Struts2 Fileupload giving null file in the action class

Question

I am trying to implement the file upload process in my web application using struts2 fileUpload interceptor. below is my code in

index.jsp

<tags:form action="fileUpload" method="post" enctype="multipart/form-data">
   <tags:file name="fileUpload" label="Choose File"/>
   <tags:submit value="Upload"/>     
</tags:form>

struts.xml

<action name="fileUpload" class="com.hibernate.action.FileUploadAction">
    <interceptor-ref name="fileUploadStack"/>
    <interceptor-ref name="fileUpload">
        <param name="maximumSize">1024000</param>
        <param name="allowedTypes">application/pdf</param>
    </interceptor-ref>
    <result name="success">/viewChapters.jsp</result>
</action>

FileUploadAction.java

public class FileUploadAction extends ActionSupport
{
private File fileUpload;
private String contentType;
private String fileName;
private String destPath;
/// setter and getter methods
 public String execute()
{
    destPath="C:\\WebPortal_testing";
    try
    {
        System.out.println("Source File Name:"+fileUpload);
        System.out.println("Destination File Name:"+fileName);

        File destFile= new File(destPath,fileName);
        FileUtils.copyFile(fileUpload, destFile);
    }
    catch(IOException exception)
    {
        exception.printStackTrace();
        return ERROR;
    }
    return SUCCESS;
 }

when I select a pdf file in the index.jsp page and click on upload button it is giving null value to the fileUpload field of the action class.

I am executing the application in debug mode and gave this

System.out.println("Source File Name:"+fileUpload);

to check what it is returning and I am getting null.

score 2 · Accepted Answer · edited May 23 '17 at 11:53

2

1. Interceptor configuration is wrong

FileUploadStack is:

<!-- Sample file upload stack -->
<interceptor-stack name="fileUploadStack">
    <interceptor-ref name="fileUpload"/>
    <interceptor-ref name="basicStack"/>
</interceptor-stack>

then what you're really defining is:

    <interceptor-ref name="fileUpload"/>
    <interceptor-ref name="basicStack"/>
    <interceptor-ref name="fileUpload">
        <param name="maximumSize">1024000</param>
        <param name="allowedTypes">application/pdf</param>
    </interceptor-ref>

Using

two times the fileUpload interceptor
applying your limitations on maximumSize and allowedTypes only to the second.

Just do

<interceptor-ref name="fileUploadStack">
    <param name="fileUpload.maximumSize">1024000</param>
    <param name="fileUpload.allowedTypes">application/pdf</param>
</interceptor-ref>

2. File attributes are wrong

Content type and file name attributes must start with the File attribute name.

In your case:

private File fileUpload;
private String fileUploadContentType;
private String fileUploadFileName;

You can find a full example on this question.

3. You are printing the File instead of the filename

System.out.println("Source File Name:"+fileUpload);

That is the file, not the filename, and btw the filename is passed in the other variable.

Fix this and retry. Also note that is not safe to use <tags: as prefix when the whole world is using <s:. There's no gain in doing that, only complications. Just use <s:.

edited May 23 '17 at 11:53

Community

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answered Nov 13 '15 at 16:38

Andrea Ligios

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Thanks for your response. regarding your 3. You are printing the File instead of the filename I am using this only for testing purpose. I have updated every thing as per your suggestions but no luck. I am still getting the same issue. – Ghost Rider Nov 13 '15 at 16:57
Then check carefully the setters, or post more details because everything now seems fine – Andrea Ligios Nov 13 '15 at 17:24
sorry for the delay. I am still facing the issue. I have put that part of implementation on hold and working on other parts of the application where I am facing few other issues. I will post those doubts in a while please comment on them when free. my sincere thanks for your help – Ghost Rider Nov 17 '15 at 12:04
Ok, can you edit your question by applying the latest code tried (the one with the modifies suggested in the answer) ? So I can check what is going south – Andrea Ligios Nov 17 '15 at 13:42
@AndreaLigios The `struts2` `fileupload` interceptor is not checking content type whether the file content is image or not. While uploading text file as image (I changed extension of file from `txt` to `png`) its accepting means file upload has been done. I think its just checking extension. I also set `allowedTypes` as `image/bmp,image/png,image/gif,image/jpeg,image/jpg`. Correct me if I did wrong. I'm using `struts2.3.32` version. If I upload actual image its uploading, so its correct. – SatyaTNV Mar 17 '17 at 07:13
@Satya it's a browser fault. The browser detects the contentType to pass mainly basing on the extension; hence it will often send a wrong contentType if the extension is not correct. You can check it by examining the contentType in the request sent. Read more: http://stackoverflow.com/a/42803060/1654265 – Andrea Ligios Mar 17 '17 at 09:04

Struts2 Fileupload giving null file in the action class

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