android正则表达式隐藏邮箱地址中间字符

//        String emailStr = email.substring(0, email.lastIndexOf("@"));
//        if (emailStr.length() < 2) {//0位、1位
////            String string=email.replaceAll("(\w?)(\w)(@\w+\.[a-z]+(\.[a-z]+)?)", "*$3");
//            return string;
//        } else if (2 <= emailStr.length() && emailStr.length() < 3) {//2位
////            return email.replaceAll("(\w?)(\w+)(\w)(@\w+\.[a-z]+(\.[a-z]+)?)", "$1*$3$4");
//        } else {//3位以上
////            return email.replaceAll("(\w?)(\w+)(\w)(@\w+\.[a-z]+(\.[a-z]+)?)", "$1*$3$4");
//        }