1 package utils;
2
3 import java.util.ArrayList;
4 import java.util.List;
5 import com.google.gson.Gson;
6 import com.google.gson.JsonObject;
7 import com.google.gson.reflect.TypeToken;
8 import java.lang.reflect.Type;
9 import bean.User;
10 import net.sf.json.JSONArray;
11
12 public class GsonUtil {
13
14 /**
15 * 将json数据串转换成对象数据
16 *
17 * @param json
18 * @param cls
19 * @return
20 * @throws Exception
21 */
22 public static <T> T fromJson(String json, Class<T> cls) throws Exception {
23 T obj = null;
24 Gson gson = new Gson();
25 obj = cls.newInstance();
26 obj = gson.fromJson(json, cls);
27 return obj;
28 }
29
30 /**
31 * 将对象转化成Json 数据串
32 *
33 * @param obj
34 * @return
35 */
36 public static String objToJson(Object obj) {
37 return new Gson().toJson(obj);
38 }
39
40 /**
41 * 将List Json数据串转换成List集合
42 *
43 * @param json
44 * @param clas
45 * @return
46 */
47 public static <T> ArrayList<T> jsonToArrayList(String json, Class<T> cls) {
48 Type type = new TypeToken<ArrayList<JsonObject>>() {
49 }.getType();
50 ArrayList<JsonObject> jsonObjects = new Gson().fromJson(json, type);
51
52 ArrayList<T> arrayList = new ArrayList<>();
53 for (JsonObject jsonObject : jsonObjects) {
54 arrayList.add(new Gson().fromJson(jsonObject, cls));
55 }
56 return arrayList;
57 }
58
59 /**
60 * 将List集合转化成Json数据串
61 *
62 * @param list
63 * @return
64 */
65 public static String listToJson(Object list) {
66 JSONArray jsonArray = JSONArray.fromObject(list);
67 return jsonArray.toString();
68 }
69
70 /**
71 * test
72 * 测试
73 * @param args
74 */
75 public static void main(String[] args) {
76 try {
77 User u1 = new User();
78 u1.setUid(100000);
79 u1.setAddress("sasassdasd");
80 u1.setAge(25);
81 u1.setEmail("2515@qq.com");
82 u1.setName("sai");
83 String string = objToJson(u1);
84 User u2 = new User();
85 User u3 = new User();
86 u3.setUid(100000);
87 u3.setAddress("sasassdasd");
88 u3.setAge(25);
89 u3.setEmail("25175@qq.com");
90 u3.setName("sai");
91 List<User> uList = new ArrayList<User>();
92 uList.add(u1);
93 uList.add(u3);
94 String s2 = listToJson(uList);
95
96 List<User> uList1 = new ArrayList<User>();
97 uList1 = jsonToArrayList(s2, User.class);
98
99 for (User user : uList1) {
100 System.out.println(user.toString());
101 }
102
103 u2 = fromJson(string, User.class);
104 System.out.println(u2.toString());
105 } catch (Exception e) {
106 // TODO Auto-generated catch block
107 e.printStackTrace();
108 }
109 }
110
111 }
