JSP之操作request范围的属性实战

- 日理万妓 2021-07-25 02:54 372阅读 0赞

**一 draw.jsp**

<%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title> 取钱的表单页 </title>
        <meta name="website" content="http://www.crazyit.org" />
    </head>
    <body>
    
    <form method="post" action="first.jsp">
        取钱：<input type="text" name="balance">
        <input type="submit" value="提交">
    </form>
    </body>
    </html>

**二 first.jsp**

<%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %>
    <%@ page import="java.util.*" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title> request处理 </title>
        <meta name="website" content="http://www.crazyit.org" />
    </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 + "块");
        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);
    %>
    
    <jsp:forward page="second.jsp"/>
    <%}%>
    </body>
    </html>

**三 second.jsp**

<%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %>
    <%@ page import="java.util.*" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title> request处理 </title>
        <meta name="website" content="http://www.crazyit.org" />
    </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 + "块");
    out.println("账户减少" + qian);
    %>
    </body>
    </html>

**四 测试**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70]: /images/20210724/4fab5dee81f1449f8fe42377b7896de9.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1]: /images/20210724/04d3f8bc49e1454ba14f4731e4a42f55.png