当Servlet程序中ServletConfig接口与ServletContext里面初始化参数比较多的时候，我们采用枚举的方式来更快的操作

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    ServletConfig config = this.getServletConfig();
    Enumeration<String> names = config.getInitParameterNames();
    while(names.hasMoreElements()){
        String nextElement = names.nextElement();
        String parameter = config.getInitParameter(nextElement);
        System.out.println(nextElement+"："+parameter);
    }

}