title: Handling several implementations of one Spring bean/interface in one class field
body: <p>Similar to this <a href="https://stackoverflow.com/questions/11777079/handling-several-implementations-of-one-spring-bean-interface">question</a>, but I have this situation. Suppose I have one <code>AccountService</code> interface and two implementations: <code>DefaultAccountServiceImpl</code> and <code>SpecializedAccountServiceImpl</code>, (the classes just like in the previous <a href="https://stackoverflow.com/questions/11777079/handling-several-implementations-of-one-spring-bean-interface">question</a>). The implementation is in one class, but has different bean implementation for different method. Say:</p>
  
  <pre><code>@RestController
  @RequestMapping("/account")
  public class AccountManagerRestController {
  
      @Autowired
      private AccountService service;
  
      @RequestMapping(value = "/register", method = RequestMethod.POST)
      HttpEntity&lt;?&gt; registerAccount(@RequestBody AccountRegisterRequestBody input) {
          // here the `service` is DefaultAccountServiceImpl
          ...
      }
  
  
      @RequestMapping(value = "/register/specialized", method = RequestMethod.POST)
      HttpEntity&lt;?&gt; registerSpecializedAccount(@RequestBody AccountRegisterRequestBody input) {
          // here the `service` is SpecializedAccountServiceImpl
          ...
      }
  }
  </code></pre>