1.导入hutool工具依赖

  <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.8.16</version>
        </dependency>

2.直接复制一下代码运行

import cn.hutool.json.JSONUtil;

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) throws Exception{
        Map<String,String> map = new HashMap<>();
        map.put("host","127.0.0.1");
        map.put("port","1433");
        map.put("username","xu");
        map.put("password","123456");
        //将map转json字符串
        String jsonStr = JSONUtil.toJsonStr(map);
        System.out.println("jsonStr:"+jsonStr);
        //将json字符串转map
        Map<String,String> jsonStrTomap = JSONUtil.toBean(jsonStr, Map.class);
        System.out.println("jsonStrTomap:"+jsonStrTomap);

        Person person = new Person();
        person.setAge(18);
        person.setName("妹妹今年18岁");
        //将person对象转json字符串
        String personJSonStr = JSONUtil.toJsonStr(person);
        System.out.println("personJSonStr:"+personJSonStr);
        //将person字符串转换回person对象
        Person personFromJsonStr = JSONUtil.toBean(personJSonStr, Person.class);
        System.out.println("personFromJsonStr:"+personFromJsonStr);

        //person对象集合转json字符串
        List<Person> personList = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            Person p = new Person();
            p.setAge(18+i);
            p.setName("妹妹今年"+p.getAge()+"岁");
            personList.add(p);
        }
        //将集合对象转json字符串
        String personListJsonStr = JSONUtil.toJsonStr(personList);
        System.out.println("personListJsonStr:"+personListJsonStr);
        //再将json字符串转回到对象集合
        List<Person> personListFromJsonStr = JSONUtil.toList(personListJsonStr, Person.class);
        System.out.println("personListFromJsonStr:"+personListFromJsonStr);
    }


    static class Person {
        public String name;
        public int age;

        public Person() {}
        public Person(String name, int age) {
            this.name = name;
            this.age = age;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public int getAge() {
            return age;
        }

        public void setAge(int age) {
            this.age = age;
        }

        @Override
        public String toString() {
            return "Person{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    }

}