CODEWITHSUNDEEP
javaftpapache-commons-net
Karthik Deepan
Karthik Deepan

Reputation: 144

Download a files from FTP matching a wildcard using Java Apache Commons Net

Basically I need to download list of matching files for the search from a FTP server. I have the code to download a specific file from a FTP server. But I need to download all the matching files with my wildcard search. How is that possible in Java?

Here is code for file downloading of a specific filename, from a FTP server - 

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;
public class FTPDownloadFileDemowithoutmodandfilefilter {
    public static void main(String[] args) {
        String server = "test.rebex.net";
        int port = 21;
        String user = "demo";
        String pass = "password";
        FTPClient ftpClient = new FTPClient();
        try {
            ftpClient.connect(server, port);
            ftpClient.login(user, pass);
            ftpClient.enterLocalPassiveMode();
            ftpClient.setFileType(FTP.BINARY_FILE_TYPE);

            File localFile = new File("C:\\project\\readme1.txt");
            FTPFile remoteFile = ftpClient.mdtmFile("/readme.txt");
            if (remoteFile != null)
            {
                OutputStream outputStream =
                    new BufferedOutputStream(new FileOutputStream(localFile));
                if (ftpClient.retrieveFile(remoteFile.getName(), outputStream))
                {
                    System.out.println("File downloaded successfully.");
                }
                outputStream.close();

                localFile.setLastModified(remoteFile.getTimestamp().getTimeInMillis());
            }

        } catch (IOException ex) {
            System.out.println("Error: " + ex.getMessage());
            ex.printStackTrace();
        } finally {
            try {
                if (ftpClient.isConnected()) {
                    ftpClient.logout();
                    ftpClient.disconnect();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }

}

Upvotes: 7

Views: 3516

Answers (1)

Martin Prikryl
Martin Prikryl

Reputation: 202262

Use FTPClient.mlistDir (recommended, if the server supports it) or FTPClient.listFiles to retrieve list of files. And then filter them according to your needs.

The following example downloads all files matching a regular expression .*\.jpg:

FTPFile[] remoteFiles = ftpClient.listFiles(remotePath);

Pattern pattern = Pattern.compile(".*\\.jpg");
Stream<FTPFile> matchingFiles =
    Arrays.stream(remoteFiles).filter(
        (FTPFile remoteFile) -> pattern.matcher(remoteFile.getName()).matches());

for (Iterator<FTPFile> iter = matchingFiles.iterator(); iter.hasNext(); ) {
    FTPFile remoteFile = iter.next();
    System.out.println("Found file " + remoteFile.getName() + ", downloading ...");

    File localFile = new File(localPath + "\\" + remoteFile.getName());
    
    OutputStream outputStream =
        new BufferedOutputStream(new FileOutputStream(localFile));
    if (ftpClient.retrieveFile(remotePath + "/" + remoteFile.getName(), outputStream))
    {
        System.out.println(
            "File " + remoteFile.getName() + " downloaded successfully.");
    }
    outputStream.close();
}

Upvotes: 5

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