Struts2 验证信息的迭代输出

<s:if test="hasFieldErrors()">  
         <s:iterator value="fieldErrors">  
             <s:iterator value="value" status="statu">  
                //field的错误消息是List 因此还需要迭代一次       
                 <s:set name="index" value="#statu.index"/>  
                 <s:set name="msg" value="#msg==null?'':#msg+  
                 value.get(#request.index).toString()+'\\\n'"/>//关键代码  
              </s:iterator>  
         </s:iterator>  
</s:if>
<s:if test="hasActionErrors()">  
         <s:iterator value="actionErrors">  
                <script   language="JavaScript">  
                 alert("<s:property escape="false"/>")  
                </script>  
             </s:iterator>  
</s:if>
<s:if test="hasActionMessages()">  
         <s:iterator value="actionMessages">  
             <script language="JavaScript">  
                 alert("<s:property escape="false"/>")  
             </script>  
         </s:iterator>  
</s:if>  
 
         //打印转换好格式的fielderror信息  
<s:if test="#msg.length()>0">  
         <script language="JavaScript">  
             alert("<s:property escape="false" value="#msg"/>")  
         </script>  
</s:if>