spring-mvc - 在 Spring MVC 的 Aspect 中未注入(inject) Autowiring 的依赖项

Question

我无法 @Autowire Aspect 中的服务层实例。在方面引用 @Autowired bean 为 NULL 并抛出 NullPointerException .任何帮助都感激不尽。我想，我搞砸了配置。

以下是我的servlet-context.xml :

<!-- Activates various annotations to be detected in bean classes -->
<context:annotation-config />
<context:spring-configured />       

<!-- Scans the classpath of this application for @Components to deploy as beans -->
<context:component-scan base-package="xx.yy" />

<!--  an @AspectJ aspect will be interpreted as an aspect by Spring AOP and beans in the context will be advised accordingly -->
<aop:aspectj-autoproxy />

<beans:bean id="loggingAspect" class="xx.yy.aop.aspects.LoggingAspect" />
<beans:bean id="authenticationAspect" class="xx.yy.aop.aspects.AuthenticationAspect" />

<!-- Enables the Spring MVC @Controller programming model -->
<annotation-driven />

以下是我的方面:

@Configurable
@Component
@Aspect
public class AuthenticationAspect {
private static final Logger logger = LoggerFactory.getLogger(AuthenticationAspect.class);

@Autowired
private LoginService loginService;

    //.... 
}

这是我使用 @Authentication 的 Controller 上面定义的注释:

@Controller
@RequestMapping("/user")
public class UsersController {

@Autowired
private UserService userService;

@Authenticate
@RequestMapping(value="/{userId}/profile", method=RequestMethod.GET)    
public String displayUser(WebRequest webRequest, @PathVariable("userId") String userId, Model model) {
    User user = userService.findUser(Long.valueOf(userId));  
    model.addAttribute("user", user);
    model.addAttribute("AccordionMenuTab","5");
    model.addAttribute("selectedLink","profile");
    return "profile";
}

我收到以下异常:

Oct 8, 2011 3:12:48 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet appServlet threw exception
java.lang.NullPointerException
    at xx.yy.controller.UsersController.displayUser_aroundBody1$advice(UsersController.java:28)
    at xx.yy.controller.UsersController.displayUser(UsersController.java:1)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426)
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Thread.java:662)

Answer 1

见 this piece of the documentation :

7.8.3 Configuring AspectJ aspects using Spring IoC

When using AspectJ aspects with Spring applications, it is natural to both want and expect to be able to configure such aspects using Spring. The AspectJ runtime itself is responsible for aspect creation, and the means of configuring the AspectJ created aspects via Spring depends on the AspectJ instantiation model (the 'per-xxx' clause) used by the aspect.

The majority of AspectJ aspects are singleton aspects. Configuration of these aspects is very easy: simply create a bean definition referencing the aspect type as normal, and include the bean attribute 'factory-method="aspectOf"'. This ensures that Spring obtains the aspect instance by asking AspectJ for it rather than trying to create an instance itself. For example:

<bean id="profiler" class="com.xyz.profiler.Profiler"
      factory-method="aspectOf" />