How to delete one existing file before uploading a file with same name?

Question

Hello everybody.
I am uploading a file to Tomcat server. But, the problem is:
i want to delete an existing file in the server, if i upload a fresh file with same name. In other words, "First check for the file with the same name in the server. If it exists, then delete existing file in the server and upload fresh one". If such file doesnot exist, then upload the file to server.
I have given deleteonExit()
but, for the first time when user is uploading, i want to check for the file with same name in the server.
i am pasting the code here. please help:
<!-- uploading the file -->
<%
String contentType = request.getContentType();
if ((contentType != null) && (contentType.indexOf("multipart/form-data") >= 0))
DataInputStream in = new DataInputStream(request.getInputStream());
int formDataLength = request.getContentLength();
byte dataBytes[] = new byte[formDataLength];
int byteRead = 0;
int totalBytesRead = 0;
while (totalBytesRead < formDataLength)
byteRead = in.read(dataBytes, totalBytesRead, formDataLength);
totalBytesRead += byteRead;
String contextRootPath = this.getServletContext().getRealPath("/");
contextRootPath=contextRootPath.concat("uploaded");
String file = new String(dataBytes);
String saveFile = file.substring(file.indexOf("filename=\"") + 10);
saveFile = saveFile.substring(0, saveFile.indexOf("\n"));
saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,saveFile.indexOf("\""));
// Create a directory; all ancestor directories must exist
File outputFile = new File(contextRootPath, saveFile);
var=outputFile.getPath();
outputFile.createNewFile();
int lastIndex = contentType.lastIndexOf("=");
String boundary = contentType.substring(lastIndex + 1,contentType.length());
int pos;
pos = file.indexOf("filename=\"");
pos = file.indexOf("\n", pos) + 1;
pos = file.indexOf("\n", pos) + 1;
pos = file.indexOf("\n", pos) + 1;
int boundaryLocation = file.indexOf(boundary, pos) - 4;
int startPos = ((file.substring(0, pos)).getBytes()).length;
int endPos = ((file.substring(0, boundaryLocation)).getBytes()).length;
FileOutputStream fileOut = new FileOutputStream(outputFile);
fileOut.write(dataBytes, startPos, (endPos - startPos));
fileOut.flush();
fileOut.close();
outputFile.deleteOnExit();
%>Please help. Thanks for taking time.
Regards,
Ashvini

Answer 1

Thank you MartinHilpert,
I have one more doubt,
I am uploading the file to one folder called "uploaded". Before uploading a fresh file, i want to delete all existing files in that folder. IS that possible ?? If yes, can you please tell me how to do that ??
Regards, Thanks for your time.
Ashlvini