spring boot中使用http请求的示例代码

private static HttpClient client = null; 
static { 
PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager(); 
cm.setMaxTotal(128);
cm.setDefaultMaxPerRoute(128);
client = HttpClients.custom().setConnectionManager(cm).build(); 
}

//根据request获取请求的url
public StringBuffer getUrlToRequest(HttpServletRequest request) { 
StringBuffer url=request.getRequestURL();//获取请求的url(http://localhost:8080/switch/getStudentInfoByName) 
String[] splitArr=url.toString().split("/"); 
String appName=splitArr[3];//项目名称 
String ipReport=splitArr[2];//项目ip:report 
String resultStr=url.toString().replaceAll(appName,DevFacConstans.facname).replaceAll(ipReport, DevFacConstans.ip+":"+DevFacConstans.report); 
return new StringBuffer(resultStr); 
}

/**
* 发送http请求 有request
* 给controller层调用
* @param request 
* @return 
*/
public String sendHttpToDevFac(HttpServletRequest request)throws Exception { 
HttpClient client = null; 
String returnResult=""; 
// http://localhost:8080/leo/1.0/h5/login 
StringBuffer urlBuffer=getUrlToRequest(request);//调用第二步，获取url 
//获取参数并拼装
String dataAsJson = request.getParameter("data"); 
String encoderData=URLEncoder.encode(dataAsJson,"utf-8"); 
HttpGet get=new HttpGet(urlBuffer.append("?data=").append(encoderData).toString()); 
//set headers
Enumeration<String> headerNames=request.getHeaderNames(); 
while(headerNames.hasMoreElements()) {
String headerName=headerNames.nextElement(); 
String headerValue=request.getHeader(headerName); 
get.setHeader(headerName, headerValue); 
}
client=DeviceFactoryHttp.client;
logger.info("开始调用http请求，请求url:"+urlBuffer.toString());
HttpResponse rep=client.execute(get); 
returnResult=EntityUtils.toString(rep.getEntity(),"utf-8");
logger.info("http 请求调用结束!!");
return returnResult; 
}

/**
* 获取request
* @return 
*/
public static HttpServletRequest getRequest(){ 
 ServletRequestAttributes ra= (ServletRequestAttributes) RequestContextHolder.getRequestAttributes(); 
 HttpServletRequest request = ra.getRequest(); 
 return request; 
}

/**
 * 没有request 请求，给controller层调用
 * @param key
 * @param interfaceName
 * @param strings
 * @return
 * @throws Exception
 */
 public String centerToDeviceFacNoRequest(String key,String interfaceName)throws Exception {
 try {
  HttpServletRequest request=getRequest();//上面第一步，从上下文中获取url
  //获取reuquest请求参数
  Enumeration<String> names= request.getParameterNames();
  Map<String,String>paramMap=new HashMap<>();
  //遍历请求map
  while(names.hasMoreElements()) {
   String name=names.nextElement();
   String value=(String) request.getParameter(name);
   paramMap.put(name, value);
  }
  //调用发送http请求的方法
  return sendHttpToDevFacNoData(paramMap,request);
 } catch (Exception e) {
  e.printStackTrace();
 }
 //end
 return null;
 }

/**
 * 发送http请求，【没有data数据的】
 * @return
 */
 public String sendHttpToDevFacNoData(Map<String,String>paramMap,HttpServletRequest request)throws Exception {
 HttpClient client = null;
 String result="";
 StringBuffer dataBuffer=getUrlToRequest(request);//获取url
 dataBuffer.append("?");
 client=DeviceFactoryHttp.client;
 Iterator<Entry<String, String>> paamIt=paramMap.entrySet().iterator();
 while(paamIt.hasNext()) {
  Entry<String, String> entry=paamIt.next();
  dataBuffer.append(entry.getKey()).append("=").append(entry.getValue()).append("&");
 }
 String resultUrl=dataBuffer.toString().substring(0, dataBuffer.toString().lastIndexOf("&"));
 //发送请求
 HttpGet get=new HttpGet(resultUrl);
 //set headers
 Enumeration<String> headerNames=request.getHeaderNames();
 while(headerNames.hasMoreElements()) {
  String headerName=headerNames.nextElement();
  String headerValue=request.getHeader(headerName);
  get.setHeader(headerName, headerValue);
 }

 HttpResponse rep=client.execute(get);
 logger.info("开始调用http请求，请求url:"+resultUrl);
 //返回结果
 result=EntityUtils.toString(rep.getEntity(),"utf-8");
 logger.info(" http 请求调用结束!!");
 return result;
 }