在配置web工程中的web.xml文件时,filter可以过滤servlet,那对同一个servlet配置多个filter时,执行顺序是怎样的呢?看如下配置:
<filter> <filter-name>CheckLoginFilter</filter-name> <filter-class>web.CheckLoginFilter</filter-class> </filter> <filter-mapping> <filter-name>CheckLoginFilter</filter-name> <servlet-name>mvc-dispatcher</servlet-name> </filter-mapping> <filter> <filter-name>Set Character Encoding</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>Set Character Encoding</filter-name> <servlet-name>mvc-dispatcher</servlet-name> </filter-mapping> <filter> <filter-name>httpPutFormFilter</filter-name> <filter-class>org.springframework.web.filter.HttpPutFormContentFilter</filter-class> </filter> <filter-mapping> <filter-name>httpPutFormFilter</filter-name> <servlet-name>mvc-dispatcher</servlet-name> </filter-mapping> <servlet> <servlet-name>mvc-dispatcher</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:mvc-dispatcher-servlet.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>mvc-dispatcher</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping>
filter的执行顺序是根据filter-mapping配置的先后执行的。按照上面的配置,第一个filter执行是CheckLoginFilter。那么servlet什么时候执行呢?
那要看一下webx中配置的执行顺序:listener->filter->servlet。
所以上面的配置执行顺序是:CheckLoginFilter->Set Character Encoding->httpPutFormFilter->mvc-dispatcher。