在Spring中正确配置mvc：interceptor

Question

我有点问题。我需要在此拦截器中调用每个请求的postHandle方法：

public class DiMenuInterceptor extends HandlerInterceptorAdapter {

   @Autowired
   private IDiCategoryService categoryService;


   @Override
   public void postHandle(HttpServletRequest request,
        HttpServletResponse response, Object handler,
        ModelAndView modelAndView) throws Exception {

       modelAndView.addObject("category", categoryService.getCategoryInTree());
   }
}

所以我将这一行放入servlet配置中，一切正常。

<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" p:interceptors-ref="menuInterceptor" />

<bean id="menuInterceptor" class="cz.cosi.DiMenuInterceptor" />

但是现在我必须更改配置和使用 <mvc:interceptors>

通过这种配置，我在postHandle方法中的modelAndView上得到了一系列空指针异常，因为每个请求多次调用postHandle方法。

 <mvc:interceptors>
    <bean class="cz.cosi.DiMenuInterceptor" />
 </mvc:interceptors>

使用此配置，它可以工作，但仅适用于请求serverAdress /任何东西。对于请求serverAdress /任何东西/东西不调用postHandle。

<mvc:interceptors>
   <mvc:interceptor>
     <mvc:mapping path="/*" />
     <bean class="cz.cosi.DiMenuInterceptor" />
   </mvc:interceptor>
</mvc:interceptors>

servlet配置的一部分

<mvc:annotation-driven />

<bean id="messageSource"
    class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
    <property name="basename" value="classpath:messages" />
    <property name="defaultEncoding" value="UTF-8" />       

</bean>

<mvc:resources mapping="/css/**" location="/css/" />
<mvc:resources mapping="/images/**" location="/images/" />
<mvc:resources mapping="/js/**" location="/js/" />

<mvc:interceptors>
    <bean class="cz.cosi.DiMenuInterceptor" />
</mvc:interceptors>

<tx:jta-transaction-manager />

<tx:annotation-driven />

<bean id="transactionManager"
    class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

看来，问题可能与资源有关，因为没有正确加载图像，样式和javascript例外。没有mvc：resources可以正常工作，但这不是解决方案。

我的问题是，如何正确配置DiMenuInterceptor <mvc:interceptors>。非常感谢你的建议。

stack:

2019-04-14 09:56:02,487 [http-8080-3] DEBUG (FilterChainProxy.java:195) ? Converted URL to lowercase, from: '/images/core/users/super_admin.png'; to: '/images/core/users/super_admin.png'
2019-04-14 09:56:02,533 [http-8080-3] DEBUG (FilterChainProxy.java:202) ? Candidate is: '/images/core/users/super_admin.png'; pattern is /images/**; matched=true
2019-04-14 09:56:02,533 [http-8080-3] DEBUG (FilterChainProxy.java:158) ? /images/core/users/super_admin.png has an empty filter list
14.4.2011 9:56:02 org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet spring threw exception
java.lang.NullPointerException
    at cz.cosi.DiMenuInterceptor.postHandle(DiMenuInterceptor.java:41)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:801)
    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.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:163)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    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:595)

也许我找到了解决方案，但这绝对不是最好的。目前看来，这是可行的。

<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/*" />
        <bean class="cz.cosi.DiMenuInterceptor" />
    </mvc:interceptor>
    <mvc:interceptor>
         <mvc:mapping path="/search/**" />
        <bean class="cz.cosi.DiMenuInterceptor" />
    </mvc:interceptor>

    <mvc:interceptor>
         <mvc:mapping path="/context/**" />
        <bean class="cz.cosi.DiMenuInterceptor" />
    </mvc:interceptor>
    <mvc:interceptor>
          <mvc:mapping path="/member/**" />
        <bean class="cz.cosi.DiMenuInterceptor" />
    </mvc:interceptor>

</mvc:interceptors>

Answer 1

你需要指定你的路径包括子路径：/**"不是/*。

<mvc:interceptors>
   <mvc:interceptor>
     <mvc:mapping path="/**" />
     <bean class="cz.cosi.DiMenuInterceptor" />
   </mvc:interceptor>
</mvc:interceptors>