Java – accelerate Apache Commons ftpclient transfer

I use Apache Commons ftpclient to upload large files, but the transfer speed is only a small part of the transfer speed through FTP using winscp How can I speed up the transfer?

public boolean upload(String host,String user,String password,String directory,String sourcePath,String filename) throws IOException{

    FTPClient client = new FTPClient();
    FileInputStream fis = null;

    try {
        client.connect(host);
        client.login(user,password);
        client.setControlKeepAliveTimeout(500);

        logger.info("Uploading " + sourcePath);
        fis = new FileInputStream(sourcePath);        

        //
        // Store file to server
        //
        client.changeWorkingDirectory(directory);
        client.setFileType(FTP.BINARY_FILE_TYPE);
        client.storeFile(filename,fis);
        client.logout();
        return true;
    } catch (IOException e) {
        logger.error( "Error uploading " + filename,e );
        throw e;
    } finally {
        try {
            if (fis != null) {
                fis.close();
            }
            client.disconnect();

        } catch (IOException e) {
            logger.error("Error!",e);
        }
    }         
}

Solution

Increase buffer size:

client.setBufferSize(1024000);