为什么我的 HTTPPost 会收到 404 响应？

Question

I'm using org.apache.http.client.methods.HttpPost to send data to a verified URL. My client works on some systems but not others. I've verified the URL I'm attempting to access from my JAVA code is accessible from the client's systems using a web browser. The really strange thing is there is no record of the POST coming into Tomcat when I review the Tomcat access logs.

My only guess at this point is the client side systems are using some type of application level firewall. I'm still looking into that possibility.

Can anyone think of any other possible reasons why I'd be getting a 404 response without a record of the request in the Tomcat 8 access logs?

Thanks!

Answer 1

I figured it out about an hour after I posted this question. Our System Administrator updated the DNS record the HTTP clients were attempting to connect to. The DNS update pointed to a Application server that did not host the webapp the client was trying to communicate with.

While the DNS record was invalid he restarted all of the HTTP client services and when they tried to connect to the webapp the clients got a 404 response.

Once I figured out there was something wrong with the DNS record and had him correct the IP that's when we started seeing the topic in question.

It turns out when the HTTPClient receives a 404 response, it no longer attempts to bind to the URL until the client service is restarted or a new HTTPClient instance is created.

Here's my client code...

CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials("UN", "PW"));         
HttpClient client = HttpClientBuilder.create().setDefaultCredentialsProvider(credentialsProvider).build();

Can someone provide me with sample code to force the org.apache.http.client.HttpClient to check for a resource despite any prior 404 responses?