Getting the class name without the full package

[Sat Nar]

Hi,
i have a small query.

public static void main(String[] args) {
// TODO Auto-generated method stub
String str = "Sairam";
Integer i = new Integer(1);
System.out.println(str.getClass().getName());
System.out.println(i.getClass().getName());

}

The below code returns the class name with the full package structure i.e

java.lang.String
java.lang.Integer

But if i need only the class name without the full package how do i do it?

Kindly help me out.

[Jeroen T Wenting]

split the name on a period and take the last element in the resulting string array.

[Joanne Neal]

Various options

1. String.split() - break up the package name and just use the last token
2. String.indexOf() - find the position of the last '.' and then use String.substring().
3. Get the name of the package (Class.getPackage().getName()) and then use the length of this with the String.substring() method.

[Peter Chase]

Originally posted by Joanne Neal:
3. Get the name of the package (Class.getPackage().getName()) and then use the length of this with the String.substring() method.

I'm not sure this will always work. I don't think every Class object has a Package object. Particularly not if loading with non-system ClassLoader.

[Mark Van Tuyl]

Originally posted by Joanne Neal:
2. String.indexOf() - find the position of the last '.' and then use String.substring().

Just a suggestion - String.lastIndexOf(".") will find the position of the last '.' in the String.

[Joanne Neal]

Originally posted by Mark Van Tuyl:
Just a suggestion - String.lastIndexOf(".") will find the position of the last '.' in the String.

Must get myself a proofreader

[Henry Wong]

Since I am a fan of regular expressions, I would like to add...

4. RegEx -- Use regular expressions to extract it

And to promote its usage, I'll even produce the code...

    private static String extractClassName (String fullname) {
        Pattern p = Pattern.compile(".*?([^.]+)$");
        Matcher m = p.matcher(fullname);
 
        return (m.find()) ? m.group(1) : "";
    }

Henry
[ April 25, 2006: Message edited by: Henry Wong ]

[Garrett Rowe]

Originally posted by Henry Wong:
RegEx -- Use regular expressions to extract it

And to promote its usage, I'll even produce the code...

    private static String extractClassName (String fullname) {
        Pattern p = Pattern.compile(".*?([^.]+)$");
        Matcher m = p.matcher(fullname);
 
        return (m.find()) ? m.group(1) : "";
    }

Henry

[ April 25, 2006: Message edited by: Henry Wong ]

Since you are not really interested in matching anything before the last '.' anyway, this regex could be reduced even further to:

  private static String extractClassName (String fullname)
  {
          Pattern p = Pattern.compile("[^.]+$");
          Matcher m = p.matcher(fullname);
 
          return (m.find()) ? m.group() : "";
  }

[Henry Wong]

Since you are not really interested in matching anything before the last '.' anyway, this regex could be reduced even further to:

Good point... I do seem to have a bad habit of matching everything before extracting.

Henry

[Jim Yingst]

Or you could use JDK 5, which has added Class.getSimpleName().
[ April 25, 2006: Message edited by: Jim Yingst ]