Regular expression to truncate a String

Question

To truncate a String here is what I'm using :

String test1 = "this is test truncation 1.pdf";     
String p1 = test1.substring(0, 10) + "...";
System.out.println(p1);

The output is 'this is te...' How can I access the file name extension so that output becomes : 'this is te... pdf' I could use substring method to access the last three characters but other file extensions could be 4 chars in length such as .aspx

Is there a regular expression I can use so that "this is test truncation 1.pdf" becomes "this is te... pdf"

Answer 1

You can do it all with a quick regex replace like this:

test1.replaceAll("(.{0,10}).*(\\..+)","$1...$2")

Answer 2

Do it like this :

String[] parts = test1.split("\\.");
String ext = parts[parts.length-1];
String p1 = test1.substring(0, 10) + "..."+ext;
System.out.println(p1);