【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"));
  
       }
   }