httpclient4.x 使用连接池发送https请求

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;
}