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;
     }

 }