struts2配置文件如下：

    list
    /main
    ${blogId}
    true
   
运行时后台出现了如下错误，但是前台运行结果正常显示：
2011-04-04 19:37:44,734 ERROR [com.opensymphony.xwork2.ObjectFactory] - Unable to set parameter [blogId] in result of type [org.apache.struts2.dispatcher.ServletActionRedirectResult]
Caught OgnlException while setting property 'blogId' on type 'org.apache.struts2.dispatcher.ServletActionRedirectResult'. - Class: ognl.ObjectPropertyAccessor
File: ObjectPropertyAccessor.java
Method: setProperty
Line: 132 - ognl/ObjectPropertyAccessor.java:132:-1
 at com.opensymphony.xwork2.ognl.OgnlUtil.internalSetProperty(OgnlUtil.java:392)
 at com.opensymphony.xwork2.ognl.OgnlUtil.setProperty(OgnlUtil.java:143)
 at com.opensymphony.xwork2.ognl.OgnlReflectionProvider.setProperty(OgnlReflectionProvider.java:91)……
查看了一下两个action的blogId的get/set方法都设置了，但是还是出现了这个问题
把ognl表达式去掉直接传常量，同样出现这样的问题（所以我感觉不是ognl表达式的问题），到网上查了查，结果是：
You can ignore the exception(yeah I know it smells to the moon), or
increase the log level for the ObjectFactory, it is a bug in Struts
which was re-introduced in 2.1.6 (/facepalm)
呵呵~