import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
public static void main(String[] args) {
final String regex = "(?=(?:....)*$)";
final String string = "<html>\n"
+ "<head>\n"
+ "<title>Credit Card Test</title>\n"
+ "</head>\n\n"
+ "<body>\n"
+ "<h1>Credit Card Test</h1>\n\n"
+ "<form>\n"
+ "<p>Please enter your credit card number:</p>\n\n"
+ "<p><input type=\"text\" size=\"20\" name=\"cardnumber\"\n"
+ " onkeyup=\"validatecardnumber(this.value)\"></p>\n\n"
+ "<p id=\"notice\">(no card number entered)</p>\n"
+ "</form>\n\n"
+ "<script>\n"
+ "function validatecardnumber(cardnumber) {\n"
+ " // Strip spaces and dashes\n"
+ " cardnumber = cardnumber.replace(/[ -]/g, '');\n"
+ " // See if the card is valid\n"
+ " // The regex will capture the number in one of the capturing groups\n"
+ " var match = /^(?:(4[0-9]{12}(?:[0-9]{3})?)|(5[1-5][0-9]{14})|↵\n"
+ "(6(?:011|5[0-9]{2})[0-9]{12})|(3[47][0-9]{13})|(3(?:0[0-5]|[68][0-9])↵\n"
+ "[0-9]{11})|((?:2131|1800|35[0-9]{3})[0-9]{11}))$/.exec(cardnumber);\n"
+ " if (match) {\n"
+ " // List of card types, in the same order as the regex capturing groups\n"
+ " var types = ['Visa', 'MasterCard', 'Discover', 'American Express',\n"
+ " 'Diners Club', 'JCB'];\n"
+ " // Find the capturing group that matched\n"
+ " // Skip the zeroth element of the match array (the overall match)\n"
+ " for (var i = 1; i < match.length; i++) {\n"
+ " if (match[i]) {\n"
+ " // Display the card type for that group\n"
+ " document.getElementById('notice').innerHTML = types[i - 1];\n"
+ " break;\n"
+ " }\n"
+ " }\n"
+ " } else {\n"
+ " document.getElementById('notice').innerHTML = '(invalid card number)';\n"
+ " }\n"
+ "}\n"
+ "</script>\n"
+ "</body>\n"
+ "</html>\n";
final String subst = "-";
final Pattern pattern = Pattern.compile(regex);
final Matcher matcher = pattern.matcher(string);
// The substituted value will be contained in the result variable
final String result = matcher.replaceAll(subst);
System.out.println("Substitution result: " + result);
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html