httpclient的get带参不带参post带参不带参的简单应用

一，基础的的应用

1.1，get的无参请求

     @Test
     public void doGet() throws Exception {
         //创建一个httpclient对象
         CloseableHttpClient httpClient = HttpClients.createDefault();
         //创建一个GET对象
         HttpGet get = new HttpGet("http://www.sogou.com");
         //执行请求
         CloseableHttpResponse response = httpClient.execute(get);
         //取响应的结果
         int statusCode = response.getStatusLine().getStatusCode();
         System.out.println(statusCode);
         HttpEntity entity = response.getEntity();
         String string = EntityUtils.toString(entity, "utf-8");
         System.out.println(string);
         //关闭httpclient
         response.close();
         httpClient.close();
     }

1.2，get的带参请求

 public void doGetWithParam() throws Exception{
         //创建一个httpclient对象
         CloseableHttpClient httpClient = HttpClients.createDefault();
         //创建一个uri对象
         URIBuilder uriBuilder = new URIBuilder("http://www.sogou.com/web");
         uriBuilder.addParameter("query", "花千骨");
         HttpGet get = new HttpGet(uriBuilder.build());
         //执行请求
         CloseableHttpResponse response = httpClient.execute(get);
         //取响应的结果
         int statusCode = response.getStatusLine().getStatusCode();
         System.out.println(statusCode);
         HttpEntity entity = response.getEntity();
         String string = EntityUtils.toString(entity, "utf-8");
         System.out.println(string);
         //关闭httpclient
         response.close();
         httpClient.close();
     }

1.3，post的无参请求

 public void doPost() throws Exception {
         CloseableHttpClient httpClient = HttpClients.createDefault();

         //创建一个post对象
         HttpPost post = new HttpPost("http://localhost:8082/httpclient/post.action");
         //执行post请求
         CloseableHttpResponse response = httpClient.execute(post);
         String string = EntityUtils.toString(response.getEntity());
         System.out.println(string);
         response.close();
         httpClient.close();

     }

1.4.1，post的带参请求

 public void doPostWithParam() throws Exception{
         CloseableHttpClient httpClient = HttpClients.createDefault();

         //创建一个post对象
         HttpPost post = new HttpPost("http://localhost:8082/httpclient/post.action");
         //创建一个Entity。模拟一个表单
         List<NameValuePair> kvList = new ArrayList<>();
         kvList.add(new BasicNameValuePair("username", "张三"));
         kvList.add(new BasicNameValuePair("password", "123"));

         //包装成一个Entity对象
         StringEntity entity = new UrlEncodedFormEntity(kvList, "utf-8");
         //设置请求的内容
         post.setEntity(entity);

         //执行post请求
         CloseableHttpResponse response = httpClient.execute(post);
         String string = EntityUtils.toString(response.getEntity());
         System.out.println(string);
         response.close();
         httpClient.close();
     }

1.4.2,post的请求服务器8082的写法

 @RequestMapping(value="/httpclient/post", method=RequestMethod.POST,
             produces=MediaType.TEXT_PLAIN_VALUE+";charset=utf-8")
     @ResponseBody
     public String testPost(String username, String password) {
         String result = "username:" + username + "\tpassword:" + password;
         System.out.println(result);
         return "username:" + username + ",password:" + password;
     }

二，httpclient的工具封装

2.1，get的带参和无参的工具类

     public static String doGet(String url, Map<String, String> param) {

         // 创建Httpclient对象
         CloseableHttpClient httpclient = HttpClients.createDefault();

         String resultString = "";
         CloseableHttpResponse response = null;
         try {
             // 创建uri
             URIBuilder builder = new URIBuilder(url);
             if (param != null) {
                 for (String key : param.keySet()) {
                     builder.addParameter(key, param.get(key));
                 }
             }
             URI uri = builder.build();

             // 创建http GET请求
             HttpGet httpGet = new HttpGet(uri);

             // 执行请求
             response = httpclient.execute(httpGet);
             // 判断返回状态是否为200
             if (response.getStatusLine().getStatusCode() == 200) {
                 resultString = EntityUtils.toString(response.getEntity(), "UTF-8");
             }
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             try {
                 if (response != null) {
                     response.close();
                 }
                 httpclient.close();
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         return resultString;
     }

     public static String doGet(String url) {
         return doGet(url, null);
     }

2.2，post的带参和无参的工具类 （参数的数据类型是map）

 public static String doPost(String url, Map<String, String> param) {
         // 创建Httpclient对象
         CloseableHttpClient httpClient = HttpClients.createDefault();
         CloseableHttpResponse response = null;
         String resultString = "";
         try {
             // 创建Http Post请求
             HttpPost httpPost = new HttpPost(url);
             // 创建参数列表
             if (param != null) {
                 List<NameValuePair> paramList = new ArrayList<>();
                 for (String key : param.keySet()) {
                     paramList.add(new BasicNameValuePair(key, param.get(key)));
                 }
                 // 模拟表单
                 UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList);
                 httpPost.setEntity(entity);
             }
             // 执行http请求
             response = httpClient.execute(httpPost);
             resultString = EntityUtils.toString(response.getEntity(), "utf-8");
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             try {
                 response.close();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }

         return resultString;
     }

     public static String doPost(String url) {
         return doPost(url, null);
     }
     

2.3，post的带参的请求（参数类型是json格式的数据）

 public static String doPostJson(String url, String json) {
         // 创建Httpclient对象
         CloseableHttpClient httpClient = HttpClients.createDefault();
         CloseableHttpResponse response = null;
         String resultString = "";
         try {
             // 创建Http Post请求
             HttpPost httpPost = new HttpPost(url);
             // 创建请求内容
             StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
             httpPost.setEntity(entity);
             // 执行http请求
             response = httpClient.execute(httpPost);
             resultString = EntityUtils.toString(response.getEntity(), "utf-8");
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             try {
                 response.close();
             } catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }

         return resultString;
     }

三，项目中的案例解析 （调用其它公司的图像识别为例）

3.1，调用的服务层的方法（第一个参数不一样，说明识别的证件不一样）

     private OcrServer ocrServer = null;

     @Override
     public Map<String, Object> idCardRecognize(MultipartFile imageFile) {
         return ocrServer.pictureRecognition("IdCard", imageFile);
     }

     @Override
     public Map<String, Object> bankCardRecognize(MultipartFile imageFile) {
         return ocrServer.pictureRecognition("BankCard", imageFile);
     }

     @Override
     public Map<String, Object> veCardRecognize(MultipartFile imageFile) {
         return ocrServer.pictureRecognition("VeCard", imageFile);
     }

     @Override
     public Map<String, Object> driverCardRecognize(MultipartFile imageFile) {
         return ocrServer.pictureRecognition("DriverCard", imageFile);
     }

     @Override
     public Map<String, Object> businessLicenseRecognize(MultipartFile imageFile) {
         return ocrServer.pictureRecognition("BusinessLicense", imageFile);
     }

     @Override
     public Map<String, Object> ocrRecognize(String recotype,
             MultipartFile imageFile) {
         return ocrServer.pictureRecognition(recotype, imageFile);
     }

     public void setOcrServer(OcrServer ocrServer) {
         this.ocrServer = ocrServer;
     }

3.2，参数的封装，url的确定

 public Map<String, Object> pictureRecognition(String recotype, MultipartFile imageFile) {
         long begin = System.currentTimeMillis();
         String result = null;
         // 文件输入流
         FileInputStream fs = null;
         try {
             String configValue = cpConfigService.getValueByConfigKey("ocr_server_config", "{'uri':'http://cloud.exocr.com/recognize','username':'test','password':'test'}");
             Map<String, String> configMap = JsonUtils.json2Map2(configValue);
             String postUrl = configMap.get("uri"); // 服务地址
             Map<String, String> postParam = new HashMap<String, String>(10);
             postParam.put("username", configMap.get("username")); // 用户名， 公有云测试可使用’test’
             postParam.put("password", configMap.get("password")); // 密码，公有云测试可使用 ’test’
             postParam.put("recotype", recotype); // BankCard
             postParam.put("encoding", "utf-8"); // 返回结果的文字编码方式，取值包括：utf-8， 默认值 gb2312
             postParam.put("head_portrait", "0"); // 是否返回头像（base64格式），只对身份证识别有效，取值范围：0，默认，不返回头像    1，则返回身份证的头像照片
             postParam.put("crop_image", "0"); // 是否返回切边（base64格式），取值：0，    默认，不返回切边图    1，    返回切边图
             postParam.put("b64", "1"); // 输入图片是否为base64格式，取值：0，    默认，二进制格式   1，    base64格式
             // base64编码图像
             String base64 = new String(Base64.encodeBase64(imageFile.getBytes()));
             postParam.put("image", base64); // 待识别的图像，可以是二进制也可以是base64格式
             result = HttpUtil.postUrlAsString(postUrl, postParam, null, "utf-8");
             logger.info("OCR识别结果{}", result);
         } catch (Exception e) {
             logger.error("OCR识别异常：", e);
             StringBuilder sb = new StringBuilder();
             sb.append("{'Error':'99','Details':'OCR识别异常:");
             sb.append(e.getMessage()).append("'}");
             result = sb.toString();
         } finally {
             if (null != fs) {
                 try {
                     fs.close();
                 } catch (IOException e) {
                     logger.error("File input stream close exception:", e);
                 }
             }
         }
         // 记录接口调用耗时
         logger.info("OCR服务调用耗时{},识别类型{}", System.currentTimeMillis() - begin, recotype);

         try {
             return JsonUtils.json2Map(result);
         } catch (Exception e) {
             logger.error("json to map exception:", e);
         }

         return null;
     }

 在这里假如没有特殊的请求的话完全可以 result = HttpUtil.postUrlAsString(postUrl, postParam, null, "utf-8")调用工具类的方法了返回的结果就是了。

     public static String postUrlAsString(String url,
             Map<String, String> params, Map<String, String> reqHeader,
             String encode) throws Exception {
         // 开始时间
         long t1 = System.currentTimeMillis();
         // 获得HttpPost对象
         HttpPost httpPost = getHttpPost(url, params, encode);
         // 发送请求
         String result = executeHttpRequest(httpPost, reqHeader, encode);
         // 结束时间
         long t2 = System.currentTimeMillis();
         // 调试信息
         logger.debug("url:" + url);
         logger.debug("params:" + params.toString());
         logger.debug("reqHeader:" + reqHeader);
         logger.debug("encode:" + encode);
         logger.debug("result:" + result);
         logger.debug("consume time:" + ((t2 - t1)));
         // 返回结果
         return result;
     } 

3.3，httppost对象的获取

   private static HttpPost getHttpPost(String url, Map<String, String> params,
             String encode) throws UnsupportedEncodingException {
         HttpPost httpPost = new HttpPost(url);
         if (params != null) {
             List<NameValuePair> form = new ArrayList<NameValuePair>();
             for (String name : params.keySet()) {
                 form.add(new BasicNameValuePair(name, params.get(name)));
             }

             UrlEncodedFormEntity entity = new UrlEncodedFormEntity(form,
                     encode);
             httpPost.setEntity(entity);
         }

         return httpPost;
     }  

3.4，把获取到的参数传递给httppost对象

 private static String executeHttpRequest(HttpUriRequest request,
             Map<String, String> reqHeader, String encode) throws Exception {
         HttpClient client = null;
         String result = null;
         try {
             // 创建HttpClient对象
             client = new DefaultHttpClient();
             // 设置连接超时时间
             client.getParams().setParameter(
                     CoreConnectionPNames.CONNECTION_TIMEOUT, 60);
             // 设置Socket超时时间
             client.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT,
                     36600);
             // 设置请求头信息
             if (reqHeader != null) {
                 for (String name : reqHeader.keySet()) {
                     request.addHeader(name, reqHeader.get(name));
                 }
             }
             // 获得返回结果
             HttpResponse response = client.execute(request);
             // 如果成功
             if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                 encode = StringUtils.isNotEmpty(encode) ? encode : DEFAULT_ENCODE;
                 result = EntityUtils.toString(response.getEntity(), encode);
             } else {
                 StringBuffer errorMsg = new StringBuffer();
                 errorMsg.append("httpStatus:");
                 errorMsg.append(response.getStatusLine().getStatusCode());
                 errorMsg.append(response.getStatusLine().getReasonPhrase());
                 errorMsg.append(", Header: ");
                 Header[] headers = response.getAllHeaders();
                 for (Header header : headers) {
                     errorMsg.append(header.getName());
                     errorMsg.append(":");
                     errorMsg.append(header.getValue());
                 }
                 logger.error("HttpResonse Error:" + errorMsg);
                 result = "{'Error':'98','Details':'" + errorMsg.toString() + "'}";
             }
         } catch (Exception e) {
             logger.error("http连接异常", e);
             throw new Exception("http连接异常");
         } finally {
             try {
                 client.getConnectionManager().shutdown();
             } catch (Exception e) {
                 logger.error("finally HttpClient shutdown error", e);
             }
         }
         return result;
     }  

四，总结

其实httpclient主要就是模仿浏览器来通过java代码调用另一个服务器或者应用的，其中最主要的就是url和参数，一般情况下都会用post带参的请求，有些情况下也有可能有抬头或者时间的这些额外的设置。