org.apache.httpcomponents:httpclient 工具类

基于httpclient 版本4.4.1

因为http连接需要三次握手，在需要频繁调用时浪费资源和时间

故采用连接池的方式连接

　　根据实际需要更改  连接池最大连接数、路由最大连接数

　　另一个需要注意的是

　　　// 释放Socket流

     response.close();

     // 释放Connection

     // httpClient.close();

 import org.apache.http.HttpEntity;

 import org.apache.http.NameValuePair;

 import org.apache.http.client.config.RequestConfig;

 import org.apache.http.client.entity.UrlEncodedFormEntity;

 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.client.methods.HttpRequestBase;

 import org.apache.http.client.utils.URIBuilder;

 import org.apache.http.config.SocketConfig;

 import org.apache.http.entity.StringEntity;

 import org.apache.http.impl.client.CloseableHttpClient;

 import org.apache.http.impl.client.HttpClients;

 import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;

 import org.apache.http.message.BasicNameValuePair;

 import org.apache.http.util.EntityUtils;

 import java.io.IOException;

 import java.io.UnsupportedEncodingException;

 import java.net.URISyntaxException;

 import java.util.ArrayList;

 import java.util.Map;

 /**

  * Created by lidada on 2017/6/9.

  */

 public class HttpClientUtils {

     private static PoolingHttpClientConnectionManager cm;

     private static String EMPTY_STR = "";

     private static String CONTENT_TYPE_UTF_8 = "UTF-8";

     private static String CONTENT_TYPE_GBK = "GBK";

     private static String CONTENT_TYPE_JSON = "application/json";

     private static final int CONNECTION_TIMEOUT_MS = 60000;

     private static final int SO_TIMEOUT_MS = 60000;

     private static void init() {

         if (cm == null) {

             cm = new PoolingHttpClientConnectionManager();

             cm.setMaxTotal(50);// 整个连接池最大连接数

             cm.setDefaultMaxPerRoute(5);// 每路由最大连接数，默认值是2

             SocketConfig sc = SocketConfig.custom().setSoTimeout(SO_TIMEOUT_MS).build();

             cm.setDefaultSocketConfig(sc);

         }

     }

     /**

      * 通过连接池获取HttpClient

      *

      * @return

      */

     private static CloseableHttpClient getHttpClient() {

         init();

         return HttpClients.custom().setConnectionManager(cm).setConnectionManagerShared(true) .build();

     }

     public static String httpGetRequest(String url) {

         HttpGet httpGet = new HttpGet(url);

         return getResult(httpGet);

     }

     public static String httpGetRequest(String url, Map<String, Object> params) throws URISyntaxException {

         URIBuilder ub = new URIBuilder();

         ub.setPath(url);

         ArrayList<NameValuePair> pairs = covertParams2NVPS(params);

         ub.setParameters(pairs);

         HttpGet httpGet = new HttpGet(ub.build());

         return getResult(httpGet);

     }

     public static String httpGetRequest(String url, Map<String, Object> headers, Map<String, Object> params)

             throws URISyntaxException {

         URIBuilder ub = new URIBuilder();

         ub.setPath(url);

         ArrayList<NameValuePair> pairs = covertParams2NVPS(params);

         ub.setParameters(pairs);

         HttpGet httpGet = new HttpGet(ub.build());

         for (Map.Entry<String, Object> param : headers.entrySet()) {

             httpGet.addHeader(param.getKey(), String.valueOf(param.getValue()));

         }

         return getResult(httpGet);

     }

     public static String httpPostRequest(String url) {

         HttpPost httpPost = new HttpPost(url);

         return getResult(httpPost);

     }

     public static String httpPostRequest(String url, Map<String, Object> params) throws UnsupportedEncodingException {

         HttpPost httpPost = new HttpPost(url);

         ArrayList<NameValuePair> pairs = covertParams2NVPS(params);

         httpPost.setEntity(new UrlEncodedFormEntity(pairs, CONTENT_TYPE_UTF_8));

         return getResult(httpPost);

     }

     public static String httpPostRequest(String url, Map<String, Object> headers, Map<String, Object> params)

             throws UnsupportedEncodingException {

         HttpPost httpPost = new HttpPost(url);

         for (Map.Entry<String, Object> param : headers.entrySet()) {

             httpPost.addHeader(param.getKey(), String.valueOf(param.getValue()));

         }

         ArrayList<NameValuePair> pairs = covertParams2NVPS(params);

         httpPost.setEntity(new UrlEncodedFormEntity(pairs, CONTENT_TYPE_UTF_8));

         return getResult(httpPost);

     }

     public static String httpPostJSON(String url, String json) throws UnsupportedEncodingException {

         HttpPost httpPost = new HttpPost(url);

         StringEntity s = new StringEntity(json);

         s.setContentEncoding(CONTENT_TYPE_UTF_8);

         s.setContentType(CONTENT_TYPE_JSON);// 发送json数据需要设置contentType

         httpPost.setEntity(s);

         return getResult(httpPost);

     }

     private static ArrayList<NameValuePair> covertParams2NVPS(Map<String, Object> params) {

         ArrayList<NameValuePair> pairs = new ArrayList<>();

         for (Map.Entry<String, Object> param : params.entrySet()) {

             pairs.add(new BasicNameValuePair(param.getKey(), String.valueOf(param.getValue())));

         }

         return pairs;

     }

     /**

      * 处理Http请求

      *

      * @param request

      * @return

      */

     private static String getResult(HttpRequestBase request) {

         RequestConfig.Builder config = RequestConfig.copy(RequestConfig.DEFAULT);

         config.setConnectionRequestTimeout(CONNECTION_TIMEOUT_MS);

         config.setSocketTimeout(SO_TIMEOUT_MS);

         request.setConfig(config.build());

         // CloseableHttpClient httpClient = HttpClients.createDefault();

         CloseableHttpClient httpClient = getHttpClient();

         CloseableHttpResponse response = null;

         try {

             response = httpClient.execute(request);

             // response.getStatusLine().getStatusCode();

             HttpEntity entity = response.getEntity();

             if (entity != null) {

                 // long len = entity.getContentLength();// -1 表示长度未知

                 return EntityUtils.toString(entity);

             }

         } catch (IOException e) {

             e.printStackTrace();

         } finally {

             try {

                 // 释放Socket流

                 response.close();

                 // 释放Connection

                 // httpClient.close();

             } catch (IOException e) {

                 e.printStackTrace();

             }

         }

         return EMPTY_STR;

     }

 }