I am getting the above error, due to a problem with Jackson attempting to deserialize my POJO.
I've debugged the code and it returns false within Jackson's ObjectMapper:
public boolean canRead(Type type, Class<?> contextClass, MediaType mediaType) {
JavaType javaType = getJavaType(type, contextClass);
return (this.objectMapper.canDeserialize(javaType) && canRead(mediaType));
}
this.objectMapper.canDeserialize(javaType) returns false which causes the error
My Controller is as follows:
@Controller
public class CancelController {
@Autowired
private CancelService cancelService;
@RequestMapping( value="/thing/cancel", method=RequestMethod.POST, consumes="application/json" )
public @ResponseBody CancelThingResponseDTO cancelThing(@RequestBody CancelRequestDTO cancelThingRequest) {
return cancelService.cancelThing(cancelThingRequest);
}
My CancelRequestDTO implements Serializable:
public class CancelRequestDTO implements Serializable{
/**
* Default serialization ID
*/
private static final long serialVersionUID = 1L;
/**
* Reason code associated with the request
*/
private final String reasonCode;
/**
* Identifier of the entity associated with the request
*/
private final EntityIdentifier entityIdentifier;
/**
* Default constructor
*
* @param reasonCode Reason code associated with the request
* @param entityIdentifier Identifier of the entity associated with the request
*/
public CancelRequestDTO(String reasonCode, EntityIdentifier entityIdentifier) {
super();
this.reasonCode = reasonCode;
this.entityIdentifier = entityIdentifier;
}
/**
* @return Returns the reasonCode.
*/
public String getReasonCode() {
return reasonCode;
}
/**
* @return Returns the entityIdentifier.
*/
public EntityIdentifier getEntityIdentifier() {
return entityIdentifier;
}
}
My Spring configuration is as follow:
<!-- DispatcherServlet Context: defines this servlet's request-processing
infrastructure -->
<!-- Enables the Spring MVC @Controller programming model -->
<mvc:annotation-driven />
<!-- Scan for stereotype annotations -->
<context:component-scan base-package="com.cancel.web.controller" />
<bean id="viewNameTranslator"
class="org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator" />
<bean class="org.springframework.web.servlet.view.BeanNameViewResolver" />
<bean id="jsonView"
class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" >
<property name="contentType" value="application/json;charset=UTF-8"/>
</bean>
<!-- Register JSON Converter for RESTful Web Service -->
<bean
class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="messageConverters">
<list>
<bean
class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
</bean>
</list>
</property>
</bean>
Anyone know what might be causing this deserialization issue?
Thanks
Caused by my DTO not having a default constructor with setters! So looks like an inaccurate Exception from Jackson
对于仍然面临这个问题的人,你不能在一个类中有两个@JsonBackReference
,像这样添加一个引用@JsonBackReference(value = "secondParent")
也将相同的值添加到@JsonManagedReference(value ="secondParent")
在父类中。
I have always done this using the ContentNegotiatingViewResolver. It seems that it is not understanding the content type that you are passing it. This is the configuration that I typically use for doing what you are trying to do:
<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
<property name="order" value="1" />
<property name="contentNegotiationManager">
<bean class="org.springframework.web.accept.ContentNegotiationManager">
<constructor-arg>
<bean class="org.springframework.web.accept.PathExtensionContentNegotiationStrategy">
<constructor-arg>
<map>
<entry key="json" value="application/json" />
<entry key="xml" value="application/xml" />
</map>
</constructor-arg>
</bean>
</constructor-arg>
</bean>
</property>
<property name="defaultViews">
<list>
<bean class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" />
<bean class="org.springframework.web.servlet.view.xml.MarshallingView">
<constructor-arg>
<bean class="org.springframework.oxm.xstream.XStreamMarshaller">
<property name="autodetectAnnotations" value="true" />
</bean>
</constructor-arg>
</bean>
</list>
</property>
</bean>
This video goes through doing exactly what you are trying to do with consuming the service through jQuery in the UI:
http://pluralsight.com/training/Courses/TableOfContents/springmvc-intro
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