Uploading a file with Struts 2

Uploading a file with Struts 2 is really simple with the help of the FileUploadInterceptor. The steps required to upload a file using Struts 2 are:

Step 1

Create the Struts 2 Action class. In our example we have called it FileUploadAction.java

An example of an action to upload a file:

package uk.co.spltech.web.actions;

import com.opensymphony.xwork2.Action;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;


/**
 * Uploads a file using Struts 2
 * 
 * @author Armindo Cachada
 */
public class FileUploadAction extends ActionSupport {
     private static final long serialVersionUID = 12323232L;
     private File file;
     private String fileFileName;
     private String fileContentType;
    
    
 public String execute() {

  return Action.SUCCESS;
 }
   
 public File getFile() {
        return this.file;
     }
 
  public void setFile(File file) {
         this.file = file;
      }

  public void setUpload(File file) {
      this.file = file;
   }
 /**
       * This method is called by the action.
       * Here you can do whatever you want with the uploaded file
       */
 public String upload() throws IOException  {
        File uploadedFile =this.getFile();
        // you can do whatever you want with the file
        return Action.SUCCESS;
 }


 public String getFileFileName() {
  return fileFileName;
 }

 public void setFileFileName(String fileFileName) {
  this.fileFileName = fileFileName;
 }

 public String getFileContentType() {
  return fileContentType;
 }

 public void setFileContentType(String fileContentType) {
  this.fileContentType = fileContentType;
 }

 public String getFileUrl() {
  return fileUrl;
 }

 public void setFileUrl(String fileUrl) {
  this.fileUrl = fileUrl;
 }
}

Step 2

Create the action in struts.xml

<action name="fileUpload" class="uk.co.spltech.web.actions.FileUploadAction" method="upload">
 <result>/success.jsp </result>
 <result type="error">/upload.jsp</result>   
</action>

Step 3

Create the jsp. For example:

Please select the file you want to upload:

 <s:form action="fileUpload" method="post" enctype="multipart/form-data" theme="simple">  
  <s:actionerror cssClass="errorMessage"/>
  <s:fielderror cssClass="error"/>
      <s:file name="upload" label="File"/>
     <s:submit/>   
 </s:form>

Step 3

The default maximum file size that struts 2 allows you to upload is only 2 megabytes. You can increase this size by specifying in struts.properties the struts.multipart.maxSize. This value is in bytes.
For example:

struts.multipart.maxSize=20480

Finally you can download the code for this example here.

Note that I didn't include the required struts2 library files with the example.
The files you need are:

commons-fileupload-1.2.1.jar
commons-io-1.3.2.jar
commons-logging.jar
freemarker-2.3.13.jar
ognl-2.6.11.jar
struts2-core-2.1.6.jar
xwork-2.1.2.jar
struts2-convention-plugin-2.1.6.jar

Click here to learn how to upload a file with Adobe Flex