java解析json的一種方法

package com.hanchao.web;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
/***********************
 * java解析json
 * @author：han  
 * @version：1.0      
 * @created：2013-8-28  
 ***********************
 */
public class TestJson {
    public static void main(String[] args) {
                                         
        String json = "{'id':1," +
                        "'username':{'tom':'tom','jerry':'jerry'}," +
                        "'address':[{'us':'usa','cancada':'canada'},{'chi':'china','aus':'aus'}]}";
                                         
        JSONObject jo = JSONObject.fromObject(json);
        System.err.println("1--:" + jo.get("id"));
                                         
        JSONObject uObject = jo.getJSONObject("username");
        System.out.println("2--username:" + uObject);
        System.out.println("2--username:" + uObject.get("tom"));
                                         
        JSONArray addressArray = jo.getJSONArray("address");
        System.out.println("3--:" + addressArray.getJSONObject(0));
        System.out.println("3--:" + addressArray.getJSONObject(0).get("us"));
        System.out.println("3--:" + addressArray.getJSONObject(1).get("chi"));
    }
}

結果：

1--:1

2--username:{"tom":"tom","jerry":"jerry"}

2--username:tom

3--:{"us":"usa","cancada":"canada"}

3--:usa

3--:china

============對象轉爲JSON對象---------------

Map<String, Object> map = new HashMap<String, Object>();
map.put("id", 1);
map.put("username", "hanchao");
map.put("password", 123L);
String toJson = JSONObject.fromObject(map).toString();
System.out.println("toJSON:" + toJson);
JSONObject jo1 = JSONObject.fromObject(toJson);
System.out.println("id:" + jo1.getInt("id") + ", username:" + jo1.getString("username") + ", password:" + jo1.getString("password"));
//2014-04-03-把List集合轉爲JSon數組--------------------------------------------
//方法一：
List<User> list = new ArrayList<User>();
User u1 = new User();
u1.setId(1);
u1.setUsername("u1");
u1.setPassword("p1");
User u2 = new User();
u2.setId(2);
u2.setUsername("u2");
u2.setPassword("p2");
list.add(u1);
list.add(u2);
String resultJson = JSONArray.fromObject(list).toString();
System.out.println(" ========= : " + resultJson);
//方法二：
JSONArray array = new JSONArray();
for(User user : list) {
    JSONObject obj = new JSONObject();
    obj.put("username", user.getUsername());
    obj.put("id", user.getId());
    obj.put("password", user.getPassword());
    array.add(obj);
}
String resultJSON2 = array.toString();
System.out.println(" ========= : " + resultJSON2);