1. javax.servlet
   1. ServletRequest
      1. String getParemeter (String paramName)
      2. String[] getParameterValues (String paramName)
      3. Enumeration getparameterNames()
2. javax.servlet.http
   1. HttpServletRequest
      1. String getHeader (String headerName)
      2. Enumeration getHeaders (String headerName)
      3. Enumeration getHeaderNames()