json对象转map，map转json

public static void main(String[] args) {
        HashMap<String,String> map = new HashMap<String, String>();
        map.put("a","1");
        map.put("b","2");
        map.put("c","3");
        System.out.println(map);
        String json = JSON.toJSONString(map);//map转String
        System.out.println(json);
        String jsonString = JSONObject.toJSONString(map);
        System.out.println(jsonString);
        JSONObject jsonObject = JSON.parseObject(json);
        System.out.println(jsonObject);
        /**
         * student对象转换成json字符串 解析成map（对象）
         * map对象转换成json字符串 解析成student(对象)
          */
        Student student=new Student();
        Date date=new Date();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd ");
        sdf.format(date);
        student.setId(1);
        student.setStudentName("李四");
        student.setScore("15");
        student.setBrithday(sdf.format(date));
        String string = JSON.toJSONString(student);
        System.out.println(string);
        Map map1 = JSON.parseObject(string, Map.class);
        System.out.println(map1);
        /**
         * map对象转json字符串 方法一：json.toJSONSting();
         */
        String mapjson = JSON.toJSONString(map1);
        System.out.println(mapjson);
        /**
         * map对象转json字符串 方法二：JSONObject.toJONString();
         */
        String jsonString1 = JSONObject.toJSONString(map1);
        System.out.println(jsonString1);
        /**
         * map对象转json字符串 方法三：对象.toString();
         */
        JSONObject jsonObject1 = new JSONObject(map1);
        String toString = jsonObject1.toString();
        System.out.println(toString);

        /**
         * json字符串解析成student对象  JSON.parseObject(jsonString,Class)
         */
        Student student1 = JSON.parseObject(mapjson, Student.class);
        System.out.println(student1);
    }