Java code to preallocate space for destination mainframe file using FTP

 
In my project I have faced a scenario such that , I need to upload a csv file from my java application to a mainframe system, I have Java code that uses the Apache commons net Ftp Client library to send a file to a mainframe. The code works perfectly for small sized files under 5 Mb. However, when it encounters a file over 5 Mb, it fails with a CopyStreamException.
 
** UPDATE: FTP Complete tutorial now available here.
 
Then I have gotten assistance from a mainframe expert, the mainframe person informed me that the format parameters and block-size of the file created on the mainframe were incorrect.
 
And so with the help of the mainframe expert , I have included the following codes in my ftp program,
 

ftpclient.sendSiteCommand("RECFM=FB");
ftpclient.sendSiteCommand("LRECL=2000");
ftpclient.sendSiteCommand("BLKSIZE=27000");
ftpclient.sendSiteCommand("CY");
ftpclient.sendSiteCommand("PRI= 50");
ftpclient.sendSiteCommand("SEC=25");

 
where
RECFM=FB -> record format , which implies the file format
LRECL=2000 -> Logical record length , which decides the length of a record
BLKSIZE=27000 -> Block size command use to set the block size of the content transferred
CY -> Allocated space in cylinders, and PRI= 50 is the primary allocation and SEC=25 is the secondary allocation , and RLSE is the release command.

Now my ftp program could able to transfer files over 5 MB to the main frame system.

 
File : FtpFileUpload.java
 

import java.io.IOException;
import java.io.File;
import java.io.FileInputStream;

import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPConnectionClosedException;

class FTPFileUpload
{
        public static void main(String[] args) throws IOException
        {
                FTPClient ftpclient = new FTPClient();
                FileInputStream fis = null;
                boolean result;
                String ftpServerAddress = "localhost";
                String userName = "admin";
                String password = "admin";

                try
                {
                    ftpclient.connect(ftpServerAddress);
                    result = ftpclient.login(userName, password);

                    if (result == true)
                    {
                    System.out.println("Logged in Successfully !");
                    }
                    else
                    {
                    System.out.println("Login Fail!");
                    return;
                    }
                ftpclient.setFileType(FTP.BINARY_FILE_TYPE);
                // preallocate space in mainframe server using FTP
                        ftpclient.sendSiteCommand("RECFM=FB");
                        ftpclient.sendSiteCommand("LRECL=2000");
                        ftpclient.sendSiteCommand("BLKSIZE=27000");
                        ftpclient.sendSiteCommand("CY");
                        ftpclient.sendSiteCommand("PRI= 50");
                        ftpclient.sendSiteCommand("SEC=25");
                        ftpclient.changeWorkingDirectory("/");

                        File file = new File("D:/File.csv");
                        String testName = "PUBLIC.FILENAME.FILE1";
                        fis = new FileInputStream(file);

                        // Upload file to the ftp server
                        result = ftpclient.storeFile(testName, fis);

                        if (result == true) {
                        System.out.println("File is uploaded successfully");
                        }
                        else {
                        System.out.println("File uploading failed");
                        }
                        ftpclient.logout();
                } catch (FTPConnectionClosedException e) {
                        System.out.println(e);
                } finally {
                        try {
                                ftpclient.disconnect();
                        } catch (FTPConnectionClosedException e) {
                                System.out.println(e);
                        }
                }
        }
}