JSONObject obj = new JSONObject();

obj.put("sex", "male");

obj.put("age", 22);

obj.put("is_student", true);

obj.put("hobbies", new String[] {"hiking", "swimming"});

//调用toString()方法可直接将其内容打印出来

System.out.println(obj.toString());

结果：

{"hobbies":["hiking","swimming"],"sex":"male","name":"John","is_student":true,"age":22}

key值必须为String类型， value可以为boolean、double、int、long、Object、Map以及Collection等。
当然，double以及int等类型只是在Java中，写入到json中时，统一都会以Number类型存储。

Map<String, Object> data = new HashMap<String, Object>();

data.put("name", "John");

data.put("sex", "male");

data.put("age", 22);

data.put("is_student", true);

data.put("hobbies", new String[] {"hiking", "swimming"});

JSONObject obj = new JSONObject(data);

System.out.println(obj.toString());   

//JavaBean

public class PersonInfo {

    private String name;

    private String sex;

    private int age;

    private boolean isStudent;

    private String[] hobbies;

    public void setName(String name) {

        this.name = name;

    }

    public void setSex(String sex) {

        this.sex = sex;

    }

    public void setAge(int age) {

        this.age = age;

    }

    public void setStudent(boolean isStudent) {

        this.isStudent = isStudent;

    }

    public void setHobbies(String[] hobbies) {

        this.hobbies = hobbies;

    }

    //getter不能少

    public String getName() {

        return name;

    }

    public String getSex() {

        return sex;

    }

    public int getAge() {

        return age;

    }

    public boolean isStudent() {

        return isStudent;

    }

    public String[] getHobbies() {

        return hobbies;

    }

}

//Main

import org.json.JSONObject;

public class JSONObjectSample {

    public static void main(String[] args) {

        createJsonByJavaBean();

    }

    private static void createJsonByJavaBean() {

        PersonInfo info = new PersonInfo();

        info.setName("John");

        info.setSex("male");

        info.setAge(22);

        info.setStudent(true);

        info.setHobbies(new String[] {"hiking", "swimming"});

        JSONObject obj = new JSONObject(info);

        System.out.println(obj);

    }

}

@RequestMapping("/view")

public ModelAndView user(HttpServletRequest request,User user){

     String path = request.getParameter("path") + "";

     String contextPath = request.getContextPath();

     ModelAndView mav = new ModelAndView();

     JSONObject jsonObj = new JSONObject();

     jsonObj = userService.getGroupList(user);

     //判断JSON是否存在error_msg，存在则请求失败，返回错误信息

　　　if(jsonObj.has("error_msg")){

     　　String error_msg = (String) jsonObj.get("error_msg");

         mav.addObject("msg",error_msg );

     }else{//解析JSON，获取用户组列表

         //Integer result_num= jsonObj.getInt("result_num");//返回结果数

         JSONArray result = jsonObj.getJSONArray("result");

         String resStr = result.toString();

         resStr = resStr.replace("[", "").replace("]", "").replace("\"", "");

         String[] groupList = resStr.split(",");

         mav.addObject("groupList", groupList);

     }

     mav.addObject("contextPath", contextPath);

     mav.setViewName(path);

     return mav;
}