContent(OutputStream stream,
                            Object value,
                            String jsonPrefix)
                     throws IOException

Write the actual JSON content to the stream.

Parameters:

stream - the output stream to use

value - the value to be rendered, as returned from filterModel(java.util.Map<java.lang.String, java.lang.Object>)

jsonPrefix - the prefix for this view's JSON output (as indicated through setJsonPrefix(java.lang.String)/setPrefixJson(boolean))

Throws:

IOException - if writing failed