Invalid characters for http URL

Question

Can anyone tell me what are the invalid characters for HTTP URL and the best way to validate the same in Java. What I am looking for is URLString validation in the URL format: http(s)://ip:port/URLString

Thanks in advance.

Answer 1

You can use any unicode characters you want, as long as they are % encoded. The explicitly reserved characters are defined in section 2.2 of RFC3986: https://www.rfc-editor.org/rfc/rfc3986#section-2

From the document:

  reserved    = gen-delims / sub-delims

  gen-delims  = ":" / "/" / "?" / "#" / "[" / "]" / "@"

  sub-delims  = "!" / "$" / "&" / "'" / "(" / ")"
              / "*" / "+" / "," / ";" / "="