java 手机号/身份证（*）加密隐藏中间某几位几位

 String phone = "18771632488";  
        System.out.println(phone.replaceAll("(\\d{3})\\d{4}(\\d{4})","$1****$2"));  

 String idCard = "421302199208165464";
 System.out.println(idCard.replaceAll("(\\d{4})\\d{10}(\\d{4})", "$1****$2"));