对象和json字符串互转

    package com.wsh;

   import com.alibaba.fastjson.JSON;
   import com.wsh.entity.User;

   public class Test {

      public static void main(String[] args) {
          User user = new User(1,"测试",18);
          //对象转json字符串
          String json = String.valueOf(JSON.toJSON(user));
          System.out.println(json);
          //json字符串转对象
          User user1 = JSON.parseObject(json, User.class);
          System.out.println(user1);
      }
   }

输出结果

{"id":1,"userName":"测试","age":18}
User{id=1, userName='测试', age=18}

Map与json字符串互转

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Test {

    public static void main(String[] args) {
        User user = new User(1,"测试",18);
        Map<String,Object> map = new HashMap<>();
        map.put("logo","https://www.moerats.com/usr/themes/handsome/usr/img/sj/4.jpg");
        List<User> users = new ArrayList<>();
        for (int i = 0; i < 5; i++) {
            user = new User(i+1,"测试"+i+1,18+i);
            users.add(user);
        }
        map.put("userList",users);
        map.put("name","wsh");

        String mapjson = String.valueOf(JSON.toJSON(map));
        System.out.println(mapjson);
        Map<String,Object> map1=JSON.parseObject(mapjson,Map.class);
        System.out.println(map1);
    }
}

输出结果

{"name":"wsh","logo":"https://www.moerats.com/usr/themes/handsome/usr/img/sj/4.jpg","userList":[{"id":1,"userName":"测试01","age":18},{"id":2,"userName":"测试11","age":19},{"id":3,"userName":"测试21","age":20},{"id":4,"userName":"测试31","age":21},{"id":5,"userName":"测试41","age":22}]}
{userList=[{"id":1,"userName":"测试01","age":18},{"id":2,"userName":"测试11","age":19},{"id":3,"userName":"测试21","age":20},{"id":4,"userName":"测试31","age":21},{"id":5,"userName":"测试41","age":22}], name=wsh, logo=https://www.moerats.com/usr/themes/handsome/usr/img/sj/4.jpg}

Process finished with exit code 0