How to fetch value from database which is in json format using spring?

public String getChildLocation(String pk_location_id){

ObjectMapper mapper = new ObjectMapper(); 

JsonNode node = mapper.createObjectNode();

ArrayNode objNode = mapper.createArrayNode();

try {

Query query = em.createQuery("Select js.tree_node FROM JsonTreeStructure js where js.id=:id").setParameter("id",Long.parseLong(pk_location_id));

String result = query.getSingleResult().toString();

System.out.println("result:"+result);

node =mapper.readTree(result);  

objNode = (ArrayNode) node.path("children");

return "objNode"+objNode;

}catch(Exception e){

System.out.println("EXCeption:"+e.getMessage());

return e.getMessage();

}

//return "....";

}

In url if I pass id as 1 (http://localhost:8088/microservice/getChildLocation/1)

I am getting following result:

objNode[{"text":"India","value":2,"disabled":true,"children":[]},{"text":"Exceego","value":3,"children":[{"text":"hubli1","value":4,"children":[]}]}]

But I want to fetch the children of value 3

(http://localhost:8088/microservice/getChildLocation/3), if I pass 3 in the path I am getting exception as follows :

No entity found for query.

Can anyone please provide solution for this.

Thanks & Regards

Shilpa Kulkarni

Query query = em.createQuery("Select js.tree_node FROM JsonTreeStructure js where js.id=:id").setParameter("id",Long.parseLong(pk_location_id));

Because the domain is as follows:

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.Table;

@Entity

@Table(name = "jsonTree")

public class JsonTreeStructure {

@Id

@GeneratedValue(strategy = GenerationType.AUTO)

private Long id;

@Column(name="location_tree",columnDefinition="LONGTEXT")

private String tree_node;

public Long getId() {

return id;

}

public void setId(Long id) {

this.id = id;

}

public String getTree_node() {

return tree_node;

}

public void setTree_node(String tree_node) {

this.tree_node = tree_node;

}

}

So, in the query I want to pass the tree_node value as 3. How to write query for that?