How do we upload files

You can obtain the MultipartRequestWrapper from the ServletActionContext or by utilizing the fileUpload interceptor. The fileUpload interceptor is preferred.

Ask the ServletActionContext

MultipartRequestWrapper multipartRequest = ((MultipartRequestWrapper)ServletActionContext.getRequest())

The MultipartRequestWrapper provideds access methods such as getFiles, getFile, getContentType, hasErrors, getErrors, and so forth, so that you can process the file uploaded.

Utilize the fileUpload Interceptor

_Preferred_

• Ensure that {{fileUpload }} Interceptor is included in the Action's stack.
  • The default stack already includes {{fileUpload }}.
• Ensure that the HTML form sets the enctype and specifies on or more file type inputs.

<form name="myForm" enctype="multipart/form-data">
     <input type="file" name="myDoc" value="Browse ..." />
     <input type="submit" />
  </form>

• Ensure that the Action provides one or more fileUpload mutator methods, with names that correspond to name of the file type input.

public void setMyDoc(File myDoc)
public void setMyDocContentType(String contentType)
public void setMyDocFileName(String filename)

• The Action may also provide the corresponding accessor methods.

public File getMyDoc()
public String getMyDocContentType()
public String getMyDocFileName()

Handling multiple files

When multiple files are uploaded by a form, the files are represented by an array.

Given:

<form name="myForm" enctype="multipart/form-data">
      <input type="file" name="myDoc" value="Browse File A ..." />
      <input type="file" name="myDoc" value="Browse File B ..." />
      <input type="file" name="myDoc" value="Browse File C ..." />
      <input type="submit" />
   </form>

The Action class can define file handling methods that accept an array.

public void setMyDoc(File[] myDocs)
public void setMyDocContentType(String[] contentTypes)
public void setMyDocFileName(String[] fileNames)

The uploaded files can be handled by iterating through the appropriate array.

Extra Information

@see struts.properties
@see org.apache.struts2.dispatcher.FilterDispatcher#doFilter(SerlvetRequest, ServletRepsonse, FilterChain)
@see org.apache.struts2.dispatcher.DispatcherUtil#wrapRequest(HttpServletRequest, SerlvetContext)
@see org.apache.struts2.dispatcher.multipart.MultipartRequestWrapper
@see org.apache.struts2.interceptor.FileUploadInterceptor