JSONObject、 JsonObject、阿里fastJson、谷歌gson区别

JSON：JavaScript Object Notation Java对象表示法

Java中并没有内置的 JSON 解析，需要使用第三方类库。常用的类库如下

一、Gson ： 古河开发的JSON 库

二、FastJson ：阿里巴巴的JSON 库

三、JackSon ： 社区十分活跃

JSONObject 是json 对象，一个键对应一个值，例如： {“key”:"value"}

一、com.alibaba.fastjson.JsonObject（参考）

1.添加fastJson依赖

 <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.58</version>
</dependency>

2.将 List 对象转换为 Json 格式的String

 List<User> users= findAllUser();

 String str = JSONObject.toJSONString(users);

3.将 Map 对象转换为 JsonObject

 Map<String,Object> map = new HashMap();
        map.put("name","zhangsan");
        map.put("age","15");
JSONObject jsonObject = new JSONObject(map);

4.将Map 转换为 Json 格式的String 字符串

  String jsonStr = JSON.toJSONString(map);

5.将 json 格式的String 字符串转换为 Map 

 String jsonStr = "{\"name\":\"zhangsan\",\"age\":\"15\"}";

 JSONObject  jsonObject = JSONObject.parseObject(jsonStr);

 Map<String,Object> map = jsonObject;

6. 将 json 格式的字符串转换为 JsonObject

String jsonStr = "{\"name\":\"zhangsan\",\"age\":\"15\"}";

JSONObject jsonObject = JSON.parseObject(jsonStr);

7. 将 json字符串转换为 Java对象

 String jsonStr = "{\"name\":\"zhangsan\",\"email\":\"15\"}";
        
 User user = JSON.parseObject(jsonStr,User.class);

8. 将 json 字符串转换为 JSONArray 数组

 String jsonStr = "[{\"name\":\"zhangsan\",\"email\":\"zhangsan@qq.com\"},{\"name\":\"lisi\",\"email\":\"lisi@163.com\"}]";
        
        JSONArray array = JSON.parseArray(jsonStr);

        for(int i=0;i<array.size();i++){
            System.out.println(array.get(i));
        }

9. 将Java 对象转换为 json 字符串

 User user = new User(11,"wangwu","wangwu@163.com","上海");
        
 String str = JSON.toJSONString(user);

10. 将json 字符串转换为 Java 实体集合

 String jsonStr = "[{\"name\":\"zhangsan\",\"email\":\"zhangsan@qq.com\"},{\"name\":\"lisi\",\"email\":\"lisi@163.com\"}]";

 List<User> list = JSON.parseArray(jsonStr,User.class);

11. 将 java 对象转换为 JsonObject

  User user = new User(11,"wangwu","wangwu@163.com","上海");

  JSONObject jsonObject = (JSONObject) JSON.toJSON(user);

二、org.json.JSONObject

1.添加依赖

　<dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
            <version>20180130</version>
 </dependency>

2.Bean 对象转换为 JSONObject

User user = new User(11,"wangwu","wangwu@163.com","上海");

JSONObject jsonObject = new JSONObject(user);

3.Map 集合转换为 JSONObject 对象

  Map<String,Object> map = new HashMap();
        map.put("name","zhangsan");
        map.put("age","15");

  JSONObject jsonObject = new JSONObject(map);

4.JSONObject 转换为 Map<String,Object>对象

    JSONObject jsonObject = new JSONObject();

    jsonObject.toMap();

三、GSON（参考）

1.添加依赖

  <dependency>
     <groupId>com.google.code.gson</groupId>
     <artifactId>gson</artifactId>
     <version>2.3.1</version>
  </dependency>

2.Gson 的两个基础方法

toJson();
fromJson();

3.创建方式一：

// 使用new方法
Gson gson = new Gson();

// toJson 将bean对象转换为json字符串
String jsonStr = gson.toJson(user, User.class);

// fromJson 将json字符串转为bean对象
Student user= gson.fromJson(jsonStr, User.class);

// **序列化List**
String jsonStr2 = gson.toJson(list);

// **反序列化成List时需要使用到TypeToken getType()**
List<User> retList = gson.fromJson(jsonStr2,new TypeToken<List<User>>(){}.getType());

创建方式二：

//serializeNulls()是GsonBuilder提供的一种配置，当字段值为空或null时，依然对该字段进行转换
Gson gson = new GsonBuilder().serializeNulls().create();

使用GsonBuilder创建Gson实例的步骤：

首先创建GsonBuilder,然后调用GsonBuilder提供的各种配置方法进行配置，最后调用GsonBuilder的create方法，将基于当前的配置创建一个Gson实例。

附录00：

 1 package entity;
 2 
 3 /**
 4  * Created by baizhuang on 2019/9/23 16:29.
 5  */
 6 
 7 public class User {
 8     private int id;
 9     private String name;
10     private String email;
11     private String address;
12 
13     public User() {
14     }
15 
16     public User(int id, String name, String email, String address) {
17         this.id = id;
18         this.name = name;
19         this.email = email;
20         this.address = address;
21     }
22 
23     @Override
24     public String toString() {
25         return "User{" +
26                 "id=" + id +
27                 ", name='" + name + '\'' +
28                 ", email='" + email + '\'' +
29                 ", address='" + address + '\'' +
30                 '}';
31     }
32 
33     public int getId() {
34         return id;
35     }
36 
37     public void setId(int id) {
38         this.id = id;
39     }
40 
41     public String getName() {
42         return name;
43     }
44 
45     public void setName(String name) {
46         this.name = name;
47     }
48 
49     public String getEmail() {
50         return email;
51     }
52 
53     public void setEmail(String email) {
54         this.email = email;
55     }
56 
57     public String getAddress() {
58         return address;
59     }
60 
61     public void setAddress(String address) {
62         this.address = address;
63     }
64 }
View Code

附录01：

  1 package entity;
  2 
  3 import com.alibaba.fastjson.JSON;
  4 import com.alibaba.fastjson.JSONArray;
  5 import com.alibaba.fastjson.JSONObject;
  6 import java.util.Arrays;
  7 import java.util.HashMap;
  8 import java.util.List;
  9 import java.util.Map;
 10 
 11 /**
 12  * Created by baizhuang on 2019/9/23 16:30.
 13  */
 14 
 15 public class Test {
 16 
 17     public static List<User> findAllUser(){
 18         return  Arrays.asList(
 19                 new User(1,"zhangsan","zhang","北京"),
 20                 new User(2,"lisi","li","上海"));
 21 
 22     }
 23 
 24 
 25     public static void listToJsonString(){
 26         List<User> users= findAllUser();
 27 
 28         System.out.println(users);
 29 
 30         String str = JSONObject.toJSONString(users);
 31 
 32         System.out.println(str);
 33     }
 34 
 35 
 36     public static  void maptoJsonObject(){
 37         Map<String,Object> map = new HashMap();
 38         map.put("name","zhangsan");
 39         map.put("age","15");
 40         JSONObject jsonObject = new JSONObject(map);
 41         System.out.printf("Json:"+jsonObject);
 42 
 43         String jsonStr = JSON.toJSONString(map);
 44         System.out.println(jsonStr);
 45 
 46     }
 47 
 48 
 49     public static void stringToMap(){
 50 
 51         String jsonStr = "{\"name\":\"zhangsan\",\"age\":\"15\"}";
 52 
 53         JSONObject  jsonObject = JSONObject.parseObject(jsonStr);
 54 
 55         Map<String,Object> map = jsonObject;
 56 
 57     }
 58 
 59 
 60     public static  void jsonToJsonObject(){
 61         String jsonStr = "{\"name\":\"zhangsan\",\"age\":\"15\"}";
 62 
 63         JSONObject jsonObject = JSON.parseObject(jsonStr);
 64 
 65         System.out.println(jsonObject);
 66     }
 67 
 68     public static void jsonStrToJsonBean(){
 69         String jsonStr = "{\"name\":\"zhangsan\",\"email\":\"15\"}";
 70 
 71         User user = JSON.parseObject(jsonStr,User.class);
 72 
 73         System.out.println(user);
 74     }
 75 
 76     public static void jsonStrToJsonArray(){
 77         String jsonStr = "[{\"name\":\"zhangsan\",\"email\":\"zhangsan@qq.com\"},{\"name\":\"lisi\",\"email\":\"lisi@163.com\"}]";
 78 
 79         JSONArray array = JSON.parseArray(jsonStr);
 80 
 81         for(int i=0;i<array.size();i++){
 82             System.out.println(array.get(i));
 83         }
 84     }
 85 
 86     public static void javaBeanToJsonStr(){
 87         User user = new User(11,"wangwu","wangwu@163.com","上海");
 88 
 89         String str = JSON.toJSONString(user);
 90         System.out.println(str);
 91     }
 92 
 93     public static void jsonStrToBeanList(){
 94         String jsonStr = "[{\"name\":\"zhangsan\",\"email\":\"zhangsan@qq.com\"},{\"name\":\"lisi\",\"email\":\"lisi@163.com\"}]";
 95         List<User> list = JSON.parseArray(jsonStr,User.class);
 96         for(User user : list){
 97             System.out.println(user);
 98         }
 99     }
100 
101     public static void beanToJsonObject(){
102         User user = new User(11,"wangwu","wangwu@163.com","上海");
103 
104         JSONObject jsonObject = (JSONObject) JSON.toJSON(user);
105 
106         System.out.println(jsonObject);
107 
108     }
109 
110     public static void main(String []args){
111         //listToJsonString();
112         //();
113        // stringToMap();
114        // jsonToJsonObject();
115        // jsonStrToJsonBean();
116         //jsonStrToJsonArray();
117        // javaBeanToJsonStr();
118         //jsonStrToBeanList();
119         beanToJsonObject();
120 
121     }
122 }
View Code

附录02：

 1 public class TestOrgJson {
 2 
 3     public static void beanToJSONObject(){
 4         User user = new User(11,"wangwu","wangwu@163.com","上海");
 5 
 6         JSONObject jsonObject = new JSONObject(user);
 7 
 8         System.out.println(jsonObject);
 9     }
10 
11     public static void mapToJSONObject(){
12 
13         Map<String,Object> map = new HashMap();
14         map.put("name","zhangsan");
15         map.put("age","15");
16 
17         JSONObject jsonObject = new JSONObject();
18         jsonObject.toMap();
19     }
20 
21 
22     public static void main(String []args){
23 
24 
25 
26     }
27 }
View Code

 

posted @ 2019-09-23 15:09  byebai95  阅读(3836)  评论(0)  编辑  收藏  举报