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":"cxl"},{"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","username":"cxl"},{"password":"1234","username":"lhl"}],"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":"cxl"},{"password":"1234","username":"lhl"}],"u":{"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=# οnclick=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 }