java-json（一）

1.什么是josn？(JavaScript Object Notation)

2.两种结构:对象和数组

{"videolist":[{"id":"d7ee747f-6e70-4b09-adf7-af16931d31fe","name":"name","timestamp":"2019-11-20 21:33:51","title":"xxxxx","description":"这是一条视频","author":"詹姆斯","face":"/face/","author_id":"1010","create_at":"2019-11-20 21:33:51","auditingDte":"2019-11-20 21:33:51","coins":0,"duration":null,"subtitle":null,"typeid":null}],"videolist_count":5}

图例：

3.应用：

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

import java.util.*;

public class Jsontest {


    public static void main(String args[]) {

        List<Map<String, Object>> numList =new ArrayList<Map<String, Object>>();
        
        for (int i = 0; i <3 ; i++) {
            Map<String, Object> map=new HashMap<String, Object>();
            String key=String.valueOf((Math.random()*9+1)*1000);
            map.put(key,(int)((Math.random()*9+1)*1000));
            String json = JSONObject.toJSONString(map);
            System.out.println("json:"+json);
            numList.add(map);
        }
        
        System.out.println("numList:"+numList);
        System.out.println("===================分割线1:");


        String jsondata="{\"contend\":[{\"bid\":\"22\",\"carid\":\"0\"},{\"bid\":\"22\",\"carid\":\"0\"}],\"result\":100,\"total\":2}";
        JSONObject obj= JSON.parseObject(jsondata);

        System.out.println(obj.get("result"));
        System.out.println(obj);

        System.out.println("===================分割线2:");
        Map<String, Object> map=new HashMap<String, Object>();
        map.put("key","123");
        map.put("code","00");
        map.put("msg","成功");

        JSONObject paramsObj = new JSONObject(map);
        System.out.println(paramsObj);
        
    }
}

打印：