How to generate Java client proxy for RESTful service implemented with Spring?

Question

We use Spring to implement REST controller, for example:

@Controller
@RequestMapping("/myservice") 
public class MyController {
    @RequestMapping(value = "foo", method = RequestMethod.GET)
    public @ResponseBody string foo() {...}
}

I can call this service using spring RestTemplate, and it works fine, but I would prefer to invoke it using a proxy, instead of typeless invocation using string url:

// client code:
MyController proxy = getProxy("baseUrl", MyController.class);
String results = proxy.foo();

So the input to proxy generation is java interface with annotations describing REST details. I read this article and it looks like all types of remote calls do have proxies, and all I need for REST is something like RestProxyFactoryBean, that would take my REST java interface and return type-safe proxy that uses RestTemplate as implementation.

The closest solution I found is JBoss RESTEasy.

But it seems to use different set of annotations, so I am not sure it will work with annotations I already have: @Controller, @RequestMapping. Are there other options, or RESTEasy is the only one? Note, I am spring newbie so some obvious spring things are pretty new to me.

Thank you.
Dima

Answer 1

You can try Feign by Netflix, a lightweight proxy-based REST client. It works declaratively through annotations, and it's used by Spring Cloud projects to interact with Netflix Eureka.

Answer 2

One of the reasons the REST paradigm was invented was because expirience with other remoting technologies (RMI, CORBA, SOAP) shows us that often, the proxy-based approach creates more problems than it solves.

Theoretically, a proxy makes the fact that a function call is remote transparent to its users, so they can use the function exactly the same way as if it were a local function call.

In practice however this promise cannot be fulfilled, because remote function calls simply have other properties than local calls. Network outages, congestion, timeouts, load problems to name just a few. If you choose to ignore all these things that can go wrong with remote calls, your code probably won't be very stable.

TL;DR: You probably shouldn't work with a proxy, it's not state of the art any more. Just use RestTemplate.