Hi,
The oreilly upload library has built in check for file existence
and renaming mechanism. I believe that the default is that if you upload
foo and it's already there it calls it foo.1.
Why don't you either use that mechanism or "borrow" some of the code to do
what you want?
On Wed, Oct 02, 2002 at 06:05:31PM +0800, hugo wrote:
> Hi
>
> I have a jsp file where I would like download files to a particular
> directory on the server.
>
> I am have form fields, including file upload fields, the content of
> which is forwarded to a second jsp where I use MultipartRequest from the
> com.oreilly.servlet.* package to download the uploaded files to a
> location on the server.
>
> This all works well, but I would like to check first if file(s) with the
> same filename already exists in that directory on the server. This can
> be done by executing a unix command on the server and getting the
> filenames from the directory.
>
> So far so good. However, the moment I use MultipartRequest to get the
> names of the files that are uploaded (to compare them with the ones
> already in the directory), they are immediately downloaded to the
> directory.
>
> So I thought I use MultipartParser first to obtain the filenames - but
> the moment I do this, I am using the generic method HttpServlet request
> and this means that, when using MultipartParser early in the jsp it
> seems I can no longer use MultipartRequest afterwards and vice versa (if
> there's a solution to this, please let me know).
>
> This led me to try to make the part that checks existing filenames
> agains the filenames in the upload fields into a javaBean - I can then
> call the Bean's method that does the checking from my second jsp file
> (to which form variables are forwarded). The bean would simply return a
> string containing "yes" of "no" depending on whether the filenames to be
> stored are unique or not.
>
> However, I have to pass the contents of the fields that contains the
> filenames to the bean - which means I have to once more use a request
> method to get those values in the first place.
>
> So the problem is that somehow I have to pass on HttpServlet request
> values to the bean, and I am not sure how to do this without getting the
> values out first with MultiPartParser - which makes it impossible for me
> to use MultipartRequest.
>
> The bean is listed in my jsp file as:
>
> <jsp:useBean id="checkupload" scope="session"
> class="com.geoinformex.project.checkUpload"/>
>
> and I am calling its method further down in the jsp:
>
> String samefile = checkupload.getdoCheck(BUT HERE I NEED TO PASS IN A
> REQUEST!);
>
> I have to pass in the request (parameter of file to be uploaded) to the
> bean - have a look at the method below in the bean itself. Note that
> without making the bean extend HttpServlet I cannot construct
> MultipartParser parser in the Bean's method getdoCheck later on.
>
> Complex problem, I know, but I am sort of hoping someone can set me back
> on the right path, as at this stage I am really lost as how to proceed.
>
> Any help, particularly code examples will be greatly appreciated.
>
> Thanks very much.
>
> Hugo
>
> ***
> Here is the bean:
>
> package com.geoinformex.project;
> import java.io.*;
> import java.text.*;
> import java.util.*;
> import javax.servlet.*;
> import javax.servlet.http.*;
> import java.sql.*;
> import com.oreilly.servlet.*;
> import com.oreilly.servlet.multipart.*;
> import com.oreilly.servlet.multipart.MultipartParser;
>
> public class checkUpload extends HttpServlet{
>
> //String lineOfText ="";
> String proj_id_b ="";
> String proj_id ="";
> //String makedir ="";
> int proj_id_count = 0;
> Vector proj_id_number = new Vector();
> Vector proj_id_base = new Vector();
> Vector project_ID_list = new Vector();
> Vector existingfiles = new Vector();
>
> String upload1 = "";
> String upload2 = "";
> String upload3 = "";
> Part part;
>
> public String getdoCheck(HttpServletRequest request,HttpServletResponse
> response) throws IOException, ServletException {
>
> String samefile = "";
>
> //Trying to get the filenames from the upload fields from my form (but
> this fails).
>
> MultipartParser parser = new MultipartParser(request, 10*1024*1024);
> while ((part = parser.readNextPart()) != null) {
> if (part.isFile()) {
> // It's a file part I am after
> FilePart filePart = (FilePart) part;
> String fileName = filePart.getFileName();
> if (fileName != null) {
> existingfiles.add(fileName);
> System.out.println("filename: " + fileName);
> }
> }
> }
>
> // Reading in filenames from the directory.
>
> try {
> Process p = Runtime.getRuntime().exec("ls /var/www/projects_data/");
> BufferedReader stdInput = new BufferedReader(new
>
> InputStreamReader(p.getInputStream()));
> String s = "";
> BufferedReader stdError = new BufferedReader(new
> InputStreamReader(p.getErrorStream()));
> while ((s = stdInput.readLine()) != null) {
> System.out.println ("<br>line of input is: " + s);
> StringTokenizer tr = new StringTokenizer(s," ", true );
> String t = tr.nextToken();
> System.out.println("<br>token is: "+ t);
> for (int i = 0; i < existingfiles.size(); i++) {
>
> //Comparing filenames obtained from directory with
> those obtained from file input fields.
>
> if (t.equals(existingfiles.get(i).toString())) {
> samefile = "yes";
> } else {
> samefile = "no";
> }
> }
> }
> } catch (IOException e) {
> System.out.println("exception: ");
> e.printStackTrace();
> System.exit(-1);
> }
> return samefile;
> }
> }
>
>
> --
> Dr Hugo Bouckaert
> Systems and Programming Engineer
>
> GeoInformatics Exploration Australia P/L
> 57 Havelock St
> West Perth, WA 6005
> PO Box 1675, West Perth 6872
>
> Ph: 61 08 9420 7400
> Fax: 61 08 9226 1299
>
> www.geoinformex.com
>
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