ssh 框架 + springsecurity 下使用 struts2 fileupload 的冲突问题

struts2文件上传功能使用，简单易操作，网上资料很多，此处略。

当项目中使用springsecurity，struts2的文件上传会产生问题，File对象总是NULL，无法获得form表单中file字段的二进制文件流，经过排出检查，发现是struts2的fileUpload拦截器与springsecurity的拦截器springSecurityFilterChain冲突造成，也就是两者filter-mapping的位置放置错误造成的。正确的放置顺序应该是如下：

    <filter-mapping>
        <filter-name>hibernateOpenSessionInViewFilter</filter-name>
        <url-pattern>/j_spring_security_check</url-pattern>
    </filter-mapping>
    
    <filter-mapping>
        <filter-name>springSecurityFilterChain</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <filter-mapping>  
        <filter-name>struts-prepare</filter-name>  
        <url-pattern>*.action</url-pattern>  
    </filter-mapping>
    
    <filter-mapping>
        <filter-name>hibernateOpenSessionInViewFilter</filter-name>
        <url-pattern>*.action</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
    </filter-mapping>
    

      
    <filter-mapping>  
        <filter-name>sitemesh</filter-name>  
        <url-pattern>/*</url-pattern>  
        <dispatcher>REQUEST</dispatcher>  
        <dispatcher>FORWARD</dispatcher>  
        <dispatcher>INCLUDE</dispatcher>  
    </filter-mapping> 
      
    <filter-mapping>  
        <filter-name>struts-execute</filter-name>  
        <url-pattern>*.action</url-pattern>  
    </filter-mapping> 

springSecurityFilterChain应该在struts-prepare与struts-execute外。