FTP URL Regex for Java
/^ftps?://(?:[a-zA-Z0-9._~!$&'()*+,;=%-]+(?::[a-zA-Z0-9._~!$&'()*+,;=%-]*)?@)?(?:[a-zA-Z0-9\-]+\.)+[a-zA-Z]{2,63}(?::[1-9][0-9]{0,4})?(?:/[^\s]*)?$/iWhat this pattern does
This page provides a comprehensive, battle-tested regular expression for matching ftp url, ported and verified for Java. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.
Java Implementation
// FTP URL
// ReDoS-safe | RegexVault — Web & Network > URL
import java.util.regex.Pattern;
public class FtpUrlValidator {
private static final Pattern PATTERN =
Pattern.compile("^ftps?://(?:[a-zA-Z0-9._~!$&\'()*+,;=%-]+(?::[a-zA-Z0-9._~!$&\'()*+,;=%-]*)?@)?(?:[a-zA-Z0-9\\-]+\\.)+[a-zA-Z]{2,63}(?::[1-9][0-9]{0,4})?(?:/[^\\s]*)?$");
public static boolean validate(String input) {
return PATTERN.matcher(input).matches();
}
// Example
public static void main(String[] args) {
System.out.println(validate("ftp://files.example.com")); // true
}
}Test Cases
Matches (Valid) | Rejects (Invalid) |
|---|---|
ftp://files.example.com | http://example.com |
ftp://user:pass@ftp.example.com/files/ | sftp://example.com |
ftps://secure.ftp.example.com:990 | ftp:// |
ftp://ftp.example.com:21/pub/readme.txt | ftp:/example.com |
ftps://files.example.com/data.csv | ftp://user@ |
When to use this pattern
This pattern is drawn from the Web & Network > URL category and carries a ReDoS-safe certification. That matters for Java developers because critical in Java applications since the JVM regex engine uses backtracking and is susceptible to ReDoS without careful pattern design. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.
Common Pitfalls
SFTP (SSH File Transfer Protocol) uses an entirely different URL scheme (ssh://) and is unrelated to FTP. Do not conflate FTPS and SFTP.
Technical Notes
Credentials in URLs are a security risk — prefer separate authentication mechanisms. FTPS (FTP over SSL) typically uses port 990.
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