為了使用WebWork,我們只需要在web.xml配置FilterDispatcher一個過濾器即可,閱讀一下FilterDispatcher的JavaDoc和源碼,我們可以看到它調用了:
finally
{
ActionContextCleanUp.cleanUp(req);
}
在ActionContextCleanUp中,有這樣的代碼:
req.setAttribute(CLEANUP_PRESENT, Boolean.TRUE);
如果FilterDispatcher檢測到這個屬性,就不會清除ActionContext中的內容了,而由ActionContextCleanUp后續的代碼來清除,保證了一系列的Filter訪問正確的ActionContext.
文檔中提到,如果用到SiteMesh的Filter或者其他類似Filter,那么設置順序是:
ActionContextCleanUp filter
SiteMesh filter
FilterDispatcher
所以最后我們的web.xml應該類似這樣:
<filter>
<filter-name>ActionContextCleanUp</filter-name>
<filter-class>com.opensymphony.webwork.dispatcher.ActionContextCleanUp</filter-class>
</filter>
<filter>
<filter-name>sitemesh</filter-name>
<filter-class>com.opensymphony.webwork.sitemesh.FreeMarkerPageFilter</filter-class>
</filter>
<filter>
<filter-name>webwork</filter-name>
<filter-class>com.opensymphony.webwork.dispatcher.FilterDispatcher</filter-class>
</filter>
<filter-mapping>
<filter-name>ActionContextCleanUp</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>sitemesh</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>webwork</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>