问题描述
我有一个带有自定义过滤器的 Spring Boot 应用程序:
import javax.servlet.Filter
public class MyFilter implements Filter{
@Override
public void doFilter(ServletRequest request,ServletResponse response,FilterChain chain) {
System.out.println("MyFilter");
}
}
应用程序中的某些控制器在其方法上具有自定义注释。 所有自定义注解都实现了 myAnnotation 接口。
@GetMapping("/")
@MyCustomAnnotation
@AnotherCustomAnnotation
public ResponseEntity<String> get(){
addSomeMetric();
return new ResponseEntity<>("Hello world",HttpStatus.OK);
}
如何从 doFilter 代码中获取在 URI 端点上定义的所有注释的列表?
解决方法
Spring AOP 可用于根据请求/用户决定是否需要执行控制器方法。
以下代码是实现相同的一种方式。
@Aspect
@Component
public class AnnotationFilterAspect {
@Pointcut("execution(public * package.controller..*(..))")
public void allControllerMethods() {
}
@Around("allControllerMethods()")
public Object checkAccess(ProceedingJoinPoint pjp) {
Object retObject = null;
Method method = getMethod(pjp);
for(Annotation anno : method.getAnnotations()){
System.out.println(anno.annotationType());
// Annotation details
}
// Logged in user details
Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
String currentUserName = authentication.getName();
//or
//Get the HttpServletRequest currently bound to the thread.
HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes())
.getRequest();
// Logic to proceed to the controller method based on the logged in user or request can be done here.
try {
retObject = pjp.proceed();
} catch (Throwable e) {
// Handle the exception
}
return retObject;
}
//Refer : https://stackoverflow.com/q/5714411/4214241
private Method getMethod(ProceedingJoinPoint pjp) {
MethodSignature signature = (MethodSignature) pjp.getSignature();
Method method = signature.getMethod();
if (method.getDeclaringClass().isInterface()) {
try {
method= pjp.getTarget().getClass().getDeclaredMethod(pjp.getSignature().getName(),method.getParameterTypes());
} catch (final SecurityException exception) {
//...
} catch (final NoSuchMethodException exception) {
//...
}
}
return method;
}
}
另请注意,注释 RetentionPolicy 必须是 RUNTIME ,此代码才能工作。
,我最终使用了 HandlerInterceptor 而不是过滤器。
由于我只针对 Web 请求,因此它似乎是比 AOP 更好、更简单的解决方案。
@Override
public boolean preHandle(@NonNull HttpServletRequest request,@NonNull HttpServletResponse response,@NonNull Object handler) {
MyAnnotation myAnnotation = getMyAnnotation(handler);
}
private MyAnnotation getMyAnnotation(Object handler) {
HandlerMethod handlerMethod = (HandlerMethod) handler;
Method method = handlerMethod.getMethod();
return method.getAnnotation(MyAnnotation.class);
}