JSON与null

org.json.JSONObject orgJSON = new org.json.JSONObject();// The method put(String, Collection) is ambiguous for the type JSONObject//orgJSON.put("null", null);net.sf.json.JSONObject netJSON = new net.sf.json.JSONObject();netJSON.put("null", null);System.out.println("netJSON" + netJSON); // 控制台输出 : netJSON{}