[英]HTTP connection pooling using HttpClient
I am developing in Java, using Apache HTTP Client .我正在 Java 中开发,使用Apache HTTP Client 。
I have spent recent days working on this so just want to share some "everyone-known" knowledges with you.我最近几天都在研究这个,所以只想与您分享一些“人人皆知”的知识。
First, as you are dealing with the same server, it is recommended to use a single HTTP client to execute your requests.首先,当您处理同一台服务器时,建议使用单个 HTTP 客户端来执行您的请求。 With the help of
PoolingHttpClientConnectionManager
, your client can be used to execute multiple requests concurrently.在
PoolingHttpClientConnectionManager
的帮助下,您的客户端可用于同时执行多个请求。 The official example of multithreaded request execution can be found here .多线程请求执行的官方示例可以在这里找到。
Secondly, HTTP/1.1 (and enhanced versions of HTTP/1.0) allows HTTP clients to keep the connections open after transactions complete so that it can be reused for future requests.其次,HTTP/1.1(和 HTTP/1.0 的增强版本)允许 HTTP 客户端在事务完成后保持连接打开,以便它可以被重用于未来的请求。 This is often refered as Persistent Connection .
这通常被称为持久连接。
Also for the purpose of reusing client for multiple requests, the response header from a server often include an attribute call Keep-Alive
that contain the time current connection will be kept alive.同样为了对多个请求重用客户端,来自服务器的响应头通常包含一个属性调用
Keep-Alive
,其中包含当前连接将保持活动的时间。 Besides that, Apache Http Client also provides you an interface ConnectionKeepAliveStrategy
to customize your own policy for reusing connection.除此之外,Apache Http Client 还为您提供了一个接口
ConnectionKeepAliveStrategy
来自定义您自己的重用连接策略。
PoolingClientConnectionManager
is Deprecated now . PoolingClientConnectionManager
现在已弃用。 from (4.3 version) use PoolingHttpClientConnectionManager
.从(4.3 版)使用
PoolingHttpClientConnectionManager
。
[assuming Java, and Apache's HttpClient] [假设 Java 和 Apache 的 HttpClient]
Use a ThreadSafeClientConnManager .使用ThreadSafeClientConnManager 。 Pass a single global instance to the constructor of every HttpClient instance.
将单个全局实例传递给每个 HttpClient 实例的构造函数。 I don't think there's any point in pooling the HttpClients themselves.
我认为将 HttpClient 本身集中起来没有任何意义。
ThreadSafeClientConnManager 现在已弃用,请改用PoolingClientConnectionManager 。
For HttpClient 4x:对于 HttpClient 4x:
ThreadSafeClientConnManager ... manages a pool of client connections and is able to service connection requests from multiple execution threads.
ThreadSafeClientConnManager ... 管理客户端连接池,并能够为来自多个执行线程的连接请求提供服务。
Connections are pooled on a per route basis .
连接在每个路由的基础上汇集。 A request for a route for which the manager already has a persistent connection available in the pool will be serviced by leasing a connection from the pool rather than creating a brand new connection.
对于管理器已经在池中具有可用持久连接的路由的请求,将通过从池中租用连接而不是创建全新的连接来提供服务。
http://hc.apache.org/httpcomponents-client-ga/tutorial/html/connmgmt.html http://hc.apache.org/httpcomponents-client-ga/tutorial/html/connmgmt.html
This is an example of an Apache HttpClient 4.3 pool of connections which do not require authentication:这是不需要身份验证的 Apache HttpClient 4.3 连接池的示例:
public class PoolOfHttpConnections{
static String[] urisToGet = {"http://www.site1.com", "http://www.site2.com"};
public static void main(String[] args) throws Exception {
CloseableHttpClient httpclient = HttpClients.createDefault();
// create a thread for each link
GetThread[] threads = new GetThread[urisToGet.length];
for (int i = 0; i < threads.length; i++) {
HttpGet httpget = new HttpGet(urisToGet[i]);
threads[i] = new GetThread(httpClient, httpget);
}
// start the threads
for (int j = 0; j < threads.length; j++) {
threads[j].start();
}
// join the threads
for (int j = 0; j < threads.length; j++) {
threads[j].join();
}
} //end main
private static class GetThread extends Thread {
private final CloseableHttpClient httpClient;
private final HttpContext context;
private final HttpGet httpget;
public GetThread(CloseableHttpClient httpClient, HttpGet httpget) {
this.httpClient = httpClient;
this.context = HttpClientContext.create();
this.httpget = httpget;
}
@Override
public void run() {
try {
CloseableHttpResponse response = httpClient.execute(httpget, context);
try {
HttpEntity entity = response.getEntity();
System.out.println("----------------------------------------");
Date date = new Date();
System.out.println("Beginning*******************");
System.out.println(date.toString());
System.out.println("There are "+urisToGet.length+" threads running in parallel!");
System.out.println(response.getStatusLine());
if (entity != null) {
System.out.println("Response content length: " + entity.getContentLength());
}
System.out.println(EntityUtils.toString(entity));
EntityUtils.consume(entity);
} finally {
response.close();
System.out.println("End*******************");
}
} catch (ClientProtocolException ex) {
// Handle protocol errors
} catch (IOException ex) {
// Handle I/O errors
}
}
} /*end private class*/ }//end public class PoolOfHttpConnections
HttpClient has already have a connection pool.So you do not need to create it. HttpClient 已经有一个连接池,所以你不需要创建它。 Just use it.
就用它。
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