JSON与JAVA数据的转换

JavaBean,List,Map转成json格式

JS解析json数据（如何将json字符串转化为数组）

需要四個包：

commons-beanutils-1.8.3.jar

commons-lang-2.3.jar

ezmorph-1.0.6.jar

json-lib-2.4-jdk15.jar

普通JavaBean(以User为例)转成json格式
1.转成JSONArray类型
User user = new User();
user.setUsername("cxl");
user.setPassword("1234");
JSONArray json = JSONArray.fromObject(user);
System.out.println(json);//[{"password":"1234","username":"cxl"}]
response.getWriter().print(json.toString());
在js文件取数据
$.getJSON("http://localhost:8080/jQueryDemo/servlet/UserServlet",null,function(data) {
alert(data[0].username);
alert(data[0].password);
});
2.转成JSONObject类型
JSONObject jsonObj = JSONObject.fromObject(user);
System.out.println(jsonObj);//{"password":"1234","username":"cxl"}
response.getWriter().print(jsonObj);
在js文件取数据
alert(data.username);
alert(data.password);

List转成json格式
List<User> users = new ArrayList<User>();
User user = new User();
user.setUsername("cxl");
user.setPassword("1234");
User u = new User();
u.setUsername("lhl");
u.setPassword("1234");
users.add(user);
users.add(u);
1.转成JSONArray类型
JSONArray json = JSONArray.fromObject(users);
System.out.println(json.toString());
//[{"password":"1234","username":"cxl"},{"password":"1234","username":"lhl"}]
response.getWriter().print(json.toString());
js中取数据：alert(alert(data[0].username));
2.转成JSONObject类型
不可直接使用JSONObject jsonObj = JSONObject.fromObject(users);
可通过下列方式
JSONObject jsonObj = new JSONObject();
jsonObj.put("users",users);
jsonObj.put("u",u);
System.out.println(jsonObj);
{"users":[{"password":"1234","username":"lhl"}],
"u":{"password":"1234","username":"lhl"}}
response.getWriter().print(jsonObj);
js中取数据：alert(data.users[0].username);
alert(data.u[0].username);

Map转成json格式
Map<String,Object> map = new HashMap<String,Object>();
map.put("users",users);
map.put("u",u);
1.转成JSONArray类型
JSONArray json = JSONArray.fromObject(map);
System.out.println(json.toString());//
[{"users":[{"password":"1234","u":{"password":"1234","username":"lhl"}}]
response.getWriter().print(json.toString);
js中取数据：alert(data[0].users[0].username);
2.转成JSONObject类型
JSONObject json = JSONObject.fromObject(map);
System.out.println(json);//
{"user":[{"password":"1234","username":"lhl"}}
response.getWriter().print(json);
js中取数据：alert(data.user[0].username);

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

var t="{'firstName': 'cyra','lastName': 'richardson','address': { 'streetAddress': '1 Microsoft way','city': 'Redmond','state': 'WA','postalCode': 98052 },'phoneNumbers': [ '425-777-7777','206-777-7777' ] }";
10     var jsonobj=eval('('+t+')');
11     alert(jsonobj.firstName);
12     alert(jsonobj.lastName);
13 
14 
15 var t2="[{name:'zhangsan',age:'24'},{name:'lisi',age:'30'},{name:'wangwu',age:'16'},{name:'tianqi',age:'7'}] ";
16 var myobj=eval(t2);
17 for(var i=0;i<myobj.length;i++){
18    alert(myobj[i].name);
19    alert(myobj[i].age);
20 }
21 
22 var t3="[['<a href=# onclick=openLink(14113295100,社旗县国税局桥头税务所,14113295100,d6d223892dc94f5bb501d4408a68333d,swjg_dm);>14113295100</a>','社旗县国税局桥头税务所','社旗县城郊乡长江路西段']]";
23 //通过eval() 函数可以将JSON字符串转化为对象
24 var obj = eval(t3);
25 for(var i=0;i<obj.length;i++){
26    for(var j=0;j<obj[i].length;j++){
27 alert(obj[i][j]);
28    }
29 
30 }