org.springframework.http.converter.json
Class MappingJackson2HttpMessageConverter

java.lang.Object
  org.springframework.http.converter.AbstractHttpMessageConverter<Object>
      org.springframework.http.converter.json.MappingJackson2HttpMessageConverter

All Implemented Interfaces:

HttpMessageConverter<Object>

public class MappingJackson2HttpMessageConverter
extends AbstractHttpMessageConverter<Object>

Implementation of HttpMessageConverter that can read and write JSON using Jackson 2's ObjectMapper.

This converter can be used to bind to typed beans, or untyped HashMap instances.

By default, this converter supports application/json. This can be overridden by setting the supportedMediaTypes property.

Since:

3.1.2

Author:

Arjen Poutsma, Keith Donald

See Also:

MappingJackson2JsonView

Field Summary

static Charset

DEFAULT_CHARSET

Fields inherited from class org.springframework.http.converter.AbstractHttpMessageConverter

logger

Constructor Summary

MappingJackson2HttpMessageConverter()
Construct a new BindingJacksonHttpMessageConverter.

Method Summary

boolean	canRead(Class<?> clazz, MediaType mediaType) This implementation checks if the given class is supported, and if the supported media types include the given media type.
boolean	canWrite(Class<?> clazz, MediaType mediaType) This implementation checks if the given class is supported, and if the supported media types include the given media type.
protected com.fasterxml.jackson.databind.JavaType	getJavaType(Class<?> clazz) Return the Jackson JavaType for the specified class.
protected com.fasterxml.jackson.core.JsonEncoding	getJsonEncoding(MediaType contentType) Determine the JSON encoding to use for the given content type.
com.fasterxml.jackson.databind.ObjectMapper	getObjectMapper() Return the underlying ObjectMapper for this view.
protected Object	readInternal(Class<?> clazz, HttpInputMessage inputMessage) Abstract template method that reads the actualy object.
void	setObjectMapper(com.fasterxml.jackson.databind.ObjectMapper objectMapper) Set the ObjectMapper for this view.
void	setPrefixJson(boolean prefixJson) Indicate whether the JSON output by this view should be prefixed with "{} &&".
protected boolean	supports(Class<?> clazz) Indicates whether the given class is supported by this converter.
protected void	writeInternal(Object object, HttpOutputMessage outputMessage) Abstract template method that writes the actual body.

Methods inherited from class org.springframework.http.converter.AbstractHttpMessageConverter

canRead, canWrite, getContentLength, getDefaultContentType, getSupportedMediaTypes, read, setSupportedMediaTypes, write

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_CHARSET

public static final Charset DEFAULT_CHARSET

Constructor Detail

MappingJackson2HttpMessageConverter

public MappingJackson2HttpMessageConverter()

Construct a new BindingJacksonHttpMessageConverter.

Method Detail

setObjectMapper

public void setObjectMapper(com.fasterxml.jackson.databind.ObjectMapper objectMapper)

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

Setting a custom-configured ObjectMapper is one way to take further control of the JSON serialization process. For example, an extended SerializerFactory can be configured that provides custom serializers for specific types. The other option for refining the serialization process is to use Jackson's provided annotations on the types to be serialized, in which case a custom-configured ObjectMapper is unnecessary.

getObjectMapper

public com.fasterxml.jackson.databind.ObjectMapper getObjectMapper()

Return the underlying ObjectMapper for this view.

setPrefixJson

public void setPrefixJson(boolean prefixJson)

Indicate 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.

canRead

public boolean canRead(Class<?> clazz,
                       MediaType mediaType)

Description copied from class: AbstractHttpMessageConverter

This implementation checks if the given class is supported, and if the supported media types include the given media type.

Specified by:

canRead in interface HttpMessageConverter<Object>

Overrides:

canRead in class AbstractHttpMessageConverter<Object>

Parameters:

clazz - the class to test for readability

mediaType - the media type to read, can be null if not specified. Typically the value of a Content-Type header.

Returns:

true if readable; false otherwise

canWrite

public boolean canWrite(Class<?> clazz,
                        MediaType mediaType)

Description copied from class: AbstractHttpMessageConverter

This implementation checks if the given class is supported, and if the supported media types include the given media type.

Specified by:

canWrite in interface HttpMessageConverter<Object>

Overrides:

canWrite in class AbstractHttpMessageConverter<Object>

Parameters:

clazz - the class to test for writability

mediaType - the media type to write, can be null if not specified. Typically the value of an Accept header.

Returns:

true if writable; false otherwise

supports

protected boolean supports(Class<?> clazz)

Description copied from class: AbstractHttpMessageConverter

Indicates whether the given class is supported by this converter.

Specified by:

supports in class AbstractHttpMessageConverter<Object>

Parameters:

clazz - the class to test for support

Returns:

true if supported; false otherwise

readInternal

protected Object readInternal(Class<?> clazz,
                              HttpInputMessage inputMessage)
                       throws IOException,
                              HttpMessageNotReadableException

Description copied from class: AbstractHttpMessageConverter

Abstract template method that reads the actualy object. Invoked from AbstractHttpMessageConverter.read(java.lang.Class, org.springframework.http.HttpInputMessage).

Specified by:

readInternal in class AbstractHttpMessageConverter<Object>

Parameters:

clazz - the type of object to return

inputMessage - the HTTP input message to read from

Returns:

the converted object

Throws:

IOException - in case of I/O errors

HttpMessageNotReadableException - in case of conversion errors

writeInternal

protected void writeInternal(Object object,
                             HttpOutputMessage outputMessage)
                      throws IOException,
                             HttpMessageNotWritableException

Description copied from class: AbstractHttpMessageConverter

Abstract template method that writes the actual body. Invoked from AbstractHttpMessageConverter.write(T, org.springframework.http.MediaType, org.springframework.http.HttpOutputMessage).

Specified by:

writeInternal in class AbstractHttpMessageConverter<Object>

Parameters:

object - the object to write to the output message

outputMessage - the message to write to

Throws:

IOException - in case of I/O errors

HttpMessageNotWritableException - in case of conversion errors

getJavaType

protected com.fasterxml.jackson.databind.JavaType getJavaType(Class<?> clazz)

Return the Jackson JavaType for the specified class.

The default implementation returns ObjectMapper.constructType(java.lang.reflect.Type), but this can be overridden in subclasses, to allow for custom generic collection handling. For instance:

 protected JavaType getJavaType(Class<?> clazz) {
   if (List.class.isAssignableFrom(clazz)) {
     return objectMapper.getTypeFactory().constructCollectionType(ArrayList.class, MyBean.class);
   } else {
     return super.getJavaType(clazz);
   }
 }
 

Parameters:

clazz - the class to return the java type for

Returns:

the java type

getJsonEncoding

protected com.fasterxml.jackson.core.JsonEncoding getJsonEncoding(MediaType contentType)

Determine the JSON encoding to use for the given content type.

Parameters:

contentType - the media type as requested by the caller

Returns:

the JSON encoding to use (never null)