Java调用第三方http接口的方式

刺骨的言语ヽ痛彻心扉 2021-12-10 13:29 316阅读 0赞

转载：[https://www.cnblogs.com/swordfall/p/10757499.html][https_www.cnblogs.com_swordfall_p_10757499.html]

# 1. 概述 #

在实际开发过程中，我们经常需要调用对方提供的接口或测试自己写的接口是否合适。很多项目都会封装规定好本身项目的接口规范，所以大多数需要去调用对方提供的接口或第三方接口（短信、天气等）。

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；

②通过common封装好的HttpClient；

③通过Apache封装好的CloseableHttpClient；

④通过SpringBoot-RestTemplate；

# 2. Java调用第三方http接口的方式 #

## 2.1 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，直接上代码：

import java.io.*;
    import java.net.HttpURLConnection;
    import java.net.MalformedURLException;
    import java.net.URL;
    
    /**
     * @Author: Yang JianQiu
     * @Date: 2019/4/26 11:34
     * jdk类HttpURLConnection调用第三方http接口
     *
     * 通常分get和post两种方式
     *
     * 参考资料：
     * http://www.cnblogs.com/angusbao/p/7727649.html
     */
    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", "");
        }
    }

## 2.2 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。

导入如下jar包：

<dependency>
                <groupId>commons-httpclient</groupId>
                <artifactId>commons-httpclient</artifactId>
                <version>3.1</version>
            </dependency>

代码如下：

import com.alibaba.fastjson.JSONObject;
    import org.apache.commons.httpclient.*;
    import org.apache.commons.httpclient.methods.GetMethod;
    import org.apache.commons.httpclient.methods.PostMethod;
    import org.apache.commons.httpclient.params.HttpMethodParams;
    
    import java.io.IOException;
    import java.io.InputStream;
    
    /**
     * @Author: Yang JianQiu
     * @Date: 2019/4/28 11:07
     *
     * HttpClient模拟get、post请求并发送请求参数（json等）
     * 【参考资料】
     * https://javasam.iteye.com/blog/2117845
     * https://blog.csdn.net/qq_28379809/article/details/82898792
     */
    public class HttpClientToInterface {
    
        /**
         * httpClient的get请求方式
         * 使用GetMethod来访问一个URL对应的网页实现步骤：
         * 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。
         * @param url
         * @param charset
         * @return
         */
        public static String doGet(String url, String charset){
            /**
             * 1.生成HttpClient对象并设置参数
             */
            HttpClient httpClient = new HttpClient();
            //设置Http连接超时为5秒
            httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(5000);
    
            /**
             * 2.生成GetMethod对象并设置参数
             */
            GetMethod getMethod = new GetMethod(url);
            //设置get请求超时为5秒
            getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 5000);
            //设置请求重试处理，用的是默认的重试处理：请求三次
            getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler());
    
            String response = "";
    
            /**
             * 3.执行HTTP GET 请求
             */
            try {
                int statusCode = httpClient.executeMethod(getMethod);
    
                /**
                 * 4.判断访问的状态码
                 */
                if (statusCode != HttpStatus.SC_OK){
                    System.err.println("请求出错：" + getMethod.getStatusLine());
                }
    
                /**
                 * 5.处理HTTP响应内容
                 */
                //HTTP响应头部信息，这里简单打印
                Header[] headers = getMethod.getResponseHeaders();
                for (Header h: headers){
                    System.out.println(h.getName() + "---------------" + h.getValue());
                }
                //读取HTTP响应内容，这里简单打印网页内容
                //读取为字节数组
                byte[] responseBody = getMethod.getResponseBody();
                response = new String(responseBody, charset);
                System.out.println("-----------response:" + response);
                //读取为InputStream，在网页内容数据量大时候推荐使用
                //InputStream response = getMethod.getResponseBodyAsStream();
    
            } catch (HttpException e) {
                //发生致命的异常，可能是协议不对或者返回的内容有问题
                System.out.println("请检查输入的URL!");
                e.printStackTrace();
            } catch (IOException e){
                //发生网络异常
                System.out.println("发生网络异常!");
            }finally {
                /**
                 * 6.释放连接
                 */
                getMethod.releaseConnection();
            }
            return response;
        }
    
        /**
         * post请求
         * @param url
         * @param json
         * @return
         */
        public static String doPost(String url, JSONObject json){
            HttpClient httpClient = new HttpClient();
            PostMethod postMethod = new PostMethod(url);
    
            postMethod.addRequestHeader("accept", "*/*");
            postMethod.addRequestHeader("connection", "Keep-Alive");
            //设置json格式传送
            postMethod.addRequestHeader("Content-Type", "application/json;charset=utf-8");
            //必须设置下面这个Header
            postMethod.addRequestHeader("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");
            //添加请求参数
            postMethod.addParameter("commentId", json.getString("commentId"));
    
            String res = "";
            try {
                int code = httpClient.executeMethod(postMethod);
                if (code == 200){
                    res = postMethod.getResponseBodyAsString();
                    System.out.println(res);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            return res;
        }
    
        public static void main(String[] args) {
            doGet("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", "UTF-8");
            System.out.println("-----------分割线------------");
            System.out.println("-----------分割线------------");
            System.out.println("-----------分割线------------");
    
            JSONObject jsonObject = new JSONObject();
            jsonObject.put("commentId", "13026194071");
            doPost("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", jsonObject);
        }
    }

.3 通过Apache封装好的CloseableHttpClient

CloseableHttpClient是在HttpClient的基础上修改更新而来的，这里还涉及到请求头token的设置（请求验证），利用fastjson转换请求或返回结果字符串为json格式，当然上面两种方式也是可以设置请求头token、json的，这里只在下面说明。

导入如下jar包：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

<dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.2</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.28</version>
            </dependency>

代码如下：

import com.alibaba.fastjson.JSONObject;
    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.HttpClientBuilder;
    import org.apache.http.util.EntityUtils;
    
    import java.io.IOException;
    
    /**
     * @Author: Yang JianQiu
     * @Date: 2019/4/26 11:41
     * Apache封装好的CloseableHttpClient
     * 【参考资料】
     *  https://www.cnblogs.com/siv8/p/6222709.html
     *  https://blog.csdn.net/qq_35860138/article/details/82967727
     */
    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, JSONObject json){
            
            try {
                if (httpClient == null){
                    httpClient = HttpClientBuilder.create().build();
                }
    
                HttpPost post = new HttpPost(url);
                
                if (tokenString != null && !tokenString.equals("")){
                    tokenString = getToken();
                }
                
                //api_gateway_auth_token自定义header头，用于token验证使用
                post.addHeader("api_gateway_auth_token", tokenString);
                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(json.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);
    
                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
         */
        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");
                
                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);
                if (result.containsKey("token")){
                    token = result.getString("token");
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            return token;
        }
    
        /**
         * 测试
         */
        public static void test(String telephone){
    
            JSONObject object = new JSONObject();
            object.put("telephone", telephone);
    
            try {
                //首先获取token
                tokenString = getToken();
                String response = doPost("http://localhost/searchUrl", object);
    
                //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);
    
                System.out.println(response);
    
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        public static void main(String[] args) {
            test("12345678910");
        }
    
    }

## 2.4 通过SpringBoot-RestTemplate ##

springBoot-RestTemple是上面三种方式的集大成者，代码编写更加简单，目前可以采用的调用第三方接口有：

*  delete() 在特定的URL上对资源执行HTTP DELETE操作
 *  exchange() 在URL上执行特定的HTTP方法，返回包含对象的ResponseEntity，这个对象是从响应体中映射得到的
 *  execute() 在URL上执行特定的HTTP方法，返回一个从响应体映射得到的对象
 *  getForEntity() 发送一个HTTP GET请求，返回的ResponseEntity包含了响应体所映射成的对象
 *  getForObject() 发送一个HTTP GET请求，返回的请求体将映射为一个对象
 *  postForEntity() POST 数据到一个URL，返回包含一个对象的ResponseEntity，这个对象是从响应体中映射得到的
 *  postForObject() POST 数据到一个URL，返回根据响应体匹配形成的对象
 *  headForHeaders() 发送HTTP HEAD请求，返回包含特定资源URL的HTTP头
 *  optionsForAllow() 发送HTTP OPTIONS请求，返回对特定URL的Allow头信息
 *  postForLocation() POST 数据到一个URL，返回新创建资源的URL
 *  put() PUT 资源到特定的URL

注意：目前标红的为常用的

首先导入springboot的web包

<parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.0.4.RELEASE</version>
        </parent>
    
        <dependencies>
            
            <dependency>
                <groupId>org.apache.httpcomponents</groupId>
                <artifactId>httpclient</artifactId>
                <version>4.5.2</version>
            </dependency>
    
            
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-configuration-processor</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-aop</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>org.springframework.boot</groupId>
                        <artifactId>spring-boot-starter-tomcat</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jetty</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>

在启动类同包下创建RestTemplateConfig.java类

import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.http.client.ClientHttpRequestFactory;
    import org.springframework.http.client.SimpleClientHttpRequestFactory;
    import org.springframework.web.client.RestTemplate;
    
    /**
     * @Author: Yang JianQiu
     * @Date: 2019/4/28 14:01
     */
    @Configuration
    public class RestTemplateConfig {
    
        @Bean
        public RestTemplate restTemplate(ClientHttpRequestFactory factory){
            return new RestTemplate(factory);
        }
    
        @Bean
        public ClientHttpRequestFactory simpleClientHttpRequestFactory(){
            SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
            factory.setConnectTimeout(15000);
            factory.setReadTimeout(5000);
            return factory;
        }
    }

然后在Service类（RestTemplateToInterface ）中注入使用

具体代码如下：

import com.alibaba.fastjson.JSONObject;
    import com.swordfall.model.User;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.http.*;
    import org.springframework.stereotype.Service;
    import org.springframework.web.client.RestTemplate;
    
    /**
     * @Author: Yang JianQiu
     * @Date: 2019/4/28 14:13
     *
     * 【参考资料】
     * https://blog.csdn.net/qq_15452971/article/details/79416469
     * https://blog.csdn.net/weixin_40461281/article/details/83540604
     */
    @Service
    public class RestTemplateToInterface {
    
        @Autowired
        private RestTemplate restTemplate;
    
        /**
         * 以get方式请求第三方http接口 getForEntity
         * @param url
         * @return
         */
        public User doGetWith1(String url){
            ResponseEntity<User> responseEntity = restTemplate.getForEntity(url, User.class);
            User user = responseEntity.getBody();
            return user;
        }
    
        /**
         * 以get方式请求第三方http接口 getForObject
         * 返回值返回的是响应体，省去了我们再去getBody()
         * @param url
         * @return
         */
        public User doGetWith2(String url){
            User user  = restTemplate.getForObject(url, User.class);
            return user;
        }
    
        /**
         * 以post方式请求第三方http接口 postForEntity
         * @param url
         * @return
         */
        public String doPostWith1(String url){
            User user = new User("小白", 20);
            ResponseEntity<String> responseEntity = restTemplate.postForEntity(url, user, String.class);
            String body = responseEntity.getBody();
            return body;
        }
    
        /**
         * 以post方式请求第三方http接口 postForEntity
         * @param url
         * @return
         */
        public String doPostWith2(String url){
            User user = new User("小白", 20);
            String body = restTemplate.postForObject(url, user, String.class);
            return body;
        }
    
        /**
         * exchange
         * @return
         */
        public String doExchange(String url, Integer age, String name){
            //header参数
            HttpHeaders headers = new HttpHeaders();
            String token = "asdfaf2322";
            headers.add("authorization", token);
            headers.setContentType(MediaType.APPLICATION_JSON);
    
            //放入body中的json参数
            JSONObject obj = new JSONObject();
            obj.put("age", age);
            obj.put("name", name);
    
            //组装
            HttpEntity<JSONObject> request = new HttpEntity<>(obj, headers);
            ResponseEntity<String> responseEntity = restTemplate.exchange(url, HttpMethod.POST, request, String.class);
            String body = responseEntity.getBody();
            return body;
        }
    }

# 总结 #

【github地址】

https://github.com/SwordfallYeung/JavaInvokingHttpInterface.git

【参考资料】

[http://www.cnblogs.com/angusbao/p/7727649.html][http_www.cnblogs.com_angusbao_p_7727649.html] 纯Java api HttpURLConnection

[https://blog.csdn.net/chijiandi/article/details/81388240][https_blog.csdn.net_chijiandi_article_details_81388240] 纯Java api HttpURLConnection

[https://www.cnblogs.com/xuegu/p/8490815.html][https_www.cnblogs.com_xuegu_p_8490815.html] 封装api HttpClient

[https://www.cnblogs.com/unknows/p/8534713.html][https_www.cnblogs.com_unknows_p_8534713.html]

[https://blog.csdn.net/qq\_35860138/article/details/82967727][https_blog.csdn.net_qq_35860138_article_details_82967727] 封装api HttpClient

[https://blog.csdn.net/a1032818891/article/details/81172478][https_blog.csdn.net_a1032818891_article_details_81172478] SpringBoot-RestTemplate

[https_www.cnblogs.com_swordfall_p_10757499.html]: https://www.cnblogs.com/swordfall/p/10757499.html
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