Struts2 File Upload is empty

Many friends, like me, get the file null

The properties are certainly true. Why is it.

is because struts2 upload to add intercept,

Such as:

(1) <action name= "file" class= "Fileaction" >
<!--Auto Register action:2010-07-07 14:22:37.281-->
<!--configuring FileUpload interceptors--
<interceptor-ref name= "FileUpload" >
<!--configuration allows file size to be uploaded--
<param name= "MaximumSize" >4000000</param>
</interceptor-ref>
<interceptor-ref name= "Defaultstack" ></interceptor-ref>
<param name= "Save_path" >/fileout</param>
<result name= "FileInfo" type= "JSON" >
file/file.jsp
</result>
</action>

After configuration, the file can be uploaded normally.

(2) must be post and enctype= "Multipart/form-data"

<form action= ". /console/processreleaseaction!uploadfile.action "method=" post "enctype=" Multipart/form-data ">
<input type= "file" value= "Upload" name= "Flowfile"/>
<input type= "Submit" value= "submitted" id= "Submission"/>
</form>

(3) The variable of action is the same as the name of the form, and there is a get and set method, which I will not write in detail.

/**
* @ Property Description: Receive client file information
**/
Private File Flowfile;

/**
* @ Property Description: Receive client file filename
**/
Private String Flowfilefilename;

Private String Flowfilecontenttype;

(4) Filter configuration for STRUTS2

<action name= "Processreleaseaction" class= " Cn.net.sinodata.sinoflow.console.processrelease.action.ProcessReleaseAction ">
<interceptor-ref name= "FileUpload" >
<param name= "MaximumSize" >4000000</param>
</interceptor-ref>
<interceptor-ref name= "Defaultstack" ></interceptor-ref>
<result name= "Success" >/WEB-INF/jsp/console/processrelease/processRelease.jsp</result>
</action>

(5) The STRUTS2 configuration of Web. XML is added (this is a separate file upload filter added on the struts2 base configuration, details Struts2 book introduction)

<filter>
<filter-name>struts-cleanup</filter-name>
<filter-class>
Org.apache.struts2.dispatcher.ActionContextCleanUp
</filter-class>
</filter>

(6) struts.xml add <constant name= "struts.multipart.maxSize" value= "1073741824"/> the complete struts.xml is

<?xml version= "1.0" encoding= "UTF-8"?>
<! DOCTYPE struts Public "-//apache software foundation//dtd struts Configuration 2.0//en" "http://struts.apache.org/dtds/ Struts-2.0.dtd ">
<struts>
<constant name= "Struts.ui.theme" value= "simple"/>
<constant name= "struts.i18n.encoding" value= "GBK"/>
<constant name= "struts.custom.i18n.resources" value= "Globalmessages"/>
<constant name= "struts.multipart.maxSize" value= "1073741824"/>
<!--introduce relevant profiles--
<include file= "Cn/net/sinodata/sinoflow/config/struts/struts-common.xml"/>
<include file= "Cn/net/sinodata/ua/config/struts/user.xml"/>
</struts>

<7> no more, confirm the jar package is OK, please add qq654382144 ...