Java

Pre-Allocate Server Space Before an FTP Upload (ALLO)

Demonstrates the AllocateSize property, which sends the FTP ALLO command to pre-allocate disk space on the server before an upload. Set it to the size in bytes of the file about to be uploaded.

Background: ALLO asks the server to reserve storage in advance, a requirement of certain legacy systems — older mainframes in particular — that need the exact file size up front to allocate a dataset. Modern servers allocate space dynamically and typically ignore or accept ALLO without needing it, so most applications never set this. Provide it only when targeting a host known to require pre-allocation.

Chilkat Java Downloads

Download Chilkat for Java

Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Ftp2;

public class ChilkatExample {

    public static void main(String[] args) {
        Ftp2 ftp = new Ftp2();

        ftp.setHostname("ftp.example.com");
        ftp.setUsername("myFtpLogin");

        // Normally you would not hard-code the password in source.  You should instead obtain it
        // from an interactive prompt, environment variable, or a secrets vault.
        ftp.setPassword("myPassword");

        try {
            ftp.connect();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // AllocateSize sends the FTP ALLO command to pre-allocate disk space on the server before an
        // upload.  It is rarely needed -- mainly for certain legacy systems that require the exact size
        // in advance -- since most servers allocate space dynamically.  Set it to the size in bytes of
        // the file about to be uploaded.
ERROR: Assignment type mismatch.  ExpressionType=int, atgType=uint

        try {
            ftp.putFile("qa_data/bigfile.zip", "uploads/bigfile.zip");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Uploaded with pre-allocation.");

        try {
            ftp.disconnect();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }
    }
}