If using Apache's HttpClient, you can create a custom DNS resolver to detect the host you'd like to redirect, and then provide a substitute IP address.
Note: Just changing the Host header for HTTPS requests doesn't work. It will
throw "javax.net.ssl.SSLPeerUnverifiedException", forcing you to trust bad
certificates, stop SNI from working, etc., so really not an option. A
custom DnsResolver is the only clean way I've found to get these requests to work
with HTTPS in Java.
Example:
/* Custom DNS resolver */
DnsResolver dnsResolver = new SystemDefaultDnsResolver() {
@Override
public InetAddress[] resolve(final String host) throws UnknownHostException {
if (host.equalsIgnoreCase("my.host.com")) {
/* If we match the host we're trying to talk to,
return the IP address we want, not what is in DNS */
return new InetAddress[] { InetAddress.getByName("127.0.0.1") };
} else {
/* Else, resolve it as we would normally */
return super.resolve(host);
}
}
};
/* HttpClientConnectionManager allows us to use custom DnsResolver */
BasicHttpClientConnectionManager connManager = new BasicHttpClientConnectionManager(
/* We're forced to create a SocketFactory Registry. Passing null
doesn't force a default Registry, so we re-invent the wheel. */
RegistryBuilder.<ConnectionSocketFactory>create()
.register("http", PlainConnectionSocketFactory.getSocketFactory())
.register("https", SSLConnectionSocketFactory.getSocketFactory())
.build(),
null, /* Default ConnectionFactory */
null, /* Default SchemePortResolver */
dnsResolver /* Our DnsResolver */
);
/* build HttpClient that will use our DnsResolver */
HttpClient httpClient = HttpClientBuilder.create()
.setConnectionManager(connManager)
.build();
/* build our request */
HttpGet httpRequest = new HttpGet("https://my.host.com/page?and=stuff");
/* Executing our request should now hit 127.0.0.1, regardless of DNS */
HttpResponse httpResponse = httpClient.execute(httpRequest);
