方法一：URL 建立连接进行接收数据

依赖

<dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.80</version>
        </dependency>

首先模拟一个接口，返回数据

controller层用的mybatic-plus

package com.zsp.chaoshi.controller;


import com.zsp.chaoshi.pojo.Jiushui;
import com.zsp.chaoshi.service.JiushuiService;
import com.zsp.chaoshi.service.SavehttpService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**
 * <p>
 *  前端控制器
 * </p>
 *
 * @author zsp
 * @since 2022-04-25
 */
@CrossOrigin
@RestController
@RequestMapping("/savehttp")
public class SavehttpController {
    @Autowired
    private JiushuiService jiushuiService;
    @Autowired
    private SavehttpService savehttpService;

/**
 模拟对外暴露的接口
 */
    @GetMapping("/doGetControllerOne")
    public List<Jiushui> doHttp(){
        List<Jiushui> list = jiushuiService.list();
        return list;
    }

/**
 获取接口并保存到数据库的方法
 */
    @GetMapping("/saveMysql")
    public String saveMysql(){
        savehttpService.saveMysql();
        return "存入成功";
    }
}

要接收controller层的doGetControllerOne传过来的数据，所以根据传过来的字段首先建立数据库，要跟传过来的数据的字段保持一致。

接收数据对应的pojo类。

package com.zsp.chaoshi.pojo;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableField;
import java.io.Serializable;

import com.baomidou.mybatisplus.extension.activerecord.Model;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.experimental.Accessors;

/**
 * <p>
 * 
 * </p>
 *
 * @author zsp
 * @since 2022-04-25
 */
@Data
@EqualsAndHashCode(callSuper = false)
@Accessors(chain = true)
public class Savehttp extends Model<Savehttp> implements Serializable {

    private static final long serialVersionUID=1L;
    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;

    private String name;

    private Integer jiage;

    private String tupian;

    private Integer isdeleted;

    @TableField("VERSION")
    private Integer version;

    private int sex;


}

service层这里不写实体类参数原因见serviceImpl

package com.zsp.chaoshi.service;

import com.zsp.chaoshi.pojo.Savehttp;
import com.baomidou.mybatisplus.extension.service.IService;

/**
 * <p>
 *  服务类
 * </p>
 *
 * @author zsp
 * @since 2022-04-25
 */
public interface SavehttpService extends IService<Savehttp> {

    void saveMysql();
}

serviceImpl类

package com.zsp.chaoshi.service.impl;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.zsp.chaoshi.pojo.Savehttp;
import com.zsp.chaoshi.mapper.SavehttpMapper;
import com.zsp.chaoshi.service.SavehttpService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Optional;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author zsp
 * @since 2022-04-25
 */
@Service

public class SavehttpServiceImpl extends ServiceImpl<SavehttpMapper, Savehttp> implements SavehttpService {

    @Autowired
    SavehttpMapper savehttpMapper;

    @Override
    public void saveMysql() {

        String path = "http://127.0.0.1:8083/savehttp/doGetControllerOne";
        BufferedReader in = null;
        StringBuffer result = null;
        try {
            URL url = new URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.connect();
            result = new StringBuffer();
            //读取url的响应
            in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
            //我接受的数据是[{}]数组类型的，所以要用数组类型的JSON去接收，如果接收的是Object{}，那么就要用JSONObject去接收
            //JSONArray array = JSONArray.parseArray(str); 接收的是数组格式的数据
            //JSONObject  obj = JSONArray.parseObject(str);接收的是对象
            //parseArray方法接收的是String字符串，所以不能直接传Stringbuffer进来，要进行valueOf转换
            //这里用valueOf是因为如果对象为空，则返回null字符串；否则用toString的话，对象为空则会报空指针异常
            JSONArray jsonArray = JSON.parseArray(String.valueOf(result));
            //此时存进来的jsonArray就是JSON数组
            //[
            // {
            //  "tupian":"100",
            //  "isDeleted":0,
            //  "jiage":120,
            //  "sex":1,
            //  "name":"外星人笔记本",
            //  "id":1,
            //  "version":2
            //  },
            //  {
            //  "tupian":"20",
            //  "isDeleted":0,
            //  "jiage":666,
            //  "sex":2,
            //  "name":"11111",
            //  "id":52,
            //  "version":0,
            //  }
            //]

            //接下来就是遍历数组下标，获取每个下标里面的数据 也就是取值
            //用法:
            // for(int i =0; i <= array.size(); i++){
            //		 	array[i].get(key);
            //	 	}
            for (int i = 0; i < jsonArray.size(); i++) {
                JSONObject jsonObject = jsonArray.getJSONObject(i); //获取
                Savehttp savehttp = new Savehttp();
                //savehttp.setId(jsonObject.getInteger("id"));
                savehttp.setName(jsonObject.getString("name"));
                savehttp.setJiage(jsonObject.getInteger("jiage"));
                savehttp.setTupian(jsonObject.getString("tupian"));
                savehttp.setIsdeleted(jsonObject.getInteger("isDeleted"));
                savehttp.setVersion(jsonObject.getInteger("version"));
                savehttp.setSex(jsonObject.getInteger("sex"));
                savehttp.insert();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

postman测试，成功。

方法二：httpClient建立连接获取数据

这个没有写接口，只在Test里面做了测试别的不变，有的import没用到。

 import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.zsp.chaoshi.mapper.JiushuiMapper;
import com.zsp.chaoshi.mapper.SavehttpMapper;
import com.zsp.chaoshi.mapper.UserMapper;
import com.zsp.chaoshi.pojo.Jiushui;
import com.zsp.chaoshi.pojo.Savehttp;
import com.zsp.chaoshi.pojo.User;
import com.zsp.chaoshi.service.JiushuiService;
import org.apache.http.HttpEntity;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;
import javax.annotation.Resource;
import java.io.IOException;
import java.util.List;
@Test
    public void doGetTestOne() {
        // 获得Http客户端(可以理解为:你得先有一个浏览器;注意:实际上HttpClient与浏览器是不一样的)
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        // 创建Get请求
        HttpGet httpGet = new HttpGet("http://127.0.0.1:8083/savehttp/doGetControllerOne");

        // 响应模型
        CloseableHttpResponse response = null;
        try {
            // 由客户端执行(发送)Get请求
            response = httpClient.execute(httpGet);
            // 从响应模型中获取响应实体
            HttpEntity responseEntity = response.getEntity();
            System.out.println("响应状态为:" + response.getStatusLine());
            if (responseEntity != null) {
                System.out.println("响应内容长度为:" + responseEntity.getContentLength());
                JSONArray jsonArray= JSON.parseArray(EntityUtils.toString(responseEntity));
                for (int i = 0; i < jsonArray.size(); i++) {
                    JSONObject jsonObject = jsonArray.getJSONObject(i);
                    Savehttp savehttp = new Savehttp();
                   savehttp.setName(jsonObject.getString("name"));
                savehttp.setJiage(jsonObject.getInteger("jiage"));
                savehttp.setTupian(jsonObject.getString("tupian"));
                savehttp.setIsdeleted(jsonObject.getInteger("isDeleted"));
                savehttp.setVersion(jsonObject.getInteger("version"));
                savehttp.setSex(jsonObject.getInteger("sex"));
                savehttp.insert();
                }
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (ParseException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                // 释放资源
                if (httpClient != null) {
                    httpClient.close();
                }
                if (response != null) {
                    response.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

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