Class ActionFileUploadInterceptor

All Implemented Interfaces:
Serializable, ConditionalInterceptor, Interceptor

public class ActionFileUploadInterceptor extends AbstractFileUploadInterceptor

Interceptor that is based off of MultiPartRequestWrapper, which is automatically applied for any request that includes a file when the support for multi-part request is enabled, see Disabling file upload.

You can get access to these files by implementing UploadedFilesAware interface. The interceptor will then call UploadedFilesAware.withUploadedFiles(List) when there are files which were accepted during the upload process.

This interceptor will add several field errors, assuming that the action implements ValidationAware. These error messages are based on several i18n values stored in struts-messages.properties, a default i18n file processed for all i18n requests. You can override the text of these messages by providing text for the following keys:

  • struts.messages.error.uploading - a general error that occurs when the file could not be uploaded
  • struts.messages.error.file.too.large - occurs when the uploaded file is too large
  • struts.messages.error.content.type.not.allowed - occurs when the uploaded file does not match the expected content types specified
  • struts.messages.error.file.extension.not.allowed - occurs when the uploaded file does not match the expected file extensions specified

Interceptor parameters:

  • maximumSize (optional) - the maximum size (in bytes) that the interceptor will allow a file reference to be set on the action. Note, this is not related to the various properties found in struts.properties. Default to approximately 2MB.
  • allowedTypes (optional) - a comma separated list of content types (ie: text/html) that the interceptor will allow a file reference to be set on the action. If none is specified allow all types to be uploaded.
  • allowedExtensions (optional) - a comma separated list of file extensions (ie: .html) that the interceptor will allow a file reference to be set on the action. If none is specified allow all extensions to be uploaded.

Example code:

 <action name="doUpload" class="com.example.UploadAction">
     <interceptor-ref name="actionFileUpload"/>
     <interceptor-ref name="basicStack"/>
     <result name="success">good_result.jsp</result>
 </action>
 

You must set the encoding to multipart/form-data in the form where the user selects the file to upload.

   <s:form action="doUpload" method="post" enctype="multipart/form-data">
       <s:file name="upload" label="File"/>
       <s:submit/>
   </s:form>
 

And then in your action code you'll have access to the File object if you provide setters according to the naming convention documented in the start.

  package com.example;

  import java.io.File;
  import org.apache.struts2.ActionSupport;
  import org.apache.struts2.action.UploadedFilesAware;

  public UploadAction extends ActionSupport implements UploadedFilesAware {
    private UploadedFile uploadedFile;
    private String contentType;
    private String fileName;
    private String originalName;

    @Override
    public void withUploadedFiles(List uploadedFiles) {
        if (!uploadedFiles.isEmpty() > 0) {
            this.uploadedFile = uploadedFiles.get(0);
            this.fileName = uploadedFile.getName();
            this.contentType = uploadedFile.getContentType();
            this.originalName = uploadedFile.getOriginalName();
        }
    }

    public String execute() {
       //...
       return SUCCESS;
    }
  }
 
See Also: