MULE: JSON TO OBJECT

HANDLING UNRECOGNIZED FIELD

JSON SUPPORT REFERENCE• JSON, short for JavaScript Object Notation, is a lightweight data

interchange format. • Mule supports binding JSON data to objects and marshalling Java

object to JSON using the Jackson Framework.• JSON transformers have been added in Studio to make it easy to

work with JSON encoded messages.

JSON BINDINGS (1/2)• Jackson uses annotations to describe how data is mapped to a Java

object model.• For example an JSON file that describes a person:

{ "id": 1, "name": "Max"}

JSON BINDINGS (2/2)• @JsonAutoDetect maps directly the field member names to JSON

field names.package com.mulesoft.learning;

import org.codehaus.jackson.annotate.JsonAutoDetect;

@JsonAutoDetectpublic class Person {

private String id; private String name; //getter-setter}

JSON TO OBJECT: DEMO - DESIGN• HTTP: an inbound endpoint for posting the JSON data.• JSON to Object: transforming the JSON data to a Java object.• Logger: displaying the log.

JSON TO OBJECT: DEMO - XML CONFIG• Two-way editing between graphical and XML views.

<flow name="jsonToObjectFlow"> <http:listener config-ref="HTTP_Listener_Configuration" path="/" doc:name="HTTP"/> <json:json-to-object-transformer returnClass="com.mulesoft.learning.Person" doc:name="JSON to Object"/> <logger message="#[payload]" level="INFO" doc:name="Logger"/></flow>

JSON TO OBJECT: TESTING (1/2)• Use a REST Client, e.g.: Postman, for posting the JSON data.

JSON TO OBJECT: TESTING (2/2)• Posting the JSON data with an unrecognized field: Failed!

JSON TO OBJECT: ISSUE• JSON to Object Transformer failed to transform an JSON data with

unrecognized field.• Root Exception stack trace:

org.codehaus.jackson.map.exc.UnrecognizedPropertyException: Unrecognized field "type" (Class com.mulesoft.learning.Person), not marked as ignorable.

• How to easily adapt to change if this issue happens?

JSON TO OBJECT: SOLUTION• Ignore unrecognized field.

package com.mulesoft.learning;

import org.codehaus.jackson.annotate.JsonAutoDetect;import org.codehaus.jackson.annotate.JsonIgnoreProperties;

@JsonAutoDetect@JsonIgnoreProperties(ignoreUnknown=true)public class Person {

private String id; private String name; //getter-setter}

JSON TO OBJECT: FINAL TESTING• Posting the JSON data with an unrecognized field: Success!

SUMMARY• JSON is natively supported in Mule.• JSON data can be bind automatically to Java object.• Unrecognized field can be handled by Jackson Framework.

RESOURCES• https://

docs.mulesoft.com/mule-user-guide/v/3.8/json-module-reference• https://

docs.mulesoft.com/mule-user-guide/v/3.8/native-support-for-json