@Autowired
    public void setUserService(UserService userService) {
        this.userService = userService;
    }
A Spring MVC interceptor that adds the currentUser into the request as a request attribute
before the JSP is rendered.  This operation is assumed to be fast because the User should be
cached in the Hibernate second-level cache.
samples/spring-hibernate/src/main/java/org/apache/shiro/samples/sprhib/web/CurrentUserInterceptor.java