Getting error while parsing JSON in Mule - mule-studio

Question

I am making a webservice call from Mule to another system using mule anypoint studio. The call happens fine and I do see a message returned from the external system. Now i am trying to pass an input for that webservice call using JSON string. This value would be logged on the external system which we are making the call to. I am using Datamapper for that and selecting the JSON file in the data mapper configuration. The map is happening without any error but when I am invoking the mule flow(via http connector).
I see this error on console
Unexpected character ('N' (code 78)): was expecting double-quote to
start field name at [Source: java.io.InputStreamReader#687aae57;
line: 1, column: 3] ERROR 2016-08-23 18:42:44,405 [WatchDog_0]
org.jetel.graph.runtime.SingleThreadWatchDog: Error details:
org.jetel.exception.JetelRuntimeException: Component [JSON
READER:JSON_READER0] finished with status ERROR.
org.codehaus.jackson.JsonParseException: Unexpected character ('N' (code 78)): was expecting double-quote to start field name
Root Exception stack trace:
org.codehaus.jackson.JsonParseException: Unexpected character ('N' (code 78)): was expecting double-quote to start field name
at [Source: java.io.InputStreamReader
at [Source: java.io.InputStreamReader#
I thought the problem is with the JSON file but not able to figure out where.. My JSON file looks like
{"receiveMessageFromMule":"Invocation Message from Mule"}
Could anyone help ?

Answer 1

#Angel, according to the error the JSON data received with unquoted field names (doesn't have the double quotes,", for field names). You need to enable jackson mapper to handle the unquoted field names, this can be done by adding the JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES to the ObjectMapper configuration.
You can customize the JSON transformer by injecting the custom ObjectMapper using spring in mule. Below is the code snippet for reference
<spring:bean id="jacksonObjectMapper" class="org.codehaus.jackson.map.ObjectMapper" />
<spring:bean
class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<spring:property name="targetObject" ref="jacksonObjectMapper" />
<spring:property name="targetMethod" value="configure" />
<spring:property name="arguments">
<spring:list>
<spring:value>ALLOW_UNQUOTED_FIELD_NAMES</spring:value>
<spring:value>true</spring:value>
</spring:list>
</spring:property>
</spring:bean>
<json:object-to-json-transformer mapper-ref="jacksonObjectMapper" />
Hope this helps