Struts simplify the file uploading process really easy.
You dont need third party stuff; just a few lines of code and a couple of tricks
will do the job :)
I have included a sample project for you to download and experiment with.
Key parts are :
1. Your form that will include the <html:file> tag, must be configured to handle multipart/form-data and to POST the data to the server, eg :
<html:form enctype="multipart/form-data" method="POST" action="upload.do">
2. The form bean that will handle the uploading, must have a property for the file been uploaded set like this :
<form-property name="filename" type="org.apache.struts.upload.FormFile">
After that, coding is really simple. I have included a complete project for uploads at the end of this post.
Here follows the java source part for the upload file process:
package fileuploader.view;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.DecimalFormat;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.DynaActionForm;
import org.apache.struts.upload.FormFile;
public class UploadAction extends Action
{
/**
* This is the main action called from the Struts framework.
* @param mapping The ActionMapping used to select this instance.
* @param form The optional ActionForm bean for this request.
* @param request The HTTP Request we are processing.
* @param response The HTTP Response we are processing.
* @throws javax.servlet.ServletException
* @throws java.io.IOException
* @return
*/
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException, Exception
{
String toPage = "";
DynaActionForm df = null;
FormFile webFile = null;
FileOutputStream ServerFileStream = null;
File SaveToFile = null;
int FILE_SIZE_LIMIT = 5000000;
double filesize = 0 ;
try
{
//convert to a DynaActionForm
df = (DynaActionForm) form;
//class cast to a struts type FormFile filename
webFile = (FormFile) df.get("filename");
//get the size of the file that user wants to upload
filesize = webFile.getFileSize();
//i have included a file size limitation in this version
if (filesize > FILE_SIZE_LIMIT )
{
//format the size of the file to return two decimals
String pattern = "####.##";
DecimalFormat dblFormat = new DecimalFormat(pattern);
//file size returned to megabytes
String strFileSize = dblFormat.format((filesize / 1024) / 1024);
//redirect to the page that informs the user that there is a
//file size limitation
toPage = "filesizepage";
request.setAttribute("fsize", strFileSize);
return mapping.findForward(toPage);
}
//get the real path of the project
String strFilePath = getServlet().getServletContext().getRealPath("/");
//we want to upload to UploadedFiles directory
strFilePath = strFilePath + "UploadedFiles";
//initialize a file to write to
SaveToFile = new File(strFilePath, webFile.getFileName());
//in this version, if the file to upload already exists on the server
//i delete the server-side one and reupload it
if(SaveToFile.exists())
{
//delete the file
SaveToFile.delete();
}
//save the file to server
ServerFileStream = new FileOutputStream(SaveToFile);
ServerFileStream.write(webFile.getFileData());
ServerFileStream.flush();
ServerFileStream.close();
ServerFileStream = null;
toPage="success";
}
catch(Exception e)
{
//just print the trace
e.printStackTrace();
//and redirect to an error page
toPage = "error";
}
finally
{
//release resources
df = null;
webFile = null;
ServerFileStream = null;
SaveToFile = null;
}
return mapping.findForward(toPage);
}
}
Download the full jdeveloper sample project
(right-click and select "save target as")
just remember to rename it to .rar |
Author's note : Thank you all for your supporting letters. You have been a motivation to this web spot's posting. I wish you all the
very best for you and your families for the new year.
Thanks for the source man