Java code to enforce to have number and character in Jtextfield

Question

I have Jtextfield, I want to format it, so that it should accept in the format below.

KYC123456L

Input will always start with "KYC" and ends with "L" and 6 numbers in between.

UI has a button that will copy the contents of other components and save it to a text file. But before it copies it should validate the jtextfield and copy if only format above matches, if not a message to be displayed.

Please suggest.

Answer 1

Frame the regex: ^KYC[0-9]{6}L$ to match the pattern stated in your question.

It'll match the strings starting with KYC, then 6 digits, and finally ending with L.

_{NOTE: ^ marks the beginning of the string, whereas $ marks the end of the string.}

String patternString = "^KYC[0-9]{6}L$";
Pattern p = Pattern.compile(patternString);
String test = jTextField.getText();
Matcher m = p.matcher(test);
boolean matches = m.matches();
if(matches == true)
  // allow
else
  // JOptionpane.showMessageDialog ---> your desired error message.