废话不多说，直接上代码

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
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.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 com.pingan.qhcs.map.audit.constant.CodeConstant;
import com.pingan.qhcs.map.audit.exception.MapException;

public class HttpClientUtil {

 protected static Log logger = LogFactory.getLog(HttpClientUtil.class);
 
 private static PoolingHttpClientConnectionManager cm;
 private static String EMPTY_STR = "";
 private static String UTF_8 = "UTF-8";

 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
  }
 }

 /**
  * 通过连接池获取HttpClient
  * 
  * @return
  */
 public static CloseableHttpClient getHttpClient() {
  init();
  return HttpClients.custom().setConnectionManager(cm).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, 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, UTF_8));

  return getResult(httpPost);
 }

 public static String httpPostRequest(String url, Map<String, Object> headers, String strBody)
   throws Exception {
  HttpPost httpPost = new HttpPost(url);

  for (Map.Entry<String, Object> param : headers.entrySet()) {
   httpPost.addHeader(param.getKey(), String.valueOf(param.getValue()));
  }
  httpPost.setEntity(new StringEntity(strBody, UTF_8));
  return getResult(httpPost);
 }
 
 private static ArrayList<NameValuePair> covertParams2NVPS(Map<String, Object> params) {
  ArrayList<NameValuePair> pairs = new ArrayList<NameValuePair>();
  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
  * 
  * setConnectTimeout：设置连接超时时间，单位毫秒。
  * setConnectionRequestTimeout：设置从connect Manager获取Connection 超时时间，单位毫秒。这个属性是新加的属性，因为目前版本是可以共享连接池的。
  * setSocketTimeout：请求获取数据的超时时间，单位毫秒。 如果访问一个接口，多少时间内无法返回数据，就直接放弃此次调用。
  * 
  * @param request
  * @return
  */
 private static String getResult(HttpRequestBase request) {
  
  RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(60000)
    .setConnectionRequestTimeout(5000).setSocketTimeout(60000).build();
  request.setConfig(requestConfig);// 设置请求和传输超时时间

  // CloseableHttpClient httpClient = HttpClients.createDefault();
  CloseableHttpClient httpClient = getHttpClient();
  try {
   CloseableHttpResponse response = httpClient.execute(request); //执行请求
   // response.getStatusLine().getStatusCode();
   HttpEntity entity = response.getEntity();
   if (entity != null) {
    // long len = entity.getContentLength();// -1 表示长度未知
    String result = EntityUtils.toString(entity);
    response.close();
    // httpClient.close();
    return result;
   }
  } catch (ClientProtocolException e) {
   logger.error("[maperror] HttpClientUtil ClientProtocolException : " + e.getMessage());
   throw new MapException(CodeConstant.CODE_CONNECT_FAIL, "HttpClientUtil ClientProtocolException ：" + e.getMessage());
  } catch (IOException e) {
   logger.error("[maperror] HttpClientUtil IOException : " + e.getMessage());
   throw new MapException(CodeConstant.CODE_CONNECT_FAIL, "HttpClientUtil IOException ：" + e.getMessage());
  } finally {

  }
  return EMPTY_STR;
 }

}