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

public class HeaderSnoop extends HttpServlet {

  public void doGet(HttpServletRequest req, HttpServletResponse res)
                               throws ServletException, IOException {
    res.setContentType("text/plain");
    PrintWriter out = res.getWriter();

    out.println("Request Headers:");
    out.println();
    Enumeration names = req.getHeaderNames();
    while (names.hasMoreElements()) {
      String name = (String) names.nextElement();
      Enumeration values = req.getHeaders(name);  // support multiple values
      if (values != null) {
        while (values.hasMoreElements()) {
          String value = (String) values.nextElement();
          out.println(name + ": " + value);
        }
      }
    }
  }
}