CODEWITHSUNDEEP
javaapache-httpclient-4.xapache-httpcomponents
lanoxx
lanoxx

Reputation: 13051

Apache HttpComponents BasicHttpClientConnectionManager

I recently switched from java.net to org.apache.http.client, I have setup a ClosableHttpClient with the HttpClientBuilder. As connection manager I am using the BasicHttpClientConnectionManager.

Now I have the problem that very often when I create some HTTP request I get a timeout exception. It seems that the connection manager is keeping connections open to reuse them but if the system is idle for a few minutes then this connection will timeout and when I make the next request the first thing I get is a timeout. Repeating the same request one more time then usually works without any problem.

Is there a way to configure the BasicHttpClientConnectionManager in order to not reuse its connections and create a new connection each time?

Upvotes: 1

Views: 2639

Answers (1)

ok2c
ok2c

Reputation: 27538

There several ways of dealing with the problem

  1. Evict idle connections once no longer needed. The code below effectively disables connection persistence by closing out persistent connections after each HTTP exchange. 

    BasicHttpClientConnectionManager cm = new BasicHttpClientConnectionManager();
CloseableHttpClient httpclient = HttpClients.custom().setConnectionManager(cm).build();
...
try (CloseableHttpResponse response = httpclient.execute(new HttpGet("/"))) {
    System.out.println(response.getStatusLine());
    EntityUtils.consume(response.getEntity());
}
cm.closeIdleConnections(0, TimeUnit.MILLISECONDS);

  2. Limit connection keep-alive time to something relatively small-ish

    BasicHttpClientConnectionManager cm = new BasicHttpClientConnectionManager();
CloseableHttpClient httpclient = HttpClients.custom()
        .setConnectionManager(cm)
        .setKeepAliveStrategy((response, context) -> 1000)
        .build();
try (CloseableHttpResponse response = httpclient.execute(new HttpGet("/"))) {
    System.out.println(response.getStatusLine());
    EntityUtils.consume(response.getEntity());
}

  3. (Recommended) Use pooling connection manager and set connection total time to live to a finite value. There are no benefits to using the basic connection manager compared to the pooling one unless your code is expected to run in an EJB container.

    CloseableHttpClient httpclient = HttpClients.custom()
        .setConnectionTimeToLive(5, TimeUnit.SECONDS)
        .build();
try (CloseableHttpResponse response = httpclient.execute(new HttpGet("/"))) {
    System.out.println(response.getStatusLine());
    EntityUtils.consume(response.getEntity());
}

Upvotes: 1

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