I am trying to verify if the string match a regular expression or not.
The URL format is : key=value&key=value&....
Key or value can be empty.
My code is :
Pattern patt = Pattern.compile("\\w*=\\w*&(\\w *=\\w*)* ");
Matcher m = patt.matcher(s);
if(m.matches()) return true;
else return false;
when i enter one=1&two=2, it shows false whereas it should show true.
Any idea !
The regex you need is
Pattern.compile("(?:\\w+=\\w*|=\\w+)(?:&(?:\\w+=\\w*|=\\w+))*");
See the regex demo. It will match:
(?:\\w+=\\w*|=\\w+) - either 1+ word chars followed with = and then 0+ word chars (obligatory key, optional value) or = followed with 1+ word chars (optional key)(?:&(?:\\w+=\\w*|=\\w+))* - zero or more of such sequences as above.String s = "one=1&two=2&=3&tr=";
Pattern patt = Pattern.compile("(?:\\w+=\\w*|=\\w+)(?:&(?:\\w+=\\w*|=\\w+))*");
Matcher m = patt.matcher(s);
if(m.matches()) {
System.out.println("true");
} else {
System.out.println("false");
}
// => true
To allow whitespaces, add \\s* where needed. If you need to also allow non-word chars, use, say, [\\w.-] instead of \w to match word chars, . and - (keep the - at the end of the character class).
if A return true; else return false;withreturn A;"\\w+=\\w+(?:&\\w+=\\w+)*"regex. The\w+will match 1 or more word chars,\w*would allow an empty string. Well, maybe you really want to allow=&=&=&=, no idea. Then use"\\w*=\\w*(?:&\\w*=\\w*)*". What are the requirements?. BTW, added another dupe - Validate URL query string with regex.=?