JSONArray和JSONObject的简单使用
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一、为什么要使用JSONArray和JSONObject
1、后台 --》前台 能够把java对象和集合转化成json字符串格式,这样在前台的ajax方法中能够直接转化成json对象使用 ,从后台向前台传值
2、前台 --》使用JSON.stringify(mdses)方法把js对象,数组。转化成json字符串 ,后台使用JSONArray或JSONObject 转化成 java对象或集合
有助于前端參数传递到后端。和后端取值y
3、json如今以成为大多传输数据的载体
二、后台解析前台ajax提交数据,使用较少一般都把list 或map转化为json形式的字符串传值到前台的ajax中:
//依据接收的json字符串来解析字符串中所包括的数据和数据对象 @Test public void parsJsonFromFront(){ //接收到的json String result = "[{\"username\": \"your name\", \"user_json\": {\"username\": \"your name\", \"nickname\": \"your nickname\"}}]"; //依据字符串陈 //依据字符串生成JSON对象 //假设是数组的形式 就使用 JSONArray.fromObject(result) 转化为JSONArray 对象 //假设是json对象 就是使用JSONObject.fromObject(result) 转化为JSONObject 对象 JSONArray resultArray = JSONArray.fromObject(result); JSONObject jsonObject = resultArray.getJSONObject(0); JSONObject user_json = jsonObject.getJSONObject("user_json"); //依据key值取值 String username = user_json.getString("username"); String nickname = user_json.getString("nickname"); System.out.println("username =" + username + ":" + "nickname = " + nickname); //console : username =your name:nickname = your nickname }
三 、后台转化list 或map转化为json形式的字符串传值到前台的ajax中
user bean
public class User { private String name; private Adress adress; private List<String> students; public String getName() { return name; } public void setName(String name) { this.name = name; } public Adress getAdress() { return adress; } public void setAdress(Adress adress) { this.adress = adress; } public List<String> getStudents() { return students; } public void setStudents(List<String> students) { this.students = students; } public User(String name, Adress adress, List<String> students) { super(); this.name = name; this.adress = adress; this.students = students; } public User() { super(); } }
public class Adress { private String streetName; private String district; public String getStreetName() { return streetName; } public void setStreetName(String streetName) { this.streetName = streetName; } public String getDistrict() { return district; } public void setDistrict(String district) { this.district = district; } public Adress(String streetName, String district) { super(); this.streetName = streetName; this.district = district; } public Adress() { super(); // TODO Auto-generated constructor stub } }
1)bean to json
@Test public void beanToJson(){ List list = new ArrayList(); list.add( "xiaowang" ); list.add( "xiaohua" ); Adress adress = new Adress("streetName", "district"); JSONObject jsonObject = JSONObject.fromObject(new User("name", adress, list)); System.out.println(jsonObject.toString()); //console :{"adress":{"district":"district","streetName":"streetName"},"name":"name","students":["xiaowang","xiaohua"]} }
2)
@Test public void list2Json(){ List list = new ArrayList(); list.add( "first" ); list.add( "second" ); JSONArray jsonArray = JSONArray.fromObject(list); System.out.println(jsonArray.toString()); } public Map getMap(){ //声明一个Hash对象并加入数据 Map params = new HashMap(); params.put("username", "username"); params.put("user_json", "user"); return params; } @Test public void map2Json(){ Map map = getMap(); Map map1 = getMap(); List list = new ArrayList(); list.add(map); list.add(map1); JSONArray jsonArray = JSONArray.fromObject(list); System.out.println("jsonArray--->" + jsonArray.toString()); JSONArray jsonArray1 = JSONArray.fromObject(map); System.out.println("jsonArray1--->" + jsonArray1.toString()); }
完整:
public class SimpleExample { @Test public void list2Json(){ List list = new ArrayList(); list.add( "first" ); list.add( "second" ); JSONArray jsonArray = JSONArray.fromObject(list); System.out.println(jsonArray.toString()); } public Map getMap(){ //声明一个Hash对象并加入数据 Map params = new HashMap(); params.put("username", "username"); params.put("user_json", "user"); return params; } @Test public void map2Json(){ Map map = getMap(); Map map1 = getMap(); List list = new ArrayList(); list.add(map); list.add(map1); JSONArray jsonArray = JSONArray.fromObject(list); System.out.println("jsonArray--->" + jsonArray.toString()); JSONArray jsonArray1 = JSONArray.fromObject(map); System.out.println("jsonArray1--->" + jsonArray1.toString()); } //依据接收的json字符串来解析字符串中所包括的数据和数据对象 @Test public void parsJsonFromFront(){ //接收到的json String result = "[{\"username\": \"your name\", \"user_json\": {\"username\": \"your name\", \"nickname\": \"your nickname\"}}]"; //依据字符串陈 //依据字符串生成JSON对象 //假设是数组的形式 就使用 JSONArray.fromObject(result) 转化为JSONArray 对象 //假设是json对象 就是使用JSONObject.fromObject(result) 转化为JSONObject 对象 JSONArray resultArray = JSONArray.fromObject(result); JSONObject jsonObject = resultArray.getJSONObject(0); JSONObject user_json = jsonObject.getJSONObject("user_json"); //依据key值取值 String username = user_json.getString("username"); String nickname = user_json.getString("nickname"); System.out.println("username =" + username + ":" + "nickname = " + nickname); //console : username =your name:nickname = your nickname } @Test public void beanToJson(){ List list = new ArrayList(); list.add( "xiaowang" ); list.add( "xiaohua" ); Adress adress = new Adress("streetName", "district"); JSONObject jsonObject = JSONObject.fromObject(new User("name", adress, list)); System.out.println(jsonObject.toString()); //console :{"adress":{"district":"district","streetName":"streetName"},"name":"name","students":["xiaowang","xiaohua"]} } }
相关依赖jar下载:http://download.csdn.net/detail/hao007cn/8995465
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