有没有按照本节课的思想进行编程？

InputNum.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
 <form action="http://localhost:8888/Servlet_advanced/test2_6/do" method="get">
  <input type="text" name="num" placeholder="请输入100以内的数字">
  <input type="submit" value="求累加和">
 </form>
</body>
</html>

DoServlet.java

package com.imooc.servlet.test2_6;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * Servlet implementation class DoServlet
 */
@WebServlet("/test2_6/do")
public class DoServlet extends HttpServlet {
 private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public DoServlet() {
        super();
        // TODO Auto-generated constructor stub
    }
 /**
  * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  response.setContentType("text/html;charset=utf-8");
  String str = request.getParameter("num");
  int num = Integer.parseInt(str);
  int sum = 0;
  for(int i = 0; i <= num; i++) {
   sum+= i;
  }
  request.setAttribute("num",num);
  request.setAttribute("result",sum);
  request.getRequestDispatcher("/test2_6/show").forward(request, response);
 }
}

ShowResult.java

package com.imooc.servlet.test2_6;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * Servlet implementation class InputNum
 */
@WebServlet("/test2_6/show")
public class ShowResult extends HttpServlet {
 private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ShowResult() {
        super();
        // TODO Auto-generated constructor stub
    }
 /**
  * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  response.setContentType("text/html; charset=utf-8");
  int num = (int)request.getAttribute("num");
  int result = (int)request.getAttribute("result");
  response.getWriter().println("0到"+num+"的累加和为："+result);
 }
}

懒人13 2019-07-24

源自：Servlet与JSP进阶 2-6 自由编程