【JAVA】通过HttpClient发送HTTP请求的方法

HttpClient介绍

　　HttpClient 不是一个浏览器。它是一个客户端的 HTTP 通信实现库。HttpClient的目标是发 送和接收HTTP 报文。HttpClient不会去缓存内容，执行 嵌入在 HTML 页面中的javascript 代码，猜测内容类型，重新格式化请求/重定向URI，或者其它和 HTTP 运输无关的功能。

HttpClient使用

• 　　使用需要引入jar包，maven项目引入如下：

          <dependency>
              <groupId>org.apache.httpcomponents</groupId>
              <artifactId>httpclient</artifactId>
              <version>4.5</version>
          </dependency>
  
          <dependency>
              <groupId>org.apache.httpcomponents</groupId>
              <artifactId>httpcore</artifactId>
              <version>4.4.4</version>
          </dependency>
  
          <dependency>
              <groupId>org.apache.httpcomponents</groupId>
              <artifactId>httpmime</artifactId>
              <version>4.5</version>
          </dependency>

• 　　使用方法，代码如下：　

  package com.test;
  
  import java.io.File;
  import java.io.IOException;
  import java.security.KeyManagementException;
  import java.security.KeyStoreException;
  import java.security.NoSuchAlgorithmException;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.http.HttpEntity;
  import org.apache.http.HttpStatus;
  import org.apache.http.client.config.RequestConfig;
  import org.apache.http.client.methods.CloseableHttpResponse;
  import org.apache.http.client.methods.HttpGet;
  import org.apache.http.client.methods.HttpPost;
  import org.apache.http.config.Registry;
  import org.apache.http.config.RegistryBuilder;
  import org.apache.http.conn.socket.ConnectionSocketFactory;
  import org.apache.http.conn.socket.PlainConnectionSocketFactory;
  import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
  import org.apache.http.conn.ssl.SSLContextBuilder;
  import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
  import org.apache.http.entity.ContentType;
  import org.apache.http.entity.StringEntity;
  import org.apache.http.entity.mime.MultipartEntityBuilder;
  import org.apache.http.entity.mime.content.FileBody;
  import org.apache.http.entity.mime.content.StringBody;
  import org.apache.http.impl.client.CloseableHttpClient;
  import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
  import org.apache.http.impl.client.HttpClients;
  import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
  import org.apache.http.util.EntityUtils;
  
  /**
   * 
   * @author H__D
   * @date 2016年10月19日 上午11:27:25
   *
   */
  public class HttpClientUtil {
  
      // utf-8字符编码
      public static final String CHARSET_UTF_8 = "utf-8";
  
      // HTTP内容类型。
      public static final String CONTENT_TYPE_TEXT_HTML = "text/xml";
  
      // HTTP内容类型。相当于form表单的形式，提交数据
      public static final String CONTENT_TYPE_FORM_URL = "application/x-www-form-urlencoded";
  
      // HTTP内容类型。相当于form表单的形式，提交数据
      public static final String CONTENT_TYPE_JSON_URL = "application/json;charset=utf-8";
      
  
      // 连接管理器
      private static PoolingHttpClientConnectionManager pool;
  
      // 请求配置
      private static RequestConfig requestConfig;
  
      static {
          
          try {
              //System.out.println("初始化HttpClientTest~~~开始");
              SSLContextBuilder builder = new SSLContextBuilder();
              builder.loadTrustMaterial(null, new TrustSelfSignedStrategy());
              SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
                      builder.build());
              // 配置同时支持 HTTP 和 HTPPS
              Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory> create().register(
                      "http", PlainConnectionSocketFactory.getSocketFactory()).register(
                      "https", sslsf).build();
              // 初始化连接管理器
              pool = new PoolingHttpClientConnectionManager(
                      socketFactoryRegistry);
              // 将最大连接数增加到200，实际项目最好从配置文件中读取这个值
              pool.setMaxTotal(200);
              // 设置最大路由
              pool.setDefaultMaxPerRoute(2);
              // 根据默认超时限制初始化requestConfig
              int socketTimeout = 10000;
              int connectTimeout = 10000;
              int connectionRequestTimeout = 10000;
              requestConfig = RequestConfig.custom().setConnectionRequestTimeout(
                      connectionRequestTimeout).setSocketTimeout(socketTimeout).setConnectTimeout(
                      connectTimeout).build();
  
              //System.out.println("初始化HttpClientTest~~~结束");
          } catch (NoSuchAlgorithmException e) {
              e.printStackTrace();
          } catch (KeyStoreException e) {
              e.printStackTrace();
          } catch (KeyManagementException e) {
              e.printStackTrace();
          }
          
  
          // 设置请求超时时间
          requestConfig = RequestConfig.custom().setSocketTimeout(50000).setConnectTimeout(50000)
                  .setConnectionRequestTimeout(50000).build();
      }
  
      public static CloseableHttpClient getHttpClient() {
          
          CloseableHttpClient httpClient = HttpClients.custom()
                  // 设置连接池管理
                  .setConnectionManager(pool)
                  // 设置请求配置
                  .setDefaultRequestConfig(requestConfig)
                  // 设置重试次数
                  .setRetryHandler(new DefaultHttpRequestRetryHandler(0, false))
                  .build();
          
          return httpClient;
      }
  
      /**
       * 发送Post请求
       * 
       * @param httpPost
       * @return
       */
      private static String sendHttpPost(HttpPost httpPost) {
  
          CloseableHttpClient httpClient = null;
          CloseableHttpResponse response = null;
          // 响应内容
          String responseContent = null;
          try {
              // 创建默认的httpClient实例.
              httpClient = getHttpClient();
              // 配置请求信息
              httpPost.setConfig(requestConfig);
              // 执行请求
              response = httpClient.execute(httpPost);
              // 得到响应实例
              HttpEntity entity = response.getEntity();
  
              // 可以获得响应头
              // Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE);
              // for (Header header : headers) {
              // System.out.println(header.getName());
              // }
  
              // 得到响应类型
              // System.out.println(ContentType.getOrDefault(response.getEntity()).getMimeType());
  
              // 判断响应状态
              if (response.getStatusLine().getStatusCode() >= 300) {
                  throw new Exception(
                          "HTTP Request is not success, Response code is " + response.getStatusLine().getStatusCode());
              }
  
              if (HttpStatus.SC_OK == response.getStatusLine().getStatusCode()) {
                  responseContent = EntityUtils.toString(entity, CHARSET_UTF_8);
                  EntityUtils.consume(entity);
              }
  
          } catch (Exception e) {
              e.printStackTrace();
          } finally {
              try {
                  // 释放资源
                  if (response != null) {
                      response.close();
                  }
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
          return responseContent;
      }
  
      /**
       * 发送Get请求
       * 
       * @param httpGet
       * @return
       */
      private static String sendHttpGet(HttpGet httpGet) {
  
          CloseableHttpClient httpClient = null;
          CloseableHttpResponse response = null;
          // 响应内容
          String responseContent = null;
          try {
              // 创建默认的httpClient实例.
              httpClient = getHttpClient();
              // 配置请求信息
              httpGet.setConfig(requestConfig);
              // 执行请求
              response = httpClient.execute(httpGet);
              // 得到响应实例
              HttpEntity entity = response.getEntity();
  
              // 可以获得响应头
              // Header[] headers = response.getHeaders(HttpHeaders.CONTENT_TYPE);
              // for (Header header : headers) {
              // System.out.println(header.getName());
              // }
  
              // 得到响应类型
              // System.out.println(ContentType.getOrDefault(response.getEntity()).getMimeType());
  
              // 判断响应状态
              if (response.getStatusLine().getStatusCode() >= 300) {
                  throw new Exception(
                          "HTTP Request is not success, Response code is " + response.getStatusLine().getStatusCode());
              }
  
              if (HttpStatus.SC_OK == response.getStatusLine().getStatusCode()) {
                  responseContent = EntityUtils.toString(entity, CHARSET_UTF_8);
                  EntityUtils.consume(entity);
              }
  
          } catch (Exception e) {
              e.printStackTrace();
          } finally {
              try {
                  // 释放资源
                  if (response != null) {
                      response.close();
                  }
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
          return responseContent;
      }
      
      
      
      /**
       * 发送 post请求
       * 
       * @param httpUrl
       *            地址
       */
      public static String sendHttpPost(String httpUrl) {
          // 创建httpPost
          HttpPost httpPost = new HttpPost(httpUrl);
          return sendHttpPost(httpPost);
      }
  
      /**
       * 发送 get请求
       * 
       * @param httpUrl
       */
      public static String sendHttpGet(String httpUrl) {
          // 创建get请求
          HttpGet httpGet = new HttpGet(httpUrl);
          return sendHttpGet(httpGet);
      }
      
      
  
      /**
       * 发送 post请求（带文件）
       * 
       * @param httpUrl
       *            地址
       * @param maps
       *            参数
       * @param fileLists
       *            附件
       */
      public static String sendHttpPost(String httpUrl, Map<String, String> maps, List<File> fileLists) {
          HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
          MultipartEntityBuilder meBuilder = MultipartEntityBuilder.create();
          if (maps != null) {
              for (String key : maps.keySet()) {
                  meBuilder.addPart(key, new StringBody(maps.get(key), ContentType.TEXT_PLAIN));
              }
          }
          if (fileLists != null) {
              for (File file : fileLists) {
                  FileBody fileBody = new FileBody(file);
                  meBuilder.addPart("files", fileBody);
              }
          }
          HttpEntity reqEntity = meBuilder.build();
          httpPost.setEntity(reqEntity);
          return sendHttpPost(httpPost);
      }
  
      /**
       * 发送 post请求
       * 
       * @param httpUrl
       *            地址
       * @param params
       *            参数(格式:key1=value1&key2=value2)
       * 
       */
      public static String sendHttpPost(String httpUrl, String params) {
          HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
          try {
              // 设置参数
              if (params != null && params.trim().length() > 0) {
                  StringEntity stringEntity = new StringEntity(params, "UTF-8");
                  stringEntity.setContentType(CONTENT_TYPE_FORM_URL);
                  httpPost.setEntity(stringEntity);
              }
          } catch (Exception e) {
              e.printStackTrace();
          }
          return sendHttpPost(httpPost);
      }
  
      /**
       * 发送 post请求
       * 
       * @param maps
       *            参数
       */
      public static String sendHttpPost(String httpUrl, Map<String, String> maps) {
          String parem = convertStringParamter(maps);
          return sendHttpPost(httpUrl, parem);
      }
  
      
      
      
      /**
       * 发送 post请求 发送json数据
       * 
       * @param httpUrl
       *            地址
       * @param paramsJson
       *            参数(格式 json)
       * 
       */
      public static String sendHttpPostJson(String httpUrl, String paramsJson) {
          HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
          try {
              // 设置参数
              if (paramsJson != null && paramsJson.trim().length() > 0) {
                  StringEntity stringEntity = new StringEntity(paramsJson, "UTF-8");
                  stringEntity.setContentType(CONTENT_TYPE_JSON_URL);
                  httpPost.setEntity(stringEntity);
              }
          } catch (Exception e) {
              e.printStackTrace();
          }
          return sendHttpPost(httpPost);
      }
      
      /**
       * 发送 post请求 发送xml数据
       * 
       * @param httpUrl   地址
       * @param paramsXml  参数(格式 Xml)
       * 
       */
      public static String sendHttpPostXml(String httpUrl, String paramsXml) {
          HttpPost httpPost = new HttpPost(httpUrl);// 创建httpPost
          try {
              // 设置参数
              if (paramsXml != null && paramsXml.trim().length() > 0) {
                  StringEntity stringEntity = new StringEntity(paramsXml, "UTF-8");
                  stringEntity.setContentType(CONTENT_TYPE_TEXT_HTML);
                  httpPost.setEntity(stringEntity);
              }
          } catch (Exception e) {
              e.printStackTrace();
          }
          return sendHttpPost(httpPost);
      }
      
  
      /**
       * 将map集合的键值对转化成：key1=value1&key2=value2 的形式
       * 
       * @param parameterMap
       *            需要转化的键值对集合
       * @return 字符串
       */
      public static String convertStringParamter(Map parameterMap) {
          StringBuffer parameterBuffer = new StringBuffer();
          if (parameterMap != null) {
              Iterator iterator = parameterMap.keySet().iterator();
              String key = null;
              String value = null;
              while (iterator.hasNext()) {
                  key = (String) iterator.next();
                  if (parameterMap.get(key) != null) {
                      value = (String) parameterMap.get(key);
                  } else {
                      value = "";
                  }
                  parameterBuffer.append(key).append("=").append(value);
                  if (iterator.hasNext()) {
                      parameterBuffer.append("&");
                  }
              }
          }
          return parameterBuffer.toString();
      }
  
      public static void main(String[] args) throws Exception {
          
          System.out.println(sendHttpGet("http://www.baidu.com"));
      
      }
  }