How can I mask the first 4 digits of a stringed number

Question

我想屏蔽字符串的前4位数字，例如1234567看起来像**** 567

Answer 1

You can use the substring function. Try something like that

 String number=1234567;
 String maskNumber="****"+number.substring(4);

Answer 2

怎么样：

"12345654".replaceFirst("[0-9]{4}", "****");

Answer 3

You could to this:

String str = "1234567";
String firstFourChars = str.substring(0, 4);
String newStr = str.replaceFirst(firstFourChars, "****");

Or to make it shorter:

str = str.replaceFirst(str.substring(0, 4), "****");