用JSONObject解析和处理json数据

àì夳堔傛蜴生んèń 2022-06-02 11:59 168阅读 0赞

文章转自：[http://www.cnblogs.com/jiayongji/p/6417862.html][http_www.cnblogs.com_jiayongji_p_6417862.html]

1、解析简单的json字符串：

// 简单的json测试字符串
    public static final String JSON_SIMPLE = "{'name':'tom','age':16}";
    
    JSONObject obj = JSONObject.fromObject(JSON_SIMPLE);
    System.out.println("name is : " + obj.get("name"));
    System.out.println("age is : " + obj.get("age"));

输出：

name is : tom
    age is : 16

2、解析嵌套的json字符串：

// 嵌套的json字符串
    public static final String JSON_MULTI = "{'name':'tom','score':{'Math':98,'English':90}}";
    
    JSONObject obj = JSONObject.fromObject(JSON_MULTI);
    System.out.println("name is : " + obj.get("name"));
    System.out.println("score is : " + obj.get("score"));
    
     JSONObject scoreObj = (JSONObject) obj.get("score");
    System.out.println("Math score is : " + scoreObj.get("Math"));
    System.out.println("English score is : " + scoreObj.get("English"));

输出：

name is : tom
    score is : {
       "English":90,"Math":98}
    Math score is : 98
    English score is : 90

3、把bean对象转化成JSONObject对象：

Person、Info、Score类分别如下：（注：要定义成独立的三个public类，不能定义成内部类或非public类，否则会转换异常）

public class Person {
       private String name;
    
       private Info info;
    
       public String getName() {
            return name;
       }
    
       public void setName(String name) {
           this.name = name;
       }
    
       public Info getInfo() {
          return info;
       }
    
       public void setInfo(Info info) {
          this.info = info;
       }
    
       @Override
       public String toString() {
          return "Person [name=" + name + ", info=" + info + "]";
       }
    
     }

public class Info {
       private int age;
       private Score score;
    
       public int getAge() {
          return age;
       }
    
       public void setAge(int age) {
          this.age = age;
       }
    
       public Score getScore() {
          return score;
       }
    
       public void setScore(Score score) {
          this.score = score;
       }
    
       @Override
       public String toString() {
          return "Info [age=" + age + ", score=" + score + "]";
       }
    
     }

public class Score {
       private String math;
       private String english;
    
       public String getMath() {
          return math;
       }
    
       public void setMath(String math) {
          this.math = math;
       }
       public String getEnglish() {
          return english;
       }
    
       public void setEnglish(String english) {
          this.english = english;
       }
    
       @Override
       public String toString() {
          return "Score [math=" + math + ", english=" + english + "]";
       }
    
    }

转换方法：

Score score = new Score();
    score.setEnglish("A");
    score.setMath("B");
    
    Info info = new Info();
    info.setAge(20);
    info.setScore(score);
    
    Person person = new Person();
    person.setInfo(info);
    person.setName("Tim");
    
    JSONObject obj = JSONObject.fromObject(person);
    System.out.println(obj.toString());

输出：

{
        "name": "Tim",
        "info": { "score": { "english": "A", "math": "B" }, "age": 20 } }

4、把json数组转换成JsonObject数组：

// 数组形式的json
    public static final String JSON_ARRAY = "[{'name':'tom'},{'name':'john','age':20},{}]";
    
    JSONArray arr = JSONArray.fromObject(JSON_ARRAY);
    System.out.println(arr);
    
    for (int i = 0; i < arr.size(); i++) {
        JSONObject obj = arr.getJSONObject(i);
        System.out.println(obj.toString());
     }

输出：

[{"name":"tom"},{"name":"john","age":20},{}]
    {"name":"tom"}
    {"name":"john","age":20}
    {}

5、构造一个json字符串：

JSONObject obj = new JSONObject();
    obj.put("name", "tom");
    obj.put("age", 19);
    
    // 子对象
    JSONObject objContact = new JSONObject();
    objContact.put("tel", "123456");
    objContact.put("email", "tom@test.com");
    obj.put("contact", objContact);
    
    // 子数组对象
    JSONArray scoreArr = new JSONArray();
    JSONObject objEnglish = new JSONObject();
    objEnglish.put("course", "english");
    objEnglish.put("result", 100);
    objEnglish.put("level", "A");
    
    JSONObject objMath = new JSONObject();
    objMath.put("course", "math");
    objMath.put("result", 50);
    objMath.put("level", "D");
    
    scoreArr.add(objEnglish);
    scoreArr.add(objMath);
    
    obj.put("score", scoreArr);
    
    System.out.println(obj.toString());

输出：

{
        "score": [ { "result": 100, "level": "A", "course": "english" }, { "result": 50, "level": "D", "course": "math" } ],
        "contact": { "tel": "123456", "email": "tom@test.com" },
        "name": "tom",
        "age": 19 }

[http_www.cnblogs.com_jiayongji_p_6417862.html]: http://www.cnblogs.com/jiayongji/p/6417862.html