How to maintain the order of a JSONObject

Question

I am using a JSONObject in order to remove a certin attribute I don\'t need in a JSON String:

JSONObject jsonObject = new JSONObject(jsonString);
jsonObject.         


        

Answer 1

You can use Jsckson library in case to maintain the order of Json keys. It internally uses LinkedHashMap ( ordered ).

import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;

The code to remove a field, the removed JsonToken could itself be read if required.

  String jsonString = "{\"name\":\"abc\",\"address\":\"add\",\"data\":[\"some 1\",\"some 2\",\"some3 3\"],\"age\":12,\"position\":8810.21}";
  ObjectMapper mapper = new ObjectMapper();
  JsonNode node = mapper.readTree(jsonString);
  System.out.println("In original order:"+node.toString());
  JsonToken removedToken = ((ObjectNode) node).remove("address").asToken();
  System.out.println("Aft removal order:"+node.toString());

ObjectNode implementation uses a LinkedHashMap, which maintains the insertion order:

 public ObjectNode(JsonNodeFactory nc) {
   super(nc);
   _children = new LinkedHashMap();
 }