Class FileUploadInterceptor

  extended by com.opensymphony.xwork2.interceptor.AbstractInterceptor
      extended by org.apache.struts2.interceptor.FileUploadInterceptor
All Implemented Interfaces:
Interceptor, Serializable

public class FileUploadInterceptor
extends AbstractInterceptor

Interceptor that is based off of MultiPartRequestWrapper, which is automatically applied for any request that includes a file. It adds the following parameters, where [File Name] is the name given to the file uploaded by the HTML form:

You can get access to these files by merely providing setters in your action that correspond to any of the three patterns above, such as setDocument(File document), setDocumentContentType(String contentType), etc.
See the example code section.

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

Interceptor parameters:

Extending the interceptor:

You can extend this interceptor and override the acceptFile(, java.lang.String, java.lang.String, com.opensymphony.xwork2.ValidationAware, java.util.Locale) method to provide more control over which files are supported and which are not.

Example code:

 <action name="doUpload" class="com.examples.UploadAction">
     <interceptor-ref name="fileUpload"/>
     <interceptor-ref name="basicStack"/>
     <result name="success">good_result.ftl</result>
And then you need to set encoding multipart/form-data in the form where the user selects the file to upload.
   <a:form action="doUpload" method="post" enctype="multipart/form-data">
       <a:file name="upload" label="File"/>
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.
    public com.examples.UploadAction implemements Action {
       private File file;
       private String contentType;
       private String filename;

       public void setUpload(File file) {
          this.file = file;

       public void setUploadContentType(String contentType) {
          this.contentType = contentType;

       public void setUploadFileName(String filename) {
          this.filename = filename;


See Also:
Serialized Form

Field Summary
protected  String allowedTypes
protected  Set allowedTypesSet
private static String DEFAULT_DELIMITER
private static String DEFAULT_MESSAGE
protected static Log log
protected  Long maximumSize
private static long serialVersionUID
Constructor Summary
Method Summary
protected  boolean acceptFile(File file, String contentType, String inputName, ValidationAware validation, Locale locale)
          Override for added functionality.
private static boolean containsItem(Collection itemCollection, String key)
private static Set getDelimitedValues(String delimitedString)
private  String getTextMessage(String messageKey, Object[] args, Locale locale)
 String intercept(ActionInvocation invocation)
          Override to handle interception
private static boolean isNonEmpty(Object[] objArray)
 void setAllowedTypes(String allowedTypes)
          Sets the allowed mimetypes
 void setMaximumSize(Long maximumSize)
          Sets the maximum size of an uploaded file
Methods inherited from class com.opensymphony.xwork2.interceptor.AbstractInterceptor
destroy, init
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail


private static final long serialVersionUID
See Also:
Constant Field Values


protected static final Log log


private static final String DEFAULT_DELIMITER
See Also:
Constant Field Values


private static final String DEFAULT_MESSAGE
See Also:
Constant Field Values


protected Long maximumSize


protected String allowedTypes


protected Set allowedTypesSet
Constructor Detail


public FileUploadInterceptor()
Method Detail


public void setAllowedTypes(String allowedTypes)
Sets the allowed mimetypes

allowedTypes - A comma-delimited list of types


public void setMaximumSize(Long maximumSize)
Sets the maximum size of an uploaded file

maximumSize - The maximum size in bytes


public String intercept(ActionInvocation invocation)
                 throws Exception
Description copied from class: AbstractInterceptor
Override to handle interception

Specified by:
intercept in interface Interceptor
Specified by:
intercept in class AbstractInterceptor
the return code, either returned from ActionInvocation.invoke(), or from the interceptor itself.
Exception - any system-level error, as defined in Action.execute().


protected boolean acceptFile(File file,
                             String contentType,
                             String inputName,
                             ValidationAware validation,
                             Locale locale)
Override for added functionality. Checks if the proposed file is acceptable based on contentType and size.

file - - proposed upload file.
contentType - - contentType of the file.
inputName - - inputName of the file.
validation - - Non-null ValidationAware if the action implements ValidationAware, allowing for better logging.
locale -
true if the proposed file is acceptable by contentType and size.


private static boolean containsItem(Collection itemCollection,
                                    String key)
itemCollection - - Collection of string items (all lowercase).
key - - Key to search for.
true if itemCollection contains the key, false otherwise.


private static Set getDelimitedValues(String delimitedString)


private static boolean isNonEmpty(Object[] objArray)


private String getTextMessage(String messageKey,
                              Object[] args,
                              Locale locale)

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