在客户端上使用Spring RESTful API的简单方法？

Question

我想知道是否有可能为Android应用程序创建API .jar，以便我能够像这样使用它：

HelloWorldExampleAPI api;

HelloWorld helloWorld = api.getHelloWorldConnector();

helloWorld.displayMessage("How are you?");

而不是像这样实施AsyncTasks：

class RequestTask extends AsyncTask<String, String, String> {

    @Override
    protected String doInBackground(String... uri) {

        String msg = "";
        for(String m : uri) { msg += m; }

        String url = "http://192.168.42.229:8080/HelloWorldExample/helloWorld/displayMessage/" + msg;

        RestTemplate restTemplate = new RestTemplate();

        restTemplate.getMessageConverters().add(new StringHttpMessageConverter());

        // Make the HTTP GET request, marshaling the response to a String
        return restTemplate.getForObject(url, String.class, "Android");
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
    }
}

从这个简单的servlet示例：

@Controller
@RequestMapping("/helloWorld")
public class HelloWorldController {

    @RequestMapping(value = "/hello", method = RequestMethod.GET)
    public String hello(ModelMap model) {
        System.out.println("/hello");
        model.addAttribute("msg", "JCG Hello World!");
        return "helloWorld";
    }

    @RequestMapping(value = "/displayMessage/{msg}", method = RequestMethod.GET)
    public String displayMessage(@PathVariable String msg, ModelMap model) {
        System.out.println("/displayMessage/{msg} : " + msg);
        model.addAttribute("msg", msg);
        return "helloWorld";
    }
}