How to do a @CustomAnnotation annotation that triggers a filter in Spring 3 MVC?

Question

I'd like to do @CustomFilter annotation in Spring 3 mvc like this:

@CustomFilter
@RequestMapping("/{id}")
public Account retrieve(@PathVariable Long id) {
    // ...
}

(Assuming upgrading to Spring 4 is constrained) What I have to do at the moment with Spring 3 looks like this:

public class CustomFilter implements Filter {
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;
        .... 
        chain.doFilter(req, res);
    }
}

My question is: How to do a @CustomAnnotation annotation that triggers a Filter in Spring 3 MVC?

Answer 1

You could pick up a custom annotation using a HandlerInterceptor.

Create your marker annotation:

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface CustomFilter {
}

Create a HandlerInterceptor:

public class CustomFilterHandlerInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws
        Exception {

        if (handler instanceof HandlerMethod) {
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            // Test if the controller-method is annotated with @CustomFilter
            CustomFilter filter = handlerMethod.getMethod().getAnnotation(CustomFilter.class);
            if (filter != null) {
                // ... do the filtering
            }
        }
        return true;
    }
}

Register the interceptor:

<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/**" />
        <bean class="com.example.CustomFilterHandlerInterceptor" />
    </mvc:interceptor>
</mvc:interceptors>