使用gson(一)

1、数组和json的转换

 1 package com.test.gson;
 2 import com.google.gson.Gson;
 3 public class ArrayToJson {
 4
 5     public static void main(String[] args) {
 6         // TODO Auto-generated method stub
 7         int[] numbers = {1,2,3,4,5,6,7,8,9};
 8         String[] days = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
 9
10         Gson gson = new Gson();
11
12         String numbersJson = gson.toJson(numbers);
13         System.out.println("numbersJson=" + numbersJson);
14
15         int[] nums = gson.fromJson(numbersJson, int[].class);
16         for(int i=0; i<nums.length ; i++){
17             System.out.println(nums[i]);
18         }
19         String daysJson = gson.toJson(days);
20         System.out.println("daysJson=" + daysJson);
21
22         String[] weekDays = gson.fromJson(daysJson, String[].class);
23         for(int j=0; j<weekDays.length; j++){
24             System.out.println(weekDays[j]);
25         }
26     }
27
28 }

2、对象和json的转换

 1 package com.test.gson;
 2
 3 import com.google.gson.Gson;
 4
 5 public class StudentToJson {
 6
 7     public static void main(String[] args) {
 8         // TODO Auto-generated method stub
 9         Student student = new Student(1001,"gulu","beijing");
10         Gson gson = new Gson();
11
12         String studentJson = gson.toJson(student);
13         System.out.println("studentJson=" + studentJson);
14
15         Student stu = gson.fromJson(studentJson, Student.class);
16         System.out.println(stu.toString());
17         System.out.println(stu.getId());
18         System.out.println(stu.getName());
19         System.out.println(stu.getAddress());
20     }
21
22 }

3、List和json的转换

 1 package com.test.gson;
 2
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 import java.lang.reflect.Type;
 6
 7 import com.google.gson.Gson;
 8 import com.google.gson.reflect.TypeToken;
 9
10 public class CollectionToJson {
11
12     public static void main(String[] args) {
13         // TODO Auto-generated method stub
14         List<String> names = new ArrayList<String>();
15         names.add("Alice");
16         names.add("Bob");
17         names.add("Carol");
18         names.add("Mallory");
19
20         Gson gson = new Gson();
21
22         String jsonNames = gson.toJson(names);
23         System.out.println("jsonNames="+jsonNames);
24
25         Student a = new Student(1,"zhangsan","beijing");
26         Student b = new Student(2,"wangwu","nanjing");
27         Student c = new Student(3,"lisi","guangzhou");
28         Student d = new Student(4,"wangba","shanghai");
29
30         List<Student> students = new ArrayList<Student>();
31         students.add(a);
32         students.add(b);
33         students.add(c);
34         students.add(d);
35
36         String jsonStudents = gson.toJson(students);
37         System.out.println("jsonStudents="+jsonStudents);
38
39         Type type = new TypeToken<List<Student>>(){}.getType();
40         List<Student> studentList = gson.fromJson(jsonStudents, type);
41         for(Student student : studentList){
42             System.out.println(student.getName());
43         }
44     }
45
46 }

4、map和json的转换

 1 package com.test.gson;
 2
 3 import java.lang.reflect.Type;
 4 import java.util.HashMap;
 5 import java.util.Map;
 6
 7 import com.google.gson.Gson;
 8 import com.google.gson.reflect.TypeToken;
 9
10 public class MapToJson {
11
12     public static void main(String[] args) {
13         // TODO Auto-generated method stub
14         Map<String, String> colours = new HashMap<String,String>();
15         colours.put("black", "#000000");
16         colours.put("red", "#ff0000");
17         colours.put("green", "#00ff00");
18         colours.put("blue", "#0000ff");
19
20         Gson gson = new Gson();
21         String mapJson = gson.toJson(colours);
22         System.out.println("gson="+mapJson);
23
24         Type type = new TypeToken<Map<String,String>>(){}.getType();
25
26         Map<String,String> map = gson.fromJson(mapJson, type);
27         for(String key : map.keySet()){
28             System.out.println("map.get=" + map.get(key));
29         }
30     }
31
32 }