자바에서 정규식을 이용하여 휴대폰 번호 가운데 마스킹하기

private static final String MOBILE_PATTERN = "^(\\d{3})-?(\\d{3,4})-?(\\d{4})$";

@Test
public void mobileMaskingTest() {
    // 휴대폰번호 형식
    String mobile1 = "010-1234-5678";
    String mobile2 = "01012345678";

    System.out.println("휴대전화 : " + mobile(mobile1));
    System.out.println("휴대전화 : " + mobile(mobile2));
}
public String mobile(String mobile) {
    String replaceString = mobile;

    Matcher matcher = Pattern.compile(MOBILE_PATTERN).matcher(mobile);

    if(matcher.matches()) {
        replaceString = "";

        boolean isHyphen = false;
        if(mobile.indexOf("-") > -1) {
            isHyphen = true;
        }

        for(int i=1;i<=matcher.groupCount();i++) {
            String replaceTarget = matcher.group(i);
            if(i == 2) {
                char[] c = new char[replaceTarget.length()];
                Arrays.fill(c, '*');

                replaceString = replaceString + String.valueOf(c);
            } else {
                replaceString = replaceString + replaceTarget;
            }

            if(isHyphen && i < matcher.groupCount()) {
                replaceString = replaceString + "-";
            }
        }
    }
    return replaceString;
}

결과

휴대전화 : 010-****-5678

휴대전화 : 010****5678