Gson.toJson方法對於傳入的空對象返回默認爲「」,設置serializeNulls爲true,則返回「null」.java
再寫入response流時,對傳入的對象作爲空判斷,爲空則返回「{}」。jquery
HttpServletResponse response = getResponse(); response.setHeader("Content-Type", "application/json;charset=UTF-8"); try { response.getWriter().write(o == null ? "{}" : gson.toJson(o)); response.getWriter().flush(); } catch (IOException e) { e.printStackTrace(); }
頁面使用jquery判斷是否爲空對象:json
$.isEmptyObject(data)//data爲傳入的json對象。app