listener.java

import java.io.FileWriter;
import java.io.IOException;

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;


public class Logger implements HttpSessionListener{
	
	public void sessionCreated(HttpSessionEvent e){
        java.util.Date data = new java.util.Date(); 
        FileWriter writer = null;
        try {
            writer = new FileWriter( "log.txt" );
            writer.write( String.format( "Usuário logado em: %s%n", data ) );
            writer.flush();
        } catch (IOException e1) {
            e1.printStackTrace();
        } finally {
            if ( writer != null ) {
                try {
                    writer.close();
                } catch ( IOException e1 ) {
                    e1.printStackTrace();
                }
            }
        }		

		System.out.println("ativei");
  
	}
	
	public void sessionDestroyed(HttpSessionEvent e){
		System.out.println("desativei");
	}
}