Simply by configuration you can setup Jetty to provide a SPDY connector where clients can connect to via SPDY and will be transparently proxied to a target host speaking SPDY as well or another web protocol.
Here’s some details about the internals. The implementation is modular and can easily be extended. There’s a HTTPSPDYProxyConnector that accepts incoming requests and forwards them to a ProxyEngineSelector. ProxyEngineSelector will forward the request to an appropiate ProxyEngine for the given target host protocol.
Which ProxyEngine to use is determined by the configured ProxyServerInfos which hold the information about known target hosts and the protocol they speak.
Up to now we only have a ProxyEngine implementation for SPDY. But implementing other protocols like HTTP should be pretty straight forward and will follow. Contributions are like always highly welcome!
https://www.webtide.com is already served through a proxy connector forwarding to a plain SPDY connector on localhost.
For more details and an example configuration check the SPDY proxy documentation out.