麻烦高手给我注释一下此程序代码，万分感谢

//当使用get方式传递时讲转换成post方法
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request,response);
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/html;charset=gb2312");//返回的内容格式是html格式,字符的格式为gb2312
request.setCharacterEncoding("gb2312");//传递过来的参数也一gb2312编码
PrintWriter out = response.getWriter()//创建一个输出流

//这一传其实就是赋值，request.getParameter是在post传递方式中最常用的获取值的方法，后面的名称所对应的是之前提交表单内各输入框中定义的name值
String username=request.getParameter("username");
String password=request.getParameter("password");
String rname=request.getParameter("rname");
String nian=request.getParameter("nian");
String yue=request.getParameter("yue");
String ri=request