WEB核心【案例：JSP回显信息】第七章
【摘要】
目录
1，JSP回显信息
1，1 引言
1，2 概述及格式
1，3 课堂案例
1，4 JSP作用域回显
1，5 JSP导包及集合回显
1，6 案例代码实现
1，JSP回显信息
1，1 引言
目标：熟练掌握JSP信息回显技术
想要进行题目要求的回显：
使用Servlet拼接字符串是可以实现的
举个例子：...
目录
1，JSP回显信息
1，1 引言
目标：熟练掌握JSP信息回显技术
想要进行题目要求的回显：
使用Servlet拼接字符串是可以实现的
举个例子：一个Servlet程序进行写入页面回显：缺点就是很有缺点基本没人用，写了个示例大家了解一下
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public void run1() throws IOException {
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boolean result = true;
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String str = "";
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if(result){
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str = "登录成功";
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}else{
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str = "登录失败";
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}
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PrintWriter w = getResponse().getWriter();
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w.write("<!DOCTYPE html>\n" +
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"<html lang=\"zh-CN\">\n" +
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"\t<head>\n" +
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"\t\t<meta charset=\"utf-8\">\n" +
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"\t\t<meta http-equiv=\"X-UA-Compatible\" content=\"IE=edge\">\n" +
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"\t\t<meta name=\"viewport\" content=\"width=device-width,initial-scale=1\" />\n" +
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"\t\t<title>传智商城-登录页面</title>\n" +
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"\n" +
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"\t\t<link href=\"css/bootstrap.min.css\" rel=\"stylesheet\">\n" +
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"\t\t<link rel=\"stylesheet\" href=\"css/bootstrap-theme.min.css\" />\n" +
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"\t\t<script src=\"js/jquery-1.11.3.min.js\"></script>\n" +
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"\t\t<script src=\"js/bootstrap.min.js\"></script>\n" +
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"\t</head>\n" +
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"\n" +
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"\t<body>\n" +
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"\t\t<!-- 网站头部 -->\n" +
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"\t\t<div class=\"container\">\n" +
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"\t\t\t<div class=\"row\">\n" +
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"\t\t\t\t<div class=\"col-md-4\">\n" +
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"\t\t\t\t\t<img src=\"img/czxyLogo.png\" />\n" +
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"\t\t\t\t</div>\n" +
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"\t\t\t\t<div class=\"col-md-4\">\n" +
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"\t\t\t\t\t<img src=\"img/header.png\"/> \n" +
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"\t\t\t\t</div>\n" +
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"\t\t\t\t<div class=\"col-md-4\" style=\"padding-top: 20px;\">\n" +
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"\t\t\t\t\t<ul class=\"list-inline\" >\n" +
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"\t\t\t\t\t\t<li><a href=\"login.html\" class=\"btn btn-primary glyphicon glyphicon-user\">登录</a></li>\n" +
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"\t\t\t\t\t\t<li><a href=\"register.html\" class=\"btn btn-danger glyphicon glyphicon-plus\">注册</a></li>\n" +
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"\t\t\t\t\t\t<li><a href=\"cart.html\" class=\"btn btn-primary glyphicon glyphicon-shopping-cart\" onmouseover=\"showCartItem(this)\">购物车<span class=\"badge\">5</span></a></li>\n" +
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"\t\t\t\t\t</ul>\n" +
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"\t\t\t\t</div>\n" +
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"\t\t\t</div>\n" +
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"\t\t</div>\n" +
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"\t\t\n" +
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"\t\t<!-- 头部导航条 -->\n" +
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"\t\t<div class=\"container\">\n" +
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"\t\t\t<div class=\"row\">\n" +
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"\t\t\t\t<div class=\"col-xs-12\">\n" +
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"\t\t\t\t\t<nav class=\"navbar navbar-inverse\">\n" +
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"\t\t\t\t\t <div class=\"container-fluid\">\n" +
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"\t\t\t\t\t <div class=\"navbar-header\">\n" +
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"\t\t\t\t\t <button type=\"button\" class=\"navbar-toggle collapsed\" data-toggle=\"collapse\" data-target=\"#bs-example-navbar-collapse-1\" aria-expanded=\"false\">\n" +
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"\t\t\t\t\t <span class=\"sr-only\">Toggle navigation</span>\n" +
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"\t\t\t\t\t <span class=\"icon-bar\"></span>\n" +
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"\t\t\t\t\t <span class=\"icon-bar\"></span>\n" +
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"\t\t\t\t\t <span class=\"icon-bar\"></span>\n" +
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"\t\t\t\t\t </button>\n" +
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"\t\t\t\t\t <a class=\"navbar-brand\" href=\"index.html\">首页</a>\n" +
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"\t\t\t\t\t </div>\n" +
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"\t\t\t\t\t\n" +
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"\t\t\t\t\t <div class=\"collapse navbar-collapse\" id=\"bs-example-navbar-collapse-1\">\n" +
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"\t\t\t\t\t <ul class=\"nav navbar-nav\">\n" +
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"\t\t\t\t\t <li class=\"active\"><a href=\"product_list.html\">手机数码<span class=\"sr-only\">(current)</span></a></li>\n" +
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"\t\t\t\t\t <li><a href=\"#\">电脑办公</a></li>\n" +
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"\t\t\t\t\t <li><a href=\"#\">家具家居</a></li>\n" +
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"\t\t\t\t\t </ul>\n" +
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"\t\t\t\t\t <form class=\"navbar-form navbar-right\" role=\"search\">\n" +
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"\t\t\t\t\t <div class=\"form-group\">\n" +
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"\t\t\t\t\t \t<div class=\"input-group\">\n" +
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" \t\t\t\t\t\t\t\t<input id=\"wordsSearch\" type=\"text\" class=\"form-control\" placeholder=\"Search\" onkeyup=\"searchWords(this)\" onclick=\"showWordsList()\">\n" +
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" \t\t\t\t\t\t\t\t<div class=\"input-group-addon\" onclick=\"itemulClose()\">×</div>\n" +
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" \t\t\t\t\t\t\t</div>\n" +
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"\t\t\t\t\t </div>\n" +
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"\t\t\t\t\t <button type=\"submit\" class=\"btn btn-default\">Submit</button>\n" +
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"\t\t\t\t\t <!-- 显示查询信息的div -->\n" +
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"\t\t\t\t\t <div id=\"completeShow\" style=\"position:absolute;z-index:998;width:200px;\">\n" +
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"\t\t\t\t\t \t<ul id='itemul' class='list-group'>\n" +
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"\t\t\t\t\t \t\t<!--\n" +
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"\t\t\t\t\t \t\t<li class='list-group-item'><a href='#'>查询结果1</a></li>\n" +
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"\t\t\t\t\t \t\t<li class='list-group-item'><a href='#'>查询结果2</a></li>\n" +
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"\t\t\t\t\t \t\t<li class='list-group-item'><a href='#'>查询结果3</a></li>\n" +
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"\t\t\t\t\t \t\t<li class='list-group-item'><a href='#'>查询结果4</a></li>\n" +
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"\t\t\t\t\t \t\t<li class='list-group-item'><a href='#'>查询结果5</a></li>\n" +
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"\t\t\t\t\t \t\t-->\n" +
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"\t\t\t\t\t \t</ul>\n" +
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"\t\t\t\t\t </div>\n" +
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"\t\t\t\t\t </form>\n" +
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"\t\t\t\t\t </div>\n" +
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"\t\t\t\t\t </div>\n" +
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"\t\t\t\t\t</nav>\n" +
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"\t\t\t\t</div>\n" +
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"\t\t\t\t\n" +
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"\t\t\t</div>\n" +
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"\t\t</div>\n" +
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"\t\t\n"
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"</html>");
1，2 概述及格式
JSP是Java独有，比HTML更强大。重要:JSP本质是一个Servlet
除了可以展示HTML效果，还可以嵌入Java代码进行编程
IDEA源码中，可以看到JSP独有内容（包括java代码）
浏览器源码中，看不到JSP独有内容，只能看到htm+css+js
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<%@ page contentType="text/html;charset=UTF-8" language="java" %>
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<html>
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<head>
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<title>Title</title>
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</head>
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<body>
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<%
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int a = 10;
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a+=20;
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%>
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<h1>你好<%out.write(""+a);%></h1>
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</body>
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</html>
小结：
JSP可以编写java代码，html不行。
1，3 课堂案例
课堂案例：JSP编写九九乘法表
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<%@ page contentType="text/html;charset=UTF-8" language="java" %>
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<html>
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<head>
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<title>Title</title>
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</head>
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<body>
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<h1>九九乘法表</h1>
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<%
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//外层控制行
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for (int i = 1; i <=9 ; i++) {
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//内层控制列
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for (int j = 1; j <=i ; j++) {
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out.write(j+"*"+i+"="+(j*i)+" ");
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}
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out.write("<br/>");
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}
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%>
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</body>
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</html>
1，4 JSP作用域回显
JSP展示作用域数据案例：
Servlet
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//需求：访问run2，向request作用域传递 username=小李,请求转发到demo3.jsp
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//demo3.jsp上进行username信息回显
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public String run2(){
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getRequest().setAttribute("username","小李");
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return "forward:/demo3.jsp";
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}
JSP：
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<%@ page contentType="text/html;charset=UTF-8" language="java" %>
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<html>
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<head>
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<title>Title</title>
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</head>
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<body>
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<%-- 相当于：out.write(getRequest().getAttribute("username")) --%>
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<h1>${username}</h1>
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<%-- 获取不到该键值对，返回空字符串 --%>
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<h1>${xxxx}</h1>
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</body>
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</html>
Servlet：getRequest().setAttribute("key","value");
请求转发到JSP
JSP：${key}
如果获取不到该键值对，JSP表达式，返回空字符串
1，5 JSP导包及集合回显
JSP导包和集合数据回显：
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<%@ page contentType="text/html;charset=UTF-8" language="java"
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import="java.util.List,java.util.Map,com.czxy.demo1.domain.Person"%>
<%@ page import="包1,包2"%>
Demo1Servlet:
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//需求：访问run4，向request作用域传递 List<Person>数据，请求转发到demo4.jsp
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//demo4.jsp上进行List<Person>数据回显
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public String run4(){
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List<Person> plist = new ArrayList<>();
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Collections.addAll(plist,
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new Person("007","坤哥","20"),
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new Person("008","隆哥","20"),
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new Person("009","骄姐","18")
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);
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getRequest().setAttribute("plist",plist);
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return "forward:/demo4.jsp";
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}
Jsp:
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<%@ page import="com.czxy.demo1.domain.Person" %>
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<%@ page import="java.util.List" %>
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<%@ page contentType="text/html;charset=UTF-8" language="java" %>
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<html>
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<head>
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<title>Title</title>
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</head>
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<body>
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${plist}
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<hr/>
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<%
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List<Person> plist = (List<Person>) request.getAttribute("plist");
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for (Person p : plist) {
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out.write(p.getId()+","+p.getName()+","+p.getAge()+"<br/>");
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}
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%>
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</body>
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</html>
1，6 案例代码实现
login.jsp
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<form class="form-horizontal" method="post" action="/day04_1/d2">
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<input type="hidden" name="method" value="login"/>
Demo2Servlet
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public String login(){
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boolean result = true;
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String str = "";
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if(result){
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str = "登录成功";
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}else{
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str = "登录失败";
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}
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getRequest().setAttribute("msg",str);
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return "forward:/login.jsp";
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}
login.jsp
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<div class="col-xs-11 col-xs-offset-1">
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<b><font size="4" color="#2B669A">会员登录</font> USER LOGIN</b>
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<br/>
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<b><font size="2" color="red">${msg}</font> </b>
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</div>
最后：
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文章来源: qianxu.blog.csdn.net，作者：爱吃豆的土豆，版权归原作者所有，如需转载，请联系作者。
原文链接：qianxu.blog.csdn.net/article/details/125010119
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