ant = new AntBuilder()
ant.ftp( server:"ftp.foo.com",
    userid:"user",
    password:"passwd",
    passive:"yes",
    verbose:"yes",
    action:"get',
    remotedir:"/pub/incoming",
    binary:"yes" ) {
        fileset( dir:"." ) {
            include( name:"**/*.gz" )
        }
    }

http://blog.hhhhq.org/2007/04/ftp-using-groovy-and-ant.html

This script will alow you to download files from a remote FTP

Download Files from FTP (Groovy ANT Task)

script, groovy

Groovy