Если это фильтр регистра веб-приложения, который регистрирует все запросы от клиента в некоторый файл.
web.xml:
<filter>
<filter-name>MyLogFilter</filter-name>
<filter-class>my.package.MyLogFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>MyLogFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
код:
public class MyLogFilter implements Filter {
private static final Logger log = Logger.getLogger(MyLogFilter.class);
public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
//Get the IP address of client machine.
String ipAddress = request.getRemoteAddr();
//Log the IP address and current timestamp.
log.info("IP "+ipAddress + ", Time "
+ new Date().toString());
chain.doFilter(req, res);
}