吴裕雄--天生自然JAVA开发JSP-Servlet学习笔记:操作request范围的属性

<%-- 
    Document   : draw
    Created on : 2020-4-12, 7:19:39
    Author     : Administrator
--%>

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title> 取钱的表单页 </title>
    </head>
    <body>
        <!-- 取钱的表单 -->
        <form method="post" action="first.jsp">
            取钱:<input type="text" name="balance">
            <input type="submit" value="提交">
        </form>
    </body>
</html>

<%-- 
    Document   : first2
    Created on : 2020-4-12, 7:26:42
    Author     : Administrator
--%>

<%@page import="java.util.List"%>
<%@page import="java.util.ArrayList"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title> request处理 </title>
    </head>
    <body>
        <%
// 获取请求的钱数
            String bal = request.getParameter("balance");
// 将钱数的字符串转换成双精度浮点数
            double qian = Double.parseDouble(bal);
// 对取出的钱进行判断
            if (qian < 500) {
                out.println("给你" + qian + "");
                out.println("账户减少" + qian);
            } else {
                // 创建了一个List对象
                List<String> info = new ArrayList<String>();
                info.add("1111111");
                info.add("2222222");
                info.add("3333333");
                // 将info对象放入request范围内
                request.setAttribute("info", info);
        %>
        <!-- 实现转发 -->
        <jsp:forward page="second.jsp"/>
        <%}%>
    </body>
</html>

<%-- 
    Document   : second
    Created on : 2020-4-12, 7:31:12
    Author     : Administrator
--%>

<%@page import="java.util.List"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title> request处理 </title>
    </head>
    <body>
        <%
// 取出请求参数
            String bal = request.getParameter("balance");
            double qian = Double.parseDouble(bal);
// 取出request范围内的info属性
            List<String> info = (List<String>) request.getAttribute("info");
            for (String tmp : info) {
                out.println(tmp + "<br/>");
            }
            out.println("取钱" + qian + "");
            out.println("账户减少" + qian);
        %>
    </body>
</html>

原文地址:https://www.cnblogs.com/tszr/p/12683596.html