How do I check if a string is a valid md5 or sha1 checksum string

Question

I don\'t want to calculate a file\'s checksum, just to know if a given string is a valid checksum

Answer 1

RegExp SHA-1

public static final String SHA_1 = "^([0-9A-Fa-f]{2}[:]){19}([0-9A-Fa-f]{2})$";

public boolean isValidSHA1(String s) {
    return s.matches(SHA_1);
}

boolean isValidSHA1 = isValidSHA1("12:45:54:3A:99:24:52:EA...");