I want to create Spring aspect which would set method parameter, annotated by custom annotation, to an instance of a particular class identified by an id from URI template. Path variable name is parameter of the annotation. Very similar to what Spring @PathVariable does.
So that controller method would look like:
@RestController
@RequestMapping("/testController")
public class TestController {
@RequestMapping(value = "/order/{orderId}/delete", method = RequestMethod.GET)
public ResponseEntity<?> doSomething(
@GetOrder("orderId") Order order) {
// do something with order
}
}
Instead of classic:
@RestController
@RequestMapping("/testController")
public class TestController {
@RequestMapping(value = "/order/{orderId}/delete", method = RequestMethod.GET)
public ResponseEntity<?> doSomething(
@PathVariable("orderId") Long orderId) {
Order order = orderRepository.findById(orderId);
// do something with order
}
}
Annotation source:
// Annotation
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface GetOrder{
String value() default "";
}
Aspect source:
// Aspect controlled by the annotation
@Aspect
@Component
public class GetOrderAspect {
@Around( // Assume the setOrder method is called around controller method )
public Object setOrder(ProceedingJoinPoint jp) throws Throwable{
MethodSignature signature = (MethodSignature) jp.getSignature();
@SuppressWarnings("rawtypes")
Class[] types = signature.getParameterTypes();
Method method = signature.getMethod();
Annotation[][] annotations = method.getParameterAnnotations();
Object[] values = jp.getArgs();
for (int parameter = 0; parameter < types.length; parameter++) {
Annotation[] parameterAnnotations = annotations[parameter];
if (parameterAnnotations == null) continue;
for (Annotation annotation: parameterAnnotations) {
// Annotation is instance of @GetOrder
if (annotation instanceof GetOrder) {
String pathVariable = (GetOrder)annotation.value();
// How to read actual path variable value from URI template?
// In this example case {orderId} from /testController/order/{orderId}/delete
HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder
.currentRequestAttributes()).getRequest();
????? // Now what?
}
} // for each annotation
} // for each parameter
return jp.proceed();
}
}
UPDATE 04/Apr/2017:
Answer given by Mike Wojtyna answers the question -> thus it is accepted.
Answer given by OrangeDog solves the problem form different perspective with existing Spring tools without risking implementation issue with new aspect.
Thank you!
If you already have access to HttpServletRequest, you can use HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE spring template to select map of all attributes in the request. You can use it like that:
request.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE)
The result is a Map instance (unfortunately you need to cast to it), so you can iterate over it and get all the parameters you need.