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:

GenericHttpMessageConverter<Object>, org.springframework.http.converter.HttpMessageConverter<Object>

public class MappingJackson2HttpMessageConverter
extends org.springframework.http.converter.AbstractHttpMessageConverter<Object>
implements GenericHttpMessageConverter<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:

org.springframework.web.servlet.view.json.MappingJackson2JsonView

Field Summary

Fields

Modifier and Type	Field and Description
static Charset	DEFAULT_CHARSET

Constructor Summary

Constructors

Constructor and Description
MappingJackson2HttpMessageConverter() Construct a new MappingJackson2HttpMessageConverter.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	canRead(Class<?> clazz, org.springframework.http.MediaType mediaType)
boolean	canRead(Type type, org.springframework.http.MediaType mediaType) Indicates whether the given type can be read by this converter.
boolean	canWrite(Class<?> clazz, org.springframework.http.MediaType mediaType)
protected com.fasterxml.jackson.databind.JavaType	getJavaType(Type type) Return the Jackson JavaType for the specified type.
protected com.fasterxml.jackson.core.JsonEncoding	getJsonEncoding(org.springframework.http.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.
Object	read(Type type, org.springframework.http.HttpInputMessage inputMessage) Read an object of the given type form the given input message, and returns it.
protected Object	readInternal(Class<?> clazz, org.springframework.http.HttpInputMessage inputMessage)
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 "{} &&".
void	setPrettyPrint(boolean prettyPrint) Whether to use the DefaultPrettyPrinter when writing JSON.
protected boolean	supports(Class<?> clazz)
protected void	writeInternal(Object object, org.springframework.http.HttpOutputMessage outputMessage)

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

Methods inherited from interface org.springframework.http.converter.HttpMessageConverter

getSupportedMediaTypes, read, write

Field Detail

DEFAULT_CHARSET

public static final Charset DEFAULT_CHARSET

Constructor Detail

MappingJackson2HttpMessageConverter

public MappingJackson2HttpMessageConverter()

Construct a new MappingJackson2HttpMessageConverter.

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 org.codehaus.jackson.map.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.

setPrettyPrint

public void setPrettyPrint(boolean prettyPrint)

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

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

canRead

public boolean canRead(Class<?> clazz,
              org.springframework.http.MediaType mediaType)

Specified by:

canRead in interface org.springframework.http.converter.HttpMessageConverter<Object>

Overrides:

canRead in class org.springframework.http.converter.AbstractHttpMessageConverter<Object>

canRead

public boolean canRead(Type type,
              org.springframework.http.MediaType mediaType)

Description copied from interface: GenericHttpMessageConverter

Indicates whether the given type can be read by this converter.

Specified by:

canRead in interface GenericHttpMessageConverter<Object>

Parameters:

type - the type 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,
               org.springframework.http.MediaType mediaType)

Specified by:

canWrite in interface org.springframework.http.converter.HttpMessageConverter<Object>

Overrides:

canWrite in class org.springframework.http.converter.AbstractHttpMessageConverter<Object>

supports

protected boolean supports(Class<?> clazz)

Specified by:

supports in class org.springframework.http.converter.AbstractHttpMessageConverter<Object>

readInternal

protected Object readInternal(Class<?> clazz,
                  org.springframework.http.HttpInputMessage inputMessage)
                       throws IOException,
                              org.springframework.http.converter.HttpMessageNotReadableException

Specified by:

readInternal in class org.springframework.http.converter.AbstractHttpMessageConverter<Object>

Throws:

IOException

org.springframework.http.converter.HttpMessageNotReadableException

read

public Object read(Type type,
          org.springframework.http.HttpInputMessage inputMessage)
            throws IOException,
                   org.springframework.http.converter.HttpMessageNotReadableException

Description copied from interface: GenericHttpMessageConverter

Read an object of the given type form the given input message, and returns it.

Specified by:

read in interface GenericHttpMessageConverter<Object>

Parameters:

type - the type of object to return. This type must have previously been passed to the canRead method of this interface, which must have returned true.

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,
                 org.springframework.http.HttpOutputMessage outputMessage)
                      throws IOException,
                             org.springframework.http.converter.HttpMessageNotWritableException

Specified by:

writeInternal in class org.springframework.http.converter.AbstractHttpMessageConverter<Object>

Throws:

IOException

org.springframework.http.converter.HttpMessageNotWritableException

getJavaType

protected com.fasterxml.jackson.databind.JavaType getJavaType(Type type)

Return the Jackson JavaType for the specified type.

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(Type type) {
   if (type instanceof Class && List.class.isAssignableFrom((Class)type)) {
     return TypeFactory.collectionType(ArrayList.class, MyBean.class);
   } else {
     return super.getJavaType(type);
   }
 }
 

Parameters:

type - the type to return the java type for

Returns:

the java type

getJsonEncoding

protected com.fasterxml.jackson.core.JsonEncoding getJsonEncoding(org.springframework.http.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)