Package org.springframework.integration.json

Class JsonToObjectTransformer

java.lang.Object

org.springframework.integration.context.IntegrationObjectSupport

org.springframework.integration.transformer.AbstractTransformer

org.springframework.integration.json.JsonToObjectTransformer

All Implemented Interfaces:

Aware, BeanClassLoaderAware, BeanFactoryAware, BeanNameAware, InitializingBean, ApplicationContextAware, ExpressionCapable, GenericTransformer<Message<?>,Message<?>>, NamedComponent, Transformer

public class JsonToObjectTransformer
extends AbstractTransformer
implements BeanClassLoaderAware

Transformer implementation that converts a JSON string payload into an instance of the provided target Class. By default this transformer uses JsonObjectMapperProvider factory to get an instance of Jackson JSON-processor if jackson-databind lib is present on the classpath. Any other JsonObjectMapper implementation can be provided.

Since version 3.0, you can omit the target class and the target type can be determined by the JsonHeaders type entries - including the contents of a one-level container or map type.

The type headers can be classes or fully-qualified class names.

Since version 5.2.6, a SpEL expression option is provided to let to build a target ResolvableType somehow externally.

Since:

2.0

Author:

Mark Fisher, Artem Bilan

See Also:

• JsonObjectMapper
• JsonObjectMapperProvider
• ResolvableType

Field Summary

Fields inherited from class org.springframework.integration.context.IntegrationObjectSupport

EXPRESSION_PARSER, logger

Constructor Summary

Constructors

Constructor	Description
JsonToObjectTransformer()
JsonToObjectTransformer(Class<?> targetClass)
JsonToObjectTransformer(Class<?> targetClass, JsonObjectMapper<?,?> jsonObjectMapper)
JsonToObjectTransformer(ResolvableType targetType)	Construct an instance based on the provided ResolvableType.
JsonToObjectTransformer(ResolvableType targetType, JsonObjectMapper<?,?> jsonObjectMapper)	Construct an instance based on the provided ResolvableType and JsonObjectMapper.
JsonToObjectTransformer(JsonObjectMapper<?,?> jsonObjectMapper)

Method Summary

Modifier and Type	Method	Description
protected Object	doTransform(Message<?> message)	Subclasses must implement this method to provide the transformation logic.
String	getComponentType()	Subclasses may implement this method to provide component type information.
protected void	onInit()	Subclasses may implement this for initialization logic.
void	setBeanClassLoader(ClassLoader classLoader)
void	setValueTypeExpression(Expression valueTypeExpression)	Configure a SpEL Expression to evaluate a ResolvableType to instantiate the payload from the incoming JSON.
void	setValueTypeExpressionString(String valueTypeExpressionString)	Configure a SpEL expression to evaluate a ResolvableType to instantiate the payload from the incoming JSON.

Methods inherited from class org.springframework.integration.transformer.AbstractTransformer

transform

Methods inherited from class org.springframework.integration.context.IntegrationObjectSupport

afterPropertiesSet, extractTypeIfPossible, generateId, getApplicationContext, getApplicationContextId, getBeanDescription, getBeanFactory, getBeanName, getChannelResolver, getComponentName, getConversionService, getExpression, getIntegrationProperties, getMessageBuilderFactory, getTaskScheduler, isInitialized, setApplicationContext, setBeanFactory, setBeanName, setChannelResolver, setComponentName, setConversionService, setMessageBuilderFactory, setPrimaryExpression, setTaskScheduler, toString

Methods inherited from class java.lang.Object

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

Constructor Details

JsonToObjectTransformer

public JsonToObjectTransformer()

JsonToObjectTransformer

public JsonToObjectTransformer(@Nullable
 Class<?> targetClass)

JsonToObjectTransformer

public JsonToObjectTransformer(ResolvableType targetType)

Construct an instance based on the provided ResolvableType.

Parameters:

targetType - the ResolvableType to use.

Since:

5.2

JsonToObjectTransformer

public JsonToObjectTransformer(@Nullable
 JsonObjectMapper<?,?> jsonObjectMapper)

JsonToObjectTransformer

public JsonToObjectTransformer(@Nullable
 Class<?> targetClass,
 @Nullable
 JsonObjectMapper<?,?> jsonObjectMapper)

JsonToObjectTransformer

public JsonToObjectTransformer(ResolvableType targetType,
 @Nullable
 JsonObjectMapper<?,?> jsonObjectMapper)

Construct an instance based on the provided ResolvableType and JsonObjectMapper.

Parameters:

targetType - the ResolvableType to use.

jsonObjectMapper - the JsonObjectMapper to use.

Since:

5.2

Method Details

setBeanClassLoader

public void setBeanClassLoader(ClassLoader classLoader)

Specified by:

setBeanClassLoader in interface BeanClassLoaderAware

setValueTypeExpressionString

public void setValueTypeExpressionString(String valueTypeExpressionString)

Configure a SpEL expression to evaluate a ResolvableType to instantiate the payload from the incoming JSON. By default this transformer consults JsonHeaders in the request message. If this expression returns null or ResolvableType building throws a ClassNotFoundException, this transformer falls back to the provided targetType. This logic is present as an expression because JsonHeaders may not have real class values, but rather some type ids which have to be mapped to target classes according some external registry.

Parameters:

valueTypeExpressionString - the SpEL expression to use.

Since:

5.2.6

setValueTypeExpression

public void setValueTypeExpression(Expression valueTypeExpression)

Configure a SpEL Expression to evaluate a ResolvableType to instantiate the payload from the incoming JSON. By default this transformer consults JsonHeaders in the request message. If this expression returns null or ResolvableType building throws a ClassNotFoundException, this transformer falls back to the provided targetType. This logic is present as an expression because JsonHeaders may not have real class values, but rather some type ids which have to be mapped to target classes according some external registry.

Parameters:

valueTypeExpression - the SpEL Expression to use.

Since:

5.2.6

getComponentType

public String getComponentType()

Description copied from class: IntegrationObjectSupport

Subclasses may implement this method to provide component type information.

Specified by:

getComponentType in interface NamedComponent

Overrides:

getComponentType in class IntegrationObjectSupport

onInit

protected void onInit()

Description copied from class: IntegrationObjectSupport

Subclasses may implement this for initialization logic.

Overrides:

onInit in class IntegrationObjectSupport

doTransform

protected Object doTransform(Message<?> message)

Description copied from class: AbstractTransformer

Subclasses must implement this method to provide the transformation logic. If the return value is itself a Message, it will be used as the result. Otherwise, any non-null return value will be used as the payload of the result Message.

Specified by:

doTransform in class AbstractTransformer

Parameters:

message - The message.

Returns:

The result of the transformation.