Apache HTTP客户端只能有两个连接 [英] Apache HTTP client only two connections are possible

问题描述

我有以下代码来使用Apache HTTP客户端调用REST API方法。但是，只能使用上述客户端发送两个并行请求。
是否有设置max-connections的参数？

I have below code to invoke a REST API method using Apache HTTP client. However only two parallel requests could be sent using above client. Is there any parameter to set max-connections?

     HttpPost post = new HttpPost(resourcePath);
            addPayloadJsonString(payload, post);//set a String Entity
            setAuthHeader(post);// set Authorization: Basic header
            try {
                return httpClient.execute(post);

            } catch (IOException e) {
                String errorMsg = "Error while executing POST statement";
                log.error(errorMsg, e);


  throw new RestClientException(errorMsg, e);
        }

我正在使用的罐子是，

org.apache.httpcomponents.httpclient_4.3.5.jar
org.apache.httpcomponents.httpcore_4.3.2.jar

推荐答案

您可以使用 HttpClientConnectionManager

You can configure the HttpClient with HttpClientConnectionManager

看看池化连接管理器。

ClientConnectionPoolManager 维护一个 HttpClientConnections ，可以为来自的连接请求提供服务多个执行线程。连接以每个路由为基础进行池化。对于已经管理器具有池中可用连续连接的路由的请求将是通过从池租用连接而不是创建全新连接的服务。

ClientConnectionPoolManager maintains a pool of HttpClientConnections and is able to service connection requests from multiple execution threads. Connections are pooled on a per route basis. A request for a route which already the manager has persistent connections for available in the pool will be services by leasing a connection from the pool rather than creating a brand new connection.

PoolingHttpClientConnectionManager 维持每个路由和总计的最大连接数限制。默认情况下，此实现将为每个给定路由创建不超过2个并发连接，并且总共不再有20个连接。对于许多实际应用程序，这些限制可能过于严格，特别是如果他们使用HTTP作为其服务的传输协议。

PoolingHttpClientConnectionManager maintains a maximum limit of connections on a per route basis and in total. Per default this implementation will create no more than 2 concurrent connections per given route and no more 20 connections in total. For many real-world applications these limits may prove too constraining, especially if they use HTTP as a transport protocol for their services.

示例显示了如何调整连接池参数：

This example shows how the connection pool parameters can be adjusted:

PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
// Increase max total connection to 200
cm.setMaxTotal(200);
// Increase default max connection per route to 20
cm.setDefaultMaxPerRoute(20);
// Increase max connections for localhost:80 to 50
HttpHost localhost = new HttpHost("locahost", 80);
cm.setMaxPerRoute(new HttpRoute(localhost), 50);

CloseableHttpClient httpClient = HttpClients.custom()
        .setConnectionManager(cm)
        .build();

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