Java web Servlet 笔记

1.servlet随Servlet容器启动就加载的方式<load-on-startup></load-on-startup>数字越小级别越高

<servlet>

    <description>This is the description of my J2EE component</description>

    <display-name>This is the display name of my J2EE component</display-name>

    <servlet-name>TestServlet1</servlet-name>

    <servlet-class>servlet.TestServlet1</servlet-class>

    <!-- 

    <load-on-startup>2</load-on-startup>

    -->

  </servlet>

 2.Servlet类文件被更新后，Servlet容器会自动加载Servlet

 3.Servlet与JSP九大内置对象

 4。绝对路径和相对路径
//请求重定向方式跳转到test.jsp,当前路径是ServletPathDirection/servlet/
//response.sendRedirect("test.jsp");--》error
//使用request.getContextPath获得上下文对象
    //response.sendRedirect(request.getContextPath()+"/test.jsp");

   //服务器内部跳转,这里的斜线表示项目的根目录
//request.getRequestDispatcher("/test.jsp").forward(request, response);

request.getRequestDispatcher("../test.jsp").forward(request, response);

5.Model1与Model2（MVC）