Java解析json数组三种情况

 1 package com.example.demo.json;
 2  
 3  
 4 import java.util.Map;
 5  
 6 import com.alibaba.fastjson.JSON;
 7 import com.alibaba.fastjson.JSONArray;
 8 import com.alibaba.fastjson.JSONObject;
 9 import com.alibaba.fastjson.TypeReference;
10 import com.example.demo.common.Person;
11  
12  
13 public class JsonLib {
14     //json字符串-简单对象型
15     private static final String  JSON_OBJ_STR = "{"studentName":"lily","studentAge":12}";
16     //json字符串-数组类型
17     private static final String  JSON_ARRAY_STR = "[{"studentName":"lily","studentAge":12},{"studentName":"lucy","studentAge":15}]";
18     //复杂格式json字符串
19     private static final String  COMPLEX_JSON_STR = "{"teacherName":"crystall","teacherAge":27,"course":{"courseName":"english","code":1270},"students":[{"studentName":"lily","studentAge":12},{"studentName":"lucy","studentAge":15}]}";
20     @SuppressWarnings("unchecked")
21    public static void main(String[] args) {
22        //demoJson();
23         
24         //testJSONStrToJSONObject();//json字符串转化对象
25         //testJSONStrToJSONArray();//json数组转化json对象
26         testComplexJSONStrToJSONObject();//json对象嵌套json对象
27    }
28     
29     /**
30      * 复杂json格式字符串与JSONObject之间的转换
31      */
32     public static void testComplexJSONStrToJSONObject(){
33         System.out.println(COMPLEX_JSON_STR);
34         JSONObject jsonObject = JSON.parseObject(COMPLEX_JSON_STR);
35         //JSONObject jsonObject1 = JSONObject.parseObject(COMPLEX_JSON_STR);//因为JSONObject继承了JSON，所以这样也是可以的
36         System.out.println(jsonObject);
37         String teacherName = jsonObject.getString("teacherName");
38         Integer teacherAge = jsonObject.getInteger("teacherAge");
39         JSONObject course = jsonObject.getJSONObject("course");
40         JSONArray students = jsonObject.getJSONArray("students");
41         System.out.println(teacherName+"------"+teacherAge+"===json对象===="+course+"----json数组----"+students);
42         JSONArray jsonArray = JSON.parseArray(students.toString());
43         System.out.println(jsonArray);
44     }
45     
46     /**
47      * json字符串-数组类型与JSONArray之间的转换
48      */
49     public static void testJSONStrToJSONArray(){
50  
51         JSONArray jsonArray = JSON.parseArray(JSON_ARRAY_STR);
52         //JSONArray jsonArray1 = JSONArray.parseArray(JSON_ARRAY_STR);//因为JSONArray继承了JSON，所以这样也是可以的
53  
54         //遍历方式1
55         int size = jsonArray.size();
56         for (int i = 0; i < size; i++){
57             JSONObject jsonObject = jsonArray.getJSONObject(i);
58             System.out.println(jsonObject.getString("studentName")+":"+jsonObject.getInteger("studentAge"));
59         }
60  
61         //遍历方式2
62         for (Object obj : jsonArray) {
63             JSONObject jsonObject = (JSONObject) obj;
64             System.out.println(jsonObject.getString("studentName")+":"+jsonObject.getInteger("studentAge"));
65         }
66     }
67     
68     /**
69      * json字符串-简单对象型与JSONObject之间的转换
70      */
71     public static void testJSONStrToJSONObject(){
72  
73         JSONObject jsonObject = JSON.parseObject(JSON_OBJ_STR);
74         //JSONObject jsonObject1 = JSONObject.parseObject(JSON_OBJ_STR); //因为JSONObject继承了JSON，所以这样也是可以的
75  
76         System.out.println(jsonObject.getString("studentName")+":"+jsonObject.getInteger("studentAge"));
77  
78     }
79     public static void demoJson() {
80         /**
81             * 将 Json 形式的字符串转换为 Map
82             */
83            String str = "{"name":"Tom","age":90}";
84            JSONObject jsonObject = JSONObject.parseObject(str);
85            Map<String, String> params = JSONObject.parseObject(jsonObject.toString(), new TypeReference<Map<String, String>>(){});
86            System.out.println(params);
87  
88            /**
89             * 将 Json 形式的字符串转换为 JavaBean
90             */
91              str = "{"id":"A001","name":"Jack"}";
92              jsonObject = JSONObject.parseObject(str);
93              System.out.println(jsonObject);
94              Person person = JSON.parseObject(str, new TypeReference<Person>() {});
95              System.out.println(person.toString());
96     }
97 }
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