JSON学习
JSON （JavaScript Object Notation）一种简单的数据格式，比xml更轻巧。 JSON 是 JavaScript 原生格式，这意味着在 JavaScript 中处理 JSON 数据不需要任何特殊的 API 或工具包。JSON的规则很简单： 对象是一个无序的“‘名称/值’对”集合。一个对象以“{”（左括号）开始，“}”（右括号）结束。每个“名称”后跟一个“:”（冒号）；“‘名称/值’ 对”之间使用“,”（逗号）分隔。具体细节参考http://www.json.org/json-zh.html举个简单的例子：js 代码function showJSON() { var user = { "username":"andy", "age":20, "info": { "tel": "123456", "cellphone": "98765"}, "address": [ {"city":"beijing","postcode":"222333"}, {"city":"newyork","postcode":"555666"} ] } alert(user.username); alert(user.age); alert(user.info.cellphone); alert(user.address.city); alert(user.address.postcode); } 这表示一个user对象，拥有username, age, info, address 等属性。同样也可以用JSON来简单的修改数据，修改上面的例子js 代码function showJSON() { var user = { "username":"andy", "age":20, "info": { "tel": "123456", "cellphone": "98765"}, "address": [ {"city":"beijing","postcode":"222333"}, {"city":"newyork","postcode":"555666"} ] } alert(user.username); alert(user.age); alert(user.info.cellphone); alert(user.address.city); alert(user.address.postcode); user.username = "Tom"; alert(user.username); } JSON提供了json.js包，下载http://www.json.org/json.js 后，将其引入然后就可以简单的使用object.toJSONString()转换成JSON数据。js 代码function showCar() { var carr = new Car("Dodge", "Coronet R/T", 1968, "yellow"); alert(carr.toJSONString()); } function Car(make, model, year, color) { this.make=make; this.model=model; this.year=year; this.color=color; } 可以使用eval来转换JSON字符到Objectjs 代码function myEval() { var str = '{ "name": "Violet", "occupation": "character" }'; var obj = eval('(' + str + ')'); alert(obj.toJSONString()); } 或者使用parseJSON()方法js 代码function myEval() { var str = '{ "name": "Violet", "occupation": "character" }'; var obj = str.parseJSON(); alert(obj.toJSONString()); } 下面使用prototype写一个JSON的ajax例子。先写一个servlet (我的是servlet.ajax.JSONTest1.java)就写一句话 java 代码response.getWriter().print("{ \"name\": \"Violet\", \"occupation\": \"character\" }"); 再在页面中写一个ajax的请求js 代码function sendRequest() { var url = "/MyWebApp/JSONTest1"; var mailAjax = new Ajax.Request( url, { method: 'get', onComplete: jsonResponse } ); } function jsonResponse(originalRequest) { alert(originalRequest.responseText); var myobj = originalRequest.responseText.parseJSON(); alert(myobj.name); } prototype-<st1:chsdate w:st="on" isrocdate="False" islunardate="False" day="30" month="12" year="1899">1.5.1</st1:chsdate>.js中提供了JSON的方法，String.evalJSON(), 可以不使用json.js, 修改上面的方法js 代码function jsonResponse(originalRequest) { alert(originalRequest.responseText); var myobj = originalRequest.responseText.evalJSON(true); alert(myobj.name); } JSON还提供了java的jar包 http://www.json.org/java/index.html API也很简单，下面举个例子在javascript中填加请求参数js 代码function sendRequest() { var carr = new Car("Dodge", "Coronet R/T", 1968, "yellow"); var pars = "car=" + carr.toJSONString(); var url = "/MyWebApp/JSONTest1"; var mailAjax = new Ajax.Request( url, { method: 'get', parameters: pars, onComplete: jsonResponse } ); } 使用JSON请求字符串就可以简单的生成JSONObject并进行解析,修改servlet添加JSON的处理(要使用json.jar)java 代码private void doService(HttpServletRequest request, HttpServletResponse response) throws IOException { String s3 = request.getParameter("car"); try { JSONObject jsonObj = new JSONObject(s3); System.out.println(jsonObj.getString("model")); System.out.println(jsonObj.getInt("year")); } catch (JSONException e) { e.printStackTrace(); } response.getWriter().print("{ \"name\": \"Violet\", \"occupation\": \"character\" }"); } 同样可以使用JSONObject生成JSON字符串，修改servletjava 代码private void doService(HttpServletRequest request, HttpServletResponse response) throws IOException { String s3 = request.getParameter("car"); try { JSONObject jsonObj = new JSONObject(s3); System.out.println(jsonObj.getString("model")); System.out.println(jsonObj.getInt("year")); } catch (JSONException e) { e.printStackTrace(); } JSONObject resultJSON = new JSONObject(); try { resultJSON.append("name", "Violet") .append("occupation", "developer") .append("age", new Integer(22)); System.out.println(resultJSON.toString()); } catch (JSONException e) { e.printStackTrace(); } response.getWriter().print(resultJSON.toString()); } js 代码function jsonResponse(originalRequest) { alert(originalRequest.responseText); var myobj = originalRequest.responseText.evalJSON(true); alert(myobj.name); alert(myobj.age); } 参考
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