import java.net.*;

//以下皆為判斷語法

    String ip_Addr = request.getHeader("x-forwarded-for");  //登入者的ip address
//    String ip_Addr = request.getRemoteAddr();     //登入者的ip address，會取到portal的ip，故不用
    

   String vendorA = request.getHeader("referer");
//    取出hostname，例如: http://www.idealist.idv.tw/index.jsp，這裡host將得到 www.idealist.idv.tw
    int end = vendorA.indexOf("/", 7);
    String host = vendorA.substring(7, end);
//    由host去尋找出IP
    InetAddress inet = InetAddress.getByName(host);
    System.out.println("getHeaderNames = " + request.getHeaderNames());
    System.out.println("vendorA = " + vendorA);
    System.out.println("end = " + end);
    System.out.println("host = " + host);
    System.out.println("inet = " + inet);
    System.out.println("inet.getHostAddress() = " + inet.getHostAddress());
    System.out.println("getHeader(x-forwarded-for) = " + request.getHeader("x-forwarded-for"));
    System.out.println("getHeader(Proxy-Client-IP) = " + request.getHeader("Proxy-Client-IP"));