Mule how to map Json values from payload to flow variables - mule

Question

I have a JDBC COnnector which retrieves values from the database and I have mapped them from object to JSON. Now I want to extract specific values from the json to flow variables. When I try to log #[message.payload], I get the full payload in the log which is in JSON format. However when I try to choose an attribute (eg. testattribute in json) #[message.payload.testattribute], I get mule expression error. How do I refer to the json values?

Answer 1

Once the payload is a JSON string, you can't extract anything from it anymore with an expression.
So either:
use MEL to extract the values into flow variables prior to convert the payload into JSON,
transform the JSON payload to either POJOs or Map/Lists, use MEL to extract the values into flow variables, and re-transform the payload back to JSON.

Answer 2

If your requirement is to get the values from json data you can use a simple MEL expression like
#[json:<name of the node>]
For example if you have an sample json data like this
{
"token" : 123,
"id" : 456,
"email" : "abc#abc.com",
"status" : "Success"
}
and if you want get the id from the data just use the below simple MEL.
#[json:'id']

Answer 3

Mule has JSON-to-Object transformer which can be used to get JSON elements.
For example if your JSON is following :-
{
"token" : 123,
"id" : 456,
"email" : "abc#abc.com",
"status" : "Success"
}
Now, to extract the elements, you need to use :-
<json:json-to-object-transformer returnClass="java.lang.Object" doc:name="JSON to Object" />
And then can extract like :- #[message.payload.email] or #[message.payload.status]

Answer 4

Use components as follow
Object - String
Object - JSON
then u can directly extract using value using json expression as #{json:email},
in below xml i have used the variable component to set the #{json:email} in "var1" flow variable for usability
Note: json expression is even available in studio version of 5.x
<object-to-string-transformer doc:name="Object to String"/>
<json:object-to-json-transformer doc:name="Object to JSON"/>
<set-variable variableName="var1" value="#[json:email]" doc:name="Variable"/>