org.apache.struts2.interceptor
Class FileUploadInterceptor

java.lang.Object
  com.opensymphony.xwork2.interceptor.AbstractInterceptor
      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:

• [File Name] : File - the actual File
• [File Name]ContentType : String - the content type of the file
• [File Name]FileName : String - the actual name of the file uploaded (not the HTML name)

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 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.

Extending the interceptor:

You can extend this interceptor and override the acceptFile method to provide more control over which files are supported and which are not.

Example code:

 
 <action name="doUpload" class="com.example.UploadAction">
     <interceptor-ref name="fileUpload"/>
     <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 com.opensymphony.xwork2.ActionSupport;
 

    public UploadAction extends ActionSupport {
       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;
       }
 

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

See Also:

Serialized Form

Field Summary

protected Set<String>	allowedExtensionsSet
protected Set<String>	allowedTypesSet
protected static Logger	LOG
protected Long	maximumSize
protected boolean	useActionMessageBundle

Constructor Summary

FileUploadInterceptor()

Method Summary

protected boolean	acceptFile(Object action, File file, String filename, String contentType, String inputName, ValidationAware validation, Locale locale) Override for added functionality.
String	intercept(ActionInvocation invocation)
void	setAllowedExtensions(String allowedExtensions) Sets the allowed extensions
void	setAllowedTypes(String allowedTypes) Sets the allowed mimetypes
void	setMatcher(PatternMatcher matcher)
void	setMaximumSize(Long maximumSize) Sets the maximum size of an uploaded file
void	setUseActionMessageBundle(String value)

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

LOG

protected static final Logger LOG

useActionMessageBundle

protected boolean useActionMessageBundle

maximumSize

protected Long maximumSize

allowedTypesSet

protected Set<String> allowedTypesSet

allowedExtensionsSet

protected Set<String> allowedExtensionsSet

Constructor Detail

FileUploadInterceptor

public FileUploadInterceptor()

Method Detail

setMatcher

public void setMatcher(PatternMatcher matcher)

setUseActionMessageBundle

public void setUseActionMessageBundle(String value)

setAllowedExtensions

public void setAllowedExtensions(String allowedExtensions)

Sets the allowed extensions

Parameters:

allowedExtensions - A comma-delimited list of extensions

setAllowedTypes

public void setAllowedTypes(String allowedTypes)

Sets the allowed mimetypes

Parameters:

allowedTypes - A comma-delimited list of types

setMaximumSize

public void setMaximumSize(Long maximumSize)

Sets the maximum size of an uploaded file

Parameters:

maximumSize - The maximum size in bytes

intercept

public String intercept(ActionInvocation invocation)
                 throws Exception

Specified by:

intercept in interface Interceptor

Specified by:

intercept in class AbstractInterceptor

Throws:

Exception

acceptFile

protected boolean acceptFile(Object action,
                             File file,
                             String filename,
                             String contentType,
                             String inputName,
                             ValidationAware validation,
                             Locale locale)

Override for added functionality. Checks if the proposed file is acceptable based on contentType and size.

Parameters:

action - - uploading action for message retrieval.

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 -

Returns:

true if the proposed file is acceptable by contentType and size.