Detailed explanation of JSONObject usage

 <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.28</version>
        </dependency>

JSONObject zhangsan = new JSONObject();
        try {
            //Add zhangsan.put("name", "张三");
            zhangsan.put("age", 18.4);
            zhangsan.put("birthday", "1900-20-03");
            zhangsan.put("majar", new String[] {"哈哈","嘿嘿"});
            zhangsan.put("null", null);
            zhangsan.put("house", false);
            System.out.println(zhangsan.toString());
        } catch (JSONException e) {
            e.printStackTrace();
        }

     HashMap<String, Object> zhangsan = new HashMap<>();
        
        zhangsan.put("name", "张三");
        zhangsan.put("age", 18.4);
        zhangsan.put("birthday", "1900-20-03");
        zhangsan.put("majar", new String[] {"哈哈","嘿嘿"});
        zhangsan.put("null", null);
        zhangsan.put("house", false);
        System.out.println(new JSONObject(zhangsan).toString());

        Student student = new Student();
        student.setId(1);
        student.setAge("20");
        student.setName("张三");
        //Generate json format System.out.println(JSON.toJSON(student));
        //Convert the object to string
        String stuString = JSONObject.toJSONString(student);

String studentString = "{\"id\":1,\"age\":2,\"name\":\"zhang\"}";
 
//Convert JSON string into JSON object JSONObject jsonObject1 = JSONObject.parseObject(stuString);
 
System.out.println(jsonObject1);

ArrayList<Student> studentLsit = new ArrayList<>();
        Student student1 = new Student();
        student1.setId(1);
        student1.setAge("20");
        student1.setName("asdasdasd");
 
        studentLsit.add(student1);
 
        Student student2 = new Student();
        student2.setId(2);
        student2.setAge("20");
        student2.setName("aaaa:;aaa");
 
        studentLsit.add(student2);
 
        // list to json string String string = JSON.toJSON(studentLsit).toString();
        System.out.println(string);
 
        //Convert json string to listJson format JSONArray jsonArray = JSONObject.parseArray(string);
 
        System.out.println(jsonArray);