timerfilter.java

过滤器技术的开发与设计。

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author unascribed
 * @version 1.0
 */

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class TimerFilter implements Filter {
  private FilterConfig config = null;

  public void init(FilterConfig config) throws ServletException {
    this.config = config;
  }

  public void destroy() {
    config = null;
  }

  public void doFilter(ServletRequest request, ServletResponse response,
                     FilterChain chain) throws IOException, ServletException {
    long before = System.currentTimeMillis();

    request.setCharacterEncoding("GBK");

    chain.doFilter(request, response);

    long after = System.currentTimeMillis();
    String name = "";

    if (request instanceof HttpServletRequest) {
      name = ((HttpServletRequest)request).getRequestURI();

    }

    config.getServletContext().log(name + ": " + (after - before) + "ms");
  }

}