How to download file from FTP using Java?

问题:

With this code iI always get a empty file.
What I have to do with it?
login is always true. (ofc, here is not real password)

import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;

import java.io.*;

public class Logs {
    public static void main(String[] args) {
        FTPClient client = new FTPClient();

        try {
            client.connect("myac.cs-server.pro", 121);
            boolean login = client.login("a3ro", "passWordIsSecret");
            System.out.println(login);
            String remoteFile1 = "myac_20150304.log";
            File downloadFile1 = new File("C:\\Users\\Aero\\Desktop\\test\\myac.log");
            OutputStream outputStream1 =
                new BufferedOutputStream(new FileOutputStream(downloadFile1));
            boolean success = client.retrieveFile(remoteFile1, outputStream1);
            System.out.println(success);
            outputStream1.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                client.disconnect();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

回答1:

Use something like this:

InputStream inputStream = client.retrieveFileStream(remoteFileNameHere);

To retrieve the remote file input stream.

Then you can use to copy the stream to desired file:

 FileOutputStream out = new FileOutputStream(targetFile);
 org.apache.commons.io.IOUtils.copy(in, out);

回答2:

Use FileOutputStream:

String filename = "test.txt";
FileOutputStream fos = new FileOutputStream(filename);
client.retrieveFile("/" + filename, fos);