随机抽取学号

idea 配置

抽学号

浏览器提交一个100 以内的整数。，后端接受后，根据提供的整数，产生 100 以内的

随机数，返回给浏览器？

前端：提供随机数范围，病发送请求
后端：处理随机数的产生，和响应至浏览器

添加web添加

html 复制代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
<form action="/chouxuehao/demo" method="get">
    请输入参与活动的总人数
    <br>
    <input type="text" name="renshu" placeholder="100以内的整数">
    <br>
    <input type="submit" value="确定活动人数">
    
</form>
</body>
</html>

创建artifacts

web.xml

xml 复制代码

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>aa</servlet-name>
        <servlet-class>com.yanyu.Demo</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>aa</servlet-name>
        <url-pattern>/demo</url-pattern>
    </servlet-mapping>
</web-app>

JDK8在线文档

后端

java 复制代码

package com.yanyu;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

public class Demo extends HttpServlet {
//    接受前端奇怪的活动总人数
//    产生随机数

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        设置编码格式
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html");
        response.setCharacterEncoding("utf-8");
//       获取响应对象
        PrintWriter out = response.getWriter();
//        huoqu 前段  数据
        String renshu = request.getParameter("renshu");//45
//        把字符串 转为  int
        int i = Integer.parseInt(renshu);



        int random =(int) (Math.random() * i);
        int i1 = random + 1;
//        out.print("中奖的是："+i1);

//        ======================
out.print("        <!DOCTYPE html>");
out.print("<html lang='en'>");
out.print("<head>");
out.print("    <meta charset='UTF-8'>");
out.print("    <meta name='viewport' content='width=device-width, initial-scale=1.0'>");
out.print("    <title>Document</title>");
out.print("</head>");
out.print("<body>");
out.print("                中奖的是：");
out.print("    <br>");
out.print("    <div style='color: red; font-size: 48px;'>");
out.print(i1);
out.print("    </div>");
out.print("</body>");
out.print("</html>");



    }
}