ObjectMapper class can be used to generate a json string from a Map.

Example

Following example is using ObjectMapper class to generate a JSON string from a Map Object.

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.boon.json.JsonFactory;
import org.boon.json.ObjectMapper;

public class BoonTester {
   public static void main(String args[]){
      ObjectMapper mapper = JsonFactory.create();      
      Map<String, String> student = new HashMap<>();
      student.put("Name", "Mahesh");
      student.put("RollNo", "21");
      
      Map<String, String> student1 = new HashMap<>();
      student1.put("Name", "Suresh");
      student1.put("RollNo", "22");
      
      List<Map<String,String>> studentList = new ArrayList<>();
      studentList.add(student);
      studentList.add(student1);
      
      Map<String, List> studentMap = new HashMap<String, List>();
      studentMap.put("students", studentList);
      
      String jsonString = mapper.writeValueAsString(studentMap);
      System.out.println(jsonString);
   }
}

Output

When you execute the above code, you should see the following output −

{"students":[{"RollNo":"21","Name":"Mahesh"},{"RollNo":"22","Name":"Suresh"}]}