一、使用web.xml文件设置网页首选项

第一步：首先在新建项目时，先莫着急点击finish，咱应该先点next
第二步：再点next
第三步：选择勾选 Generate web.xml deployment descriptor，最后就再点击finish
注意：在设置完网页首选项之后，一定要重启服务

二、jsp的基本标签

1、 jsp的常用标签：

2、useBean的用法

3、 setProperty的用法

三、代码部分

用户类 User.java：

package com.zking.pojo;
 
public class User {
	
	private Integer userid;
	private String username;
	private String password;
	public Integer getUserid() {
		return userid;
	}
	public void setUserid(Integer userid) {
		this.userid = userid;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public User(Integer userid, String username, String password) {
		super();
		this.userid = userid;
		this.username = username;
		this.password = password;
	}
	
	public User() {
		// TODO Auto-generated constructor stub
	}
	@Override
	public String toString() {
		return "User [userid=" + userid + ", username=" + username + ", password=" + password + "]";
	}
	
	
	
	
 
}

登录页面 login.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>欢迎登陆</h1>
<!-- 
	//	type:
	//		1.热门商品
	//		2.折扣商品
	// 		3.人气商品
 -->
<jsp:include page="index.jsp">
	<jsp:param value="1" name="type"/>
</jsp:include>
<jsp:include page="index.jsp">
	<jsp:param value="2" name="type"/>
</jsp:include>
<jsp:include page="index.jsp">
	<jsp:param value="3" name="type"/>
</jsp:include>
 
<%--
<jsp:forward page="index.jsp"/ > 
--%> 
 
<%--<!-- --> 是html注释	会执行	这个是java注释--%>
 
<form action="doLogin.jsp">
	<input name="userid"><br>
	<input name="username"><br>
	<input name="password"><br>
	<button>登录</button>
	
 
</form>
 
</body>
</html>

做登录页面 doLogin.jsp：

<%@page import="com.zking.pojo.User"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%
	User user=new User();
	user.setUserid(1);
	user.getUserid();
	
	
%>
<!-- User u=new User(); -->
<jsp:useBean id="u" class="com.zking.pojo.User"></jsp:useBean>
 
<!-- property 属性 -->
<!-- u.setUsername("haha"); -->
<jsp:setProperty property="userid" name="u" param="userid"/>
<jsp:setProperty property="username" name="u" param="username"/>
<jsp:setProperty property="password" name="u" param="password" />
 
<!-- u.getUsername("haha"); -->
<jsp:getProperty property="username" name="u" />
 
 
<%
	u.getUserid();
	out.print(u);
 
%>

主页 index.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
	<style>
		.h1{
			border:10px solid pink;
			height:200px;
		}
	</style>
</head>
<body>
<%
	String type=request.getParameter("type");
 
	//根据别人携带的参数做判断
	
	//	type:
	//		1.热门商品
	//		2.折扣商品
	// 		3.人气商品
	
	String data="";
	
	if("1".equals(type)){
		data="热门商品";
	}
 
	if("2".equals(type)){
		data="折扣商品";
	}
 
	if("3".equals(type)){
		data="人气商品";
	}
%>
<h1 class="h1"><%=data %></h1>
</body>
</html>