Specific string format in java

Question

I want to validate a String in java that contains the following order:

SAVA950720HMCLZL04

That is, four letters, six numbers, six letters and finally two numbers.

I was reading about Regular Expressions but I can't understand how to implement it.

I did this method to validate the first four letters.

 public void name(String s){
 Pattern pat=Pattern.compile("[a-zA-z]{4}");
 Matcher mat=pat.matcher(curp);
 if(mat.matches()){
     JOptionPane.showMessageDialog(null, "Validating");
 }else{
     JOptionPane.showMessageDialog(null, "Check your data. please", "error",JOptionPane.ERROR);
 }
 }

I think that I might be wrong because I don't know how to implement it correctly, any help about what might be the correct solution to my problem?.

Note that [A-z] matches more than just letters. The matches() method anchors the regex, so you can only match strings of 4 chars. So, you need matches("[A-Za-z]{4}[0-9]{6}[A-Za-z]{6}[0-9]{2}") — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Mar 6, 2017 at 21:09
A-z should be A-Z. To represent digits use [0-9] or \d (in String literals you need to additionally escape \ so it will look like "\\d"). Also matches() checks if regex can match entire string, not just part of it. — Pshemo
– Pshemo, Commented Mar 6, 2017 at 21:10

Community · Accepted Answer · 2017-05-23 10:30:06Z

2

Regex pattern in your case would be:

[a-zA-Z]{4}[0-9]{6}[a-zA-Z]{6}[0-9]{2}

Find matching is simple:

public void name(String s){
    String pattern = "[a-zA-Z]{4}[0-9]{6}[a-zA-Z]{6}[0-9]{2}";
    boolean match = s.matches(pattern);
    if (match) {
        ...
    } else {
        ...
    }
}

You can test regex from here https://regex101.com/

Edit

I used [0-9] instead of \d to ensure the safety matching for only digits. More details can be found here: Should I use \d or [0-9] to match digits in a Perl regex?

edited May 23, 2017 at 10:30

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answered Mar 6, 2017 at 21:18

AttitudeL

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Comments

hoaz · Accepted Answer · 2017-03-06 21:20:22Z

0

Matcher.match attempts to match entire String against the pattern and your current pattern validates only 4 characters. Here is what you can do to test you regular expression:
- You can put .* at the end of regular expression to match rest of the String
- You can alternatively use Matcher.find or Matcher.lookingAt to match against substring
Your pattern has a typo, second interval is too wide A-z vs A-Z

edited Mar 6, 2017 at 21:20

answered Mar 6, 2017 at 21:15

hoaz

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Comments

micfra · Accepted Answer · 2017-03-06 21:21:56Z

0

package com.stackoverflow._42635543;

import java.util.regex.Pattern;

public class Main {

  public static void main(String[] args) {
    Pattern pat = Pattern.compile("[A-Za-z]{4}[0-9]{6}[A-Za-z]{6}[0-9]{2}");

    if (pat.matcher("SAVA950720HMCLZL04").matches()) {
        System.out.println("match");
    } else {
        System.out.println("no match");
    }

    if (pat.matcher("SAVA950720HMCLZL045").matches()) {
        System.out.println("match");
    } else {
        System.out.println("no match");
    }
  }
}

produces

match
no match

answered Mar 6, 2017 at 21:21

micfra

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Comments

Sash Sinha · Accepted Answer · 2017-03-06 21:23:17Z

0

Try this Regex pattern:

[a-zA-Z]{4}\d{6}[a-zA-Z]{6}\d{2}

The above will validate for four letters, six numbers, six letters and finally two numbers.

edited Mar 6, 2017 at 21:23

Sash Sinha

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answered Mar 6, 2017 at 21:17

ISHIDA

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