Java tutorial
//package com.java2s; import java.util.Map; import org.json.JSONException; import org.json.JSONObject; public class Main { public static String Json2Str(Map<String, Object> info) { String result = ""; if (info != null) { try { JSONObject json = new JSONObject(); for (Map.Entry<String, Object> e : info.entrySet()) { String key = e.getKey(); if (json.isNull(key)) { json.put(key, null); } else { json.put(key, json.get(key)); } } result = json.toString(); } catch (JSONException e) { e.printStackTrace(); } } return result; } }