How to retrieve the value of key of json input in the string variable in webmethods flow service

I have json input such that {“firstname”:“test”,“Postal_code”:“N2J5C4”} . I am looking to find value of Postal_code field which i need to pass into JDBC adapter.
Can it be done without java service.

Yes. You have to convert the JSON string to a document using the services from WmPublic. Then you’ll be able to access all the fields in a very comfortable way. This might be not the most efficient way to do this in the terms of CPU and memory, but it’s optimal wrt. the development time.