JAVA 调用第三方接口

https://blog.csdn.net/qq_42873554/article/details/100182149?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522162630638516780264085291%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fblog.%2522%257D&request_id=162630638516780264085291&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~blog~first_rank_v2~rank_v29-2-100182149.pc_v2_rank_blog_default&utm_term=%E8%B0%83%E7%94%A8%E7%AC%AC%E4%B8%89%E6%96%B9http%E6%8E%A5%E5%8F%A3%E9%80%9A%E7%94%A8%E6%96%B9%E6%B3%95&spm=1018.2226.3001.4450

几种方式总结：
在Java项目中调用第三方接口的方式有：

①通过JDK网络类Java.net.HttpURLConnection；【Java 自带的 HttpUrlConnection 】

②使用用HttpClient调用API【经典的网络访问框架 HttpClient 】

③通过Apache封装好的CloseableHttpClient；

④通过SpringBoot-RestTemplate；【 Spring3.0 开始支持的一个 HTTP 请求工具】

1. 通过JDK网络类Java.net.HttpURLConnection

比较原始的一种调用做法，这里把get请求和post请求都统一放在一个方法里面

public class HttpUrlConnectionToInterface {

    /**
     * 以post或get方式调用对方接口方法，
     * @param pathUrl
     */
    public static void doPostOrGet(String pathUrl, String data){
        OutputStreamWriter out = null;
        BufferedReader br = null;
        String result = "";
        try {
            URL url = new URL(pathUrl);
            //打开和url之间的连接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            //请求方式
            conn.setRequestMethod("POST");
            //conn.setRequestMethod("GET");

            //设置通用的请求属性
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            conn.setRequestProperty("Content-Type", "application/json;charset=utf-8");

            //DoOutput设置是否向httpUrlConnection输出，DoInput设置是否从httpUrlConnection读入，此外发送post请求必须设置这两个
            conn.setDoOutput(true);
            conn.setDoInput(true);

            /**
             * 下面的三句代码，就是调用第三方http接口
             */
            //获取URLConnection对象对应的输出流
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            //发送请求参数即数据
            out.write(data);
            //flush输出流的缓冲
            out.flush();

            /**
             * 下面的代码相当于，获取调用第三方http接口后返回的结果
             */
            //获取URLConnection对象对应的输入流
            InputStream is = conn.getInputStream();
            //构造一个字符流缓存
            br = new BufferedReader(new InputStreamReader(is));
            String str = "";
            while ((str = br.readLine()) != null){
                result += str;
            }
            System.out.println(result);
            //关闭流
            is.close();
            //断开连接，disconnect是在底层tcp socket链接空闲时才切断，如果正在被其他线程使用就不切断。
            conn.disconnect();

        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                if (out != null){
                    out.close();
                }
                if (br != null){
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        /**
         *手机信息查询接口：http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=手机号
　　　　 *　　　　　　http://api.showji.com/Locating/www.showji.com.aspx?m=手机号&output=json&callback=querycallback
         */
        doPostOrGet("https://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", "");
    }
}

2. 通过apache common封装好的HttpClient

httpClient的get或post请求方式步骤：

1. 生成一个HttpClient对象并设置相应的参数
2. 生成一个GetMethod对象或PostMethod并设置响应的参数
3. 用HttpClient生成的对象来执行GetMethod生成的Get方法
4. 处理响应状态码
5. 若响应正常，处理HTTP响应内容
6. 释放连接

 

3、通过Apache封装好的CloseableHttpClient

package com.example.jpademo.Controller;


import com.alibaba.fastjson.JSONObject;
import com.example.jpademo.Entity.User;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

@RestController
public class CloseableHttpClientToInterface {

    private static String tokenString = "";
    private static String AUTH_TOKEN_EXPIRED = "AUTH_TOKEN_EXPIRED";
    private static CloseableHttpClient httpClient = null;

    /**
     * 以get方式调用第三方接口
     * @param url
     * @return
     */
    public static String doGet(String url, String token){
        //创建HttpClient对象
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        HttpGet get = new HttpGet(url);

        try {
            if (tokenString != null && !tokenString.equals("")){
                tokenString = getToken();
            }
            //api_gateway_auth_token自定义header头，用于token验证使用
            get.addHeader("api_gateway_auth_token", tokenString);
            get.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
            HttpResponse response = httpClient.execute(get);
            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
                //返回json格式
                String res = EntityUtils.toString(response.getEntity());
                return res;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 以post方式调用第三方接口
     * @param url
     * @param json
     * @return
     */
    public static String doPost(String url, List<JSONObject> jsonObjectList){

        try {
            HttpPost post = new HttpPost(url);

            if (httpClient == null){
                httpClient = HttpClientBuilder.create().build();
            }
            if (tokenString != null && !tokenString.equals("")){
                tokenString = getToken();
            }

            //api_gateway_auth_token自定义header头，用于token验证使用
            post.setHeader("api_gateway_auth_token", tokenString);
            post.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");

            StringEntity s = new StringEntity(jsonObjectList.toString(),"UTF-8");  // 正确
            //StringEntity s = new StringEntity(jsonObjectList.toString());
            //s.setContentEncoding("UTF-8");   //这种设置没有效果，如果jsonObjectList中有中文则API收到?号


            //设置请求参数
            post.setEntity(s);
            HttpResponse response = httpClient.execute(post);

            if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
                //返回json格式
                String res = EntityUtils.toString(response.getEntity());
                return res;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if (httpClient != null){
                try {
                    httpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

    /**
     * 获取第三方接口的token
     * Token是服务端生成的一串字符串，以作客户端进行请求的一个令牌，当第一次登录后，
     * 服务器生成一个Token便将此Token返回给客户端，以后客户端只需带上这个Token前
     * 来请求数据即可，无需再次带上用户名和密码。
     */
    public static String getToken(){

        String token = "";

        JSONObject object = new JSONObject();
        object.put("appid", "appid");
        object.put("secretkey", "secretkey");

        try {
            if (httpClient == null){
                httpClient = HttpClientBuilder.create().build();
            }
            HttpPost post = new HttpPost("http://localhost/login");

            //User-Agent:告诉服务器，客户端使用的操作系统、浏览器版本和名称
            post.addHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
            StringEntity s = new StringEntity(object.toString());
            s.setContentEncoding("UTF-8");
            //发送json数据需要设置contentType
            s.setContentType("application/x-www-form-urlencoded");
            //设置请求参数
            post.setEntity(s);
            HttpResponse response = httpClient.execute(post);

            //这里可以把返回的结果按照自定义的返回数据结果，把string转换成自定义类
            //ResultTokenBO result = JSONObject.parseObject(response, ResultTokenBO.class);

            //把response转为jsonObject
            JSONObject result = JSONObject.parseObject(response.toString());
            if (result.containsKey("token")){
                token = result.getString("token");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return token;
    }

    /**
     * 测试
     */
    @GetMapping("/HttpClient/test")
    public String test(){

        List<JSONObject> jsonObjectList=new ArrayList<JSONObject>();
        JSONObject object = new JSONObject();
        object.put("firstName", "李");
        object.put("lastName", "光明");
        object.put("email", "email李");
        jsonObjectList.add(object);

        object = new JSONObject();
        object.put("firstName", "李");
        object.put("lastName", "成功");
        object.put("email", "email李成功");
        jsonObjectList.add(object);

        try {
            //首先获取token
            tokenString = getToken();
            String response = doPost("http://localhost:8888/demo/addUsers_JSON2", jsonObjectList);

            //如果返回的结果是list形式的，需要使用JSONObject.parseArray转换
            //List<Result> list = JSONObject.parseArray(response, Result.class);
            return  response;
        } catch (Exception e) {
            e.printStackTrace();
            return "执行错误！";
        }
    }
}

4、通过SpringBoot-RestTemplate