如何在filter中注入bean

web.xml配置一个   
          <filter>   
                  <filter-name>DelegatingFilterProxy</filter-name>   
                  <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>   
                  <init-param>   
                          <param-name>targetBeanName</param-name>   
                          <param-value>myFilter</param-value>   
                  </init-param>   
                  <init-param>   
                          <param-name>targetFilterLifecycle</param-name>   
                          <param-value>true</param-value>   
                  </init-param>   
          </filter>   
    
          <filter-mapping>   
                  <filter-name>DelegatingFilterProxy</filter-name>   
                  <url-pattern>/*</url-pattern>   
          </filter-mapping>   
    
  applicationcontext.xml配置:     
  <bean   id="myFilter"   class="skycncomp.util.CookieFilter">     
  <property   name="userDao">     
  <ref   bean="userDao"/>     
  </property>     
  </bean>     
  <bean   id="userDao"   class="skycncomp.UserDAO">     
  </bean>