There are whole books about regular expressions so this post shouldn’t be intended as an exhaustive resource on the subject. It just shows how to extract a substring from a string using regular expressions in JavaScript so it must be considered just a tip not a tutorial on RegExp. Look at the following example:
var str = "https://www.alessandrolacava.com/?code=ALE69"; var regex = /code=(w+)&?/; var results = regex.exec(str); if(!results){ alert("no match"); } else{ // first group alert(results[1]); } The previous code extracts the string that follows the code= part of str.
You can do that using the following pattern in the compile static method of the java.util.regex.Pattern class. The pattern is (.|n|r)*? which means: any character (the .) or (the |) n or r. Zero or more times (the *) of the whole stuff.
Example: The following method strips the multiline comments (those between /* and */) from a string passed in and returns the resulting string:
import java.util.regex; // ... other code // Strip multiline comments public void deleteMultilineComments(String subject) { Pattern pattern = Pattern.
When using RegEx in Java you might face the need of treating one or more metacharacters as ordinary characters. As a reminder the metacharacters in a Java RegEx are:
([{^$|)?*+.
If you want to treat them as ordinary characters you have two options:
Escape the metacharacter with a backslash, Enclose the whole string that contains metacharacters within Q and E Q means: “quotes all characters until E”, while E ends the quotes.