httpclient4.x 使用连接池发送https请求使用总结

    由于项目中需要用httpclient进行内部服务请求处理，但之前没有是用httpclient中提供的连接池，而是自己封装的一个类似池的结构，一段时间后产生了性能问题，转而尝试通过是用httpclient内部的池进行处理，而且需要支持https的连接。

     所使用的httpclient的版本为4.4.1，一共用到了三个jar：httpclient-4.4.1.jar、httpclient-cache-4.4.1.jar、httpcore-4.4.1.jar。

    所使用的连接池管理器的类为PoolingHttpClientConnectionManager，但httpclient部分参数，包括池的大小，最大路由，缓存，超时这些参数还未做深入研究；

     上代码：

      

  初始化代码：
     public void init()
 {
   try {
   //需要通过以下代码声明对https连接支持
   SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(null,
                   new TrustSelfSignedStrategy())
           .build();
   HostnameVerifier hostnameVerifier = SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER;
   SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
           sslcontext,hostnameVerifier);
   Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory>create()
           .register("http", PlainConnectionSocketFactory.getSocketFactory())
           .register("https", sslsf)
           .build();
   //初始化连接管理器
   poolConnManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
   // Increase max total connection to 200
   poolConnManager.setMaxTotal(maxTotalPool);
   // Increase default max connection per route to 20
   poolConnManager.setDefaultMaxPerRoute(maxConPerRoute);
  } catch (KeyManagementException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (NoSuchAlgorithmException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (KeyStoreException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
//获取连接
 public CloseableHttpClient getConnection()
 {
      CloseableHttpClient httpClient = HttpClients.custom()
.setConnectionManager(poolConnManager).build(); 
      return httpClient;
 }
//发送请求 url为请求url，jsonstr为请求参数
public String post(String url, String jsonStr)
 {
  String returnStr = null;
  //参数检测
  if(url==null||"".equals(url))
  {
   return returnStr;
  }
  try {
   HttpPost httpPost = new HttpPost(url);
   List <NameValuePair> nvps = new ArrayList <NameValuePair>();
   //设置post参数对
   nvps.add(new BasicNameValuePair("jsonstr", jsonStr));
   //设置编码，如果包含中文，一定要进行设置，否则按照系统默认字符集进行转码会出现乱码
   httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
   CloseableHttpResponse response = client.execute(httpPost);
   //获取响应状态码
   int status = response.getStatusLine().getStatusCode();
            if (status >= 200 && status < 300) {
                HttpEntity entity = response.getEntity();
                return entity != null ? EntityUtils.toString(entity,"utf-8") : null;
            } else {
                throw new ClientProtocolException("Unexpected response status: " + status);
            }
  } catch (UnsupportedEncodingException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (ClientProtocolException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  //相应返回值
  return returnStr;
 }

 -------------------------------------------分隔线------------------------------------------------------

  在使用上述代码一段时间后，出现了tomcat异常后死掉的bug，而且是随机出现，没有找到具体原因，最终在加了一堆日志后，分析得知是因为在返回状态码非200的时候，httpclient的连接不会自动断开，需要手工断开，否则在连接达到pool的最大值后，无可用连接，最终导致tomcat死掉。

最后修改的代码如下：

public void init()
	{
		 try {
			SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(null,
			                new TrustSelfSignedStrategy())
			        .build();
			HostnameVerifier hostnameVerifier = SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER;
			SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
			        sslcontext,hostnameVerifier);
			Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory>create()
			        .register("http", PlainConnectionSocketFactory.getSocketFactory())
			        .register("https", sslsf)
			        .build();
			poolConnManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
			// Increase max total connection to 200
			poolConnManager.setMaxTotal(maxTotalPool);
			// Increase default max connection per route to 20
			poolConnManager.setDefaultMaxPerRoute(maxConPerRoute);
			SocketConfig socketConfig = SocketConfig.custom().setSoTimeout(socketTimeout).build();
			poolConnManager.setDefaultSocketConfig(socketConfig);
		} catch (Exception e) {
			log.error("InterfacePhpUtilManager init Exception"+e.toString());
		}
	}
	public CloseableHttpClient getConnection()
	{
		RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(connectionRequestTimeout)
				.setConnectTimeout(connectTimeout).setSocketTimeout(socketTimeout).build();
		CloseableHttpClient httpClient = HttpClients.custom()
			        .setConnectionManager(poolConnManager).setDefaultRequestConfig(requestConfig).build();
		if(poolConnManager!=null&&poolConnManager.getTotalStats()!=null)
		{
			log.info("now client pool "+poolConnManager.getTotalStats().toString());
		}
		return httpClient;
	}

  其中输出的连接一共有四个状态，是需要时时关注的，可以作为调整参数的依据，具体含义为：

 

leased ：the number of persistent connections tracked by the connection manager currently being used to execute requests.

available ：the number idle persistent connections.

pending : the number of connection requests being blocked awaiting a free connection.

max: the maximum number of allowed persistent connections.

    

   需要特别关注pending和leased的值，如果leased的值特别大，接近max，则需要修改max，如果pending的值也比较大，也需要调整max，并考虑设置timeout，可以设置两个timeout，一个是获取连接的timeout，另外一个是获取socket数据的timeout。代码中已经有相关示例了。

 具体获取响应时，要改为如下代码，即在返回的状态码不是200时，要主动关闭连接

public String postPhp(String url, String jsonStr)
	{
		String returnStr = null;
		//参数检测
		if(url==null||"".equals(url))
		{
			return returnStr;
		}
		HttpPost httpPost = new HttpPost(url);
		try {
			
			long currentTime=System.currentTimeMillis();
			List <NameValuePair> nvps = new ArrayList <NameValuePair>();
			nvps.add(new BasicNameValuePair("jsonstr", jsonStr));
			httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
			sysoutLog(currentTime+" 开始发送 请求：url"+url);
			CloseableHttpResponse response = client.execute(httpPost);
			int status = response.getStatusLine().getStatusCode();
            if (status >= 200 && status < 300) {
            	HttpEntity entity = response.getEntity();
                String resopnse="";
                if(entity != null)
                {
                	resopnse=EntityUtils.toString(entity,"utf-8");
                }
                sysoutLog(currentTime+" 接收响应：url"+url+" status="+status);
                return entity != null ? resopnse : null;
            } else {
            	HttpEntity entity = response.getEntity();
            	httpPost.abort();
            	sysoutLog(currentTime+" 接收响应：url"+url+" status="+status+" resopnse="+EntityUtils.toString(entity,"utf-8"));
                throw new ClientProtocolException("Unexpected response status: " + status);
            }
		} catch (Exception e) {
			httpPost.abort();
			log.error(" Exception"+e.toString()+" url="+url+" jsonstr="+jsonStr);
		} 
		return returnStr;
	}