显示电子邮件地址作为提示

Question

I have seen Mail services displays the email id's as e*****e@gmail.com , mostly in their recovery page.

So i am trying to replace the example@gmail.com as e*****e@gmail.com .

Is it possible to achieve it using String#replace(String) alone ? or should i use some REGEX to achieve it .

Thanks for your valuable suggestions in adavance

Answer 1

Search regex:

\b(\w)\S*?(\S)(?=@)(\S+)\b

Replacement Pattern:

$1****$2$3****$4

RegEx Demo

Code:

String email = "anexample@gmail.com"; 
String repl = email.replaceFirst("\\b(\\w)\\S*?(\\S@)(\\S)\\S*(\\S\\.\\S*)\\b", 
      "$1****$2$3****$4");
//=> a****e@g****l.com

Answer 2

It could be possible through replaceAll function.

(?<!^).(?=.*?.@)

Use the above regex and replace the matched characters with *

DEMO

String s = "example@gmail.com";
System.out.println(s.replaceAll("(?<!^).(?=.*?.@)", "*"));

Output:

e*****e@gmail.com

Update:

Use the below regex to get the output like e*****e@g***l.com

String s = "example@gmail.com";
System.out.println(s.replaceAll("\\B.\\B(?=.*?\\.)", "*"));

Output:

e*****e@g***l.com

Answer 3

You can try without regex too

 String email = "example@gmail.com";
 int start = 1;
 int end = email.indexOf("@") - 1;
 StringBuilder sb = new StringBuilder(email);
 StringBuilder sb1=new StringBuilder();
 for(int i=start;i<end;i++){
    sb1.append("*");
 }
 sb.replace(start, end, sb1.toString());
 System.out.println(sb.toString());

Out put:

 e*****e@gmail.com

Answer 4

I sugges to use indexOf and substring . With replace you can run into tuble with emails like gmail@gmail.com