一、Servlet+JSP+JavaBean开发模式(MVC)介绍
Servlet+JSP+JavaBean模式(MVC)适合开发复杂的web应用，在这种模式下，servlet负责处理用户请求，jsp负责数据显示，javabean负责封装数据。 Servlet+JSP+JavaBean模式程序各个模块之间层次清晰，web开发推荐采用此种模式。
这里以一个最常用的用户登录注册程序来讲解Servlet+JSP+JavaBean开发模式，通过这个用户登录注册程序综合案例，把之前的学过的XML、Xpath、Servlet、jsp的知识点都串联起来。
二、创建MVC架构的Web项目
在MyEclipse中新创建一个webmvcframework项目，导入项目所需要的开发包(jar包)，创建项目所需要的包，在java开发中，架构的层次是以包的形式体现出来的
项目所需要的开发包(jar包)
序号
开发包名称
描述
1
dom4j-1.6.1.jar
dom4j用于操作XML文件
2
jaxen-1.1-beta-6.jar
用于解析XPath表达式
3
commons-beanutils-1.8.0.jar
工具类，用于处理bean对象
4
commons-logging.jar
commons-beanutils-1.8.0.jar的依赖jar包
5
jstl.jar
jstl标签库和EL表达式依赖包
6
standard.jar
jstl标签库和EL表达式依赖包
一个良好的JavaWeb项目架构应该具有以上的11个包，这样显得层次分明，各个层之间的职责也很清晰明了，搭建JavaWeb项目架构时，就按照上面的1~11的序号顺序创建包：domain→dao→dao.impl→service→service.impl→web.controller→web.UI→web.filter→web.listener→util→junit.test，包的层次创建好了，项目的架构也就定下来了，当然，在实际的项目开发中，也不一定是完完全全按照
项目所需要的包
序号
包名
描述
所属层次
1
me.gacl.domain
存放系统的JavaBean类(只包含简单的属性以及属性对应的get和set方法，不包含具体的业务处理方法)，提供给【数据访问层】、【业务处理层】、【Web层】来使用
domain(域模型)层
2
me.gacl.dao
存放访问数据库的操作接口类
数据访问层
3
me.gacl.dao.impl
存放访问数据库的操作接口的实现类
4
me.gacl.service
存放处理系统业务接口类
业务处理层
5
me.gacl.service.impl
存放处理系统业务接口的实现类
6
me.gacl.web.controller
存放作为系统控制器的Servlet
Web层(表现层)
7
me.gacl.web.UI
存放为用户提供用户界面的servlet(UI指的是user interface)
8
me.gacl.web.filter
存放系统的用到的过滤器(Filter)
9
me.gacl.web.listener
存放系统的用到的监听器(Listener)
10
me.gacl.util
存放系统的通用工具类，提供给【数据访问层】、【业务处理层】、【Web层】来使用
11
junit.test
存放系统的测试类
上面说的来创建包的层次结构，而是根据项目的实际情况，可能还需要创建其他的包，这个得根据项目的需要来定了
在src目录(类目录)下面，创建用于保存用户数据的xml文件(DB.xml)
在WEB-INF目录下创建一个pages目录，pages目录存放系统的一些受保护(不允许用户直接通过URL地址访问)的jsp页面，用户要想访问这些受保护的jsp页面，那么只能通过me.gacl.web.UI这个包里面的Servlet
三、分层架构的代码编写
分层架构的代码也是按照【域模型层(domain)】→【数据访问层(dao、dao.impl)】→【业务处理层(service、service.impl)】→【表现层(web.controller、web.UI、web.filter、web.listener)】→【工具类(util)】→【测试类(junit.test)】的顺序进行编写的。
一：首先我们因为要查询到数据 应该先建立我们需要的数据库
#判断存在即删除数据库
drop database if exists mydb;
#创建数据库
create database mydb;
#使用数据库
use mydb;
#创建表
create table t_user
(
uid int primary key auto_increment,
username varchar(20),
password varchar(20),
phone varchar(11),
address varchar(50)
);
insert into t_user(username,password,phone,address) values('张三','666','18965423548','南阳');
insert into t_user(username,password,phone,address) values('李四','333','18754263548','许昌');
insert into t_user(username,password,phone,address) values('小美','123','18565234759','信阳');
select * from t_user where username=? and password=?
select * from t_user;
create table t_goods
(
gid int primary key auto_increment,
gname varchar(20),
price double,
mark varchar(100)
);
insert into t_goods(gname,price,mark) values('泡面',4.5,'够香够辣就是这个味！');
insert into t_goods(gname,price,mark) values('火腿',8.5,'肉质细腻Q弹！');
insert into t_goods(gname,price,mark) values('雪碧',3.5,'清爽冰凉随心爽！');
select * from t_goods;
二：准备我们的登录页面jsp代码
1：首页
<%--
Created by IntelliJ IDEA.
User: 大大怪将军
Date: 2023/2/14
Time: 10:52
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>这是第一次JavaWeb项目</title>
</head>
<body>
<h2>这是第一次文本</h2>
<a href="login.jsp" >去登录</a>
<a href="zhuce.jsp" >注册</a>
</body>
</html>
2:登录页面
<%--
Created by IntelliJ IDEA.
User: 大大怪将军
Date: 2023/2/14
Time: 11:06
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title></title>
</head>
<body>
<form action="dl" method="post">
账号:<input type="text" name="username" value=""><br>
密码:<input type="password" name="password" value=""><br>
<input type="submit" value="登录">
</form>
</body>
</html>
3：登录过后的主页内容显示
<%--
Created by IntelliJ IDEA.
User: 大大怪将军
Date: 2023/2/16
Time: 12:20
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>主页</title>
</head>
<body>
<h2>欢迎来到javaweb项目</h2>
<table>
<thead>
<tr>
<th>编号</th>
<th>名称</th>
<th>价格</th>
<th>说明</th>
</tr>
</thead>
<tbody>
<tr>
<td>泡面</td>
<td>4.5</td>
<td>够香够辣就是这个味！</td>
</tr>
<tr>
<td>火腿</td>
<td>8.5</td>
<td>肉质细腻Q弹！</td>
</tr><tr>
<td>雪碧</td>
<td>3.5</td>
<td>清爽冰凉随心爽！</td>
</tr>
</tbody>
</table>
</body>
</html>
4：准备servlet映射
<?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>login</servlet-name>
<servlet-class>com.huanxiao.servlet.Login</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>aa</servlet-name>
<servlet-class>com.huanxiao.servlet.Login</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>aa</servlet-name>
<url-pattern>/dl</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>zhuce</servlet-name>
<servlet-class>com.huanxiao.servlet.ZhuCe</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>zhuce</servlet-name>
<url-pattern>/zhuce</url-pattern>
</servlet-mapping>
</web-app>5：准备我们的实体类 （User类 和Goods类）起名和数据库的名字起的一样方便
package com.huanxiao.bean;
public class Goods {
private Integer gid;
private String gname;
private Double price;
private String mark;
public Integer getGid() {
return gid;
}
public void setGid(Integer gid) {
this.gid = gid;
}
public String getGname() {
return gname;
}
public void setGname(String gname) {
this.gname = gname;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public String getMark() {
return mark;
}
public void setMark(String mark) {
this.mark = mark;
}
@Override
public String toString() {
return "Goods{" +
"gid=" + gid +
", gname='" + gname + '\'' +
", price=" + price +
", mark='" + mark + '\'' +
'}';
}
}
package com.huanxiao.bean;
public class User {
private Integer uid;
private String username;
private String password;
private String phone;
private String address;
public Integer getUid() {
return uid;
}
public void setUid(Integer uid) {
this.uid = uid;
}
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 String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User{" +
"uid=" + uid +
", username='" + username + '\'' +
", password='" + password + '\'' +
", phone='" + phone + '\'' +
", address='" + address + '\'' +
'}';
}
}
7：登录失败后显示的页面
<%--
Created by IntelliJ IDEA.
User: 大大怪将军
Date: 2023/2/16
Time: 12:07
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>错误页面</title>
</head>
<body>
<a href="login.jsp">重新登录</a>
</body>
</html>
8：准备我们的java登录代码操作
package com.huanxiao.servlet;
import com.huanxiao.bean.User;
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.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class Login extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("Login...Get");
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//这三个都是获取请求的地址相关
// String uri=request.getRequestURI();
// String contextPath = request.getContextPath();
// String servletPath = request.getServletPath();
//
// System.out.println(uri);//包含项目名和资源名
// System.out.println(contextPath);//项目名称
// System.out.println(servletPath);//请求的资源路径
//1:从请求中获取用户提交写参数(数据)
request.setCharacterEncoding("utf-8");//设置请求的编码格式为中文
String username = request.getParameter("username");
String password = request.getParameter("password");
// System.out.println(username);
// System.out.println(password);
Connection connection=null;
PreparedStatement pstm=null;
ResultSet rs=null;
User login=null;
try {
Class.forName("com.mysql.cj.jdbc.Driver");
connection= DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb?useSSL=false&serverTimezone=UTC","root","123456");
String sql="select * from t_user where username=? and password=?";
pstm= connection.prepareStatement(sql);
pstm.setObject(1,username);
pstm.setObject(2,password);
rs= pstm.executeQuery();
if(rs.next()){
login=new User();
login.setUid(rs.getInt("uid"));
login.setUsername(rs.getString("username"));
login.setPassword(rs.getString("password"));
login.setPhone(rs.getString("phone"));
login.setAddress(rs.getString("address"));
}
}catch (Exception e){
e.printStackTrace();
}finally {
try {
if(rs!=null){
rs.close();
}
if(pstm!=null){
pstm.close();
}
if(connection!=null){
connection.close();
}
}catch (Exception e){
e.printStackTrace();
}
}
response.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=UTF-8");
if(login!=null){
response.sendRedirect("zhuye.jsp");
}else{
response.sendRedirect("erroir.jsp");
}
}
}
三：注册页面jsp代码
1：主页注册代码
<%--
Created by IntelliJ IDEA.
User: 大大怪将军
Date: 2023/2/14
Time: 10:52
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>这是第一次JavaWeb项目</title>
</head>
<body>
<h2>这是第一次文本</h2>
<a href="login.jsp" >去登录</a>
<a href="zhuce.jsp" >注册</a>
</body>
</html>
2：跳转到注册页面
<%--
Created by IntelliJ IDEA.
User: 大大怪将军
Date: 2023/2/14
Time: 11:14
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>注册</title>
</head>
<body>
<form action="zhuce" method="post">
请输入你的姓名:<input type="text" name="username" value=""><br>
请输入你的密码:<input type="password" name="password" value=""><br>
请输入你的手机号:<input type="text" name="phone" value=""><br>
请输入你的地址:<input type="text" name="address" value=""><br>
<input type="submit" value="注册">
</form>
</body>
</html>
3：准备servlet映射
<?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>login</servlet-name>
<servlet-class>com.huanxiao.servlet.Login</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>aa</servlet-name>
<servlet-class>com.huanxiao.servlet.Login</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>aa</servlet-name>
<url-pattern>/dl</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>zhuce</servlet-name>
<servlet-class>com.huanxiao.servlet.ZhuCe</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>zhuce</servlet-name>
<url-pattern>/zhuce</url-pattern>
</servlet-mapping>
</web-app>4：注册页面java代码操作
package com.huanxiao.servlet;
import com.huanxiao.bean.User;
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.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class ZhuCe extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");//设置请求的编码格式为中文
String username = request.getParameter("username");
String password = request.getParameter("password");
String phone = request.getParameter("phone");
String address = request.getParameter("address");
// System.out.println(username);
// System.out.println(password);
try {
Boolean zhucetext = zhucetext(username, password, phone, address);
response.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=UTF-8");
if(zhucetext){
response.getWriter().write("<h1>注册成功</h1>");
} else {
response.getWriter().write("<h1>注册失败</h1>");
}
} catch (Exception e) {
e.printStackTrace();
}
}
public Boolean zhucetext(String username, String password, String phone, String address) throws Exception {
Class.forName("com.mysql.cj.jdbc.Driver");
Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb?useSSL=false&serverTimezone=UTC",
"root", "123456");
String sql = "insert into t_user (username,password,phone,address)values (?,?,?,?)";
PreparedStatement pstm = connection.prepareStatement(sql);
pstm.setObject(1, username);
pstm.setObject(2, password);
pstm.setObject(3, phone);
pstm.setObject(4, address);
int i = pstm.executeUpdate();
if (i > 0) {
if (pstm != null) {
pstm.close();
}
if (connection != null) {
connection.close();
}
return true;
} else {
return false;
}
}
}
四：登录页面显示效果
五：注册页面效果显示
分层操作：
一：创建4个包bean（放实体类） dao（放接口和java登录注册代码）servlet（放java调用运行代码）
util（放sql连接语句 关闭资源代码 ）
1：把我们需要的sql语句连接放到我们新创建的JDBCUtil包中
package com.huanxiao.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class JDBCUtil {
private static String dirver="com.mysql.cj.jdbc.Driver";
private static String url="jdbc:mysql://localhost:3306/mydb?useSSL=false&serverTimezone=UTC";
private static String user="root";
private static String password="123456";
private static Connection connection=null;
public static Connection getCon(){
try {
Class.forName(dirver);
connection= DriverManager.getConnection(url,user,password);
}catch (Exception e){
e.printStackTrace();
}
return connection;
}
public static void close( PreparedStatement pstm, Connection connection){
try{
if(pstm!=null){
pstm.close();
}
if(connection!=null){
connection.close();
}
}catch (Exception e){
e.printStackTrace();
}
}
public static void clos(ResultSet rs, PreparedStatement pstm, Connection con){
try{
if(rs!=null){
rs.close();
}
if(pstm!=null){
pstm.close();
}
if(con!=null){
con.close();
}
}catch (Exception e){
e.printStackTrace();
}
}
}
2：创建我们所需要的接口
package com.huanxiao.dao;
import com.huanxiao.bean.User;
public interface UserDao {
public User login(String username, String password);
public int zhuce(User user);
}
3：准备java登录注册代码 开始需要连接接口文章来源：https://www.toymoban.com/news/detail-775243.html
package com.huanxiao.dao.impl;
import com.huanxiao.bean.User;
import com.huanxiao.dao.UserDao;
import com.huanxiao.util.JDBCUtil;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class UserDaoImpl implements UserDao {
Connection connection = null;
PreparedStatement pstm = null;
ResultSet rs = null;
User lo = null;
int row = 0;
@Override
public User login(String username, String password) {
Connection con = null;
PreparedStatement pstm = null;
try {
connection= JDBCUtil.getCon();
String sql = "select * from t_user where username=? and password=?";
pstm = connection.prepareStatement(sql);
pstm.setObject(1, username);
pstm.setObject(2, password);
rs = pstm.executeQuery();
if (rs.next()) {
lo = new User();
lo.setUid(rs.getInt("uid"));
lo.setUsername(rs.getString("username"));
lo.setPassword(rs.getString("password"));
lo.setPhone(rs.getString("phone"));
lo.setAddress(rs.getString("address"));
}
} catch (Exception e) {
e.printStackTrace();
}finally {
JDBCUtil.clos(rs,pstm,connection);
}
return lo;
}
@Override
public int zhuce (User user){
Connection con = null;
PreparedStatement pstm = null;
try {
con = JDBCUtil.getCon();
String sql = "insert into t_user(username,password,phone,address) values(?,?,?,?);";
pstm = con.prepareStatement(sql);
pstm.setObject(1, user.getUsername());
pstm.setObject(2, user.getPassword());
pstm.setObject(3, user.getPhone());
pstm.setObject(4, user.getAddress());
row = pstm.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtil.close(pstm, con);
}
return row;
}
}
5：准备java运行代码文章来源地址https://www.toymoban.com/news/detail-775243.html
package com.huanxiao.servlet;
import com.huanxiao.bean.User;
import com.huanxiao.dao.UserDao;
import com.huanxiao.dao.impl.UserDaoImpl;
import com.huanxiao.util.JDBCUtil;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
@WebServlet("/dl")
public class Login extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("Login...Get");
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//这三个都是获取请求的地址相关
// String uri=request.getRequestURI();
// String contextPath = request.getContextPath();
// String servletPath = request.getServletPath();
//
// System.out.println(uri);//包含项目名和资源名
// System.out.println(contextPath);//项目名称
// System.out.println(servletPath);//请求的资源路径
//1:从请求中获取用户提交写参数(数据)
request.setCharacterEncoding("utf-8");//设置请求的编码格式为中文
response.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=UTF-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
// System.out.println(username);
// System.out.println(password);
UserDaoImpl userDao=new UserDaoImpl();
User lo=userDao.login(username,password);
if(lo!=null){
response.sendRedirect("zhuye.jsp");
}else{
response.sendRedirect("erroir.jsp");
}
}
}
package com.huanxiao.servlet;
import com.huanxiao.bean.User;
import com.huanxiao.dao.UserDao;
import com.huanxiao.dao.impl.UserDaoImpl;
import javax.jws.WebService;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/zhuce")
public class Rsgister extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("type/html;charset=utf-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
String phone = request.getParameter("phone");
String address = request.getParameter("address");
User user=new User();
user.setUsername(username);
user.setPassword(password);
user.setPhone(phone);
user.setAddress(address);
UserDao userDao= new UserDaoImpl();
int row=userDao.zhuce(user);
if(row>0){
response.sendRedirect("login.jsp");
}else {
response.sendRedirect("erroir.jsp");
}
}
}
到了这里，关于使用javaweb实现登录注册页面，并且对功能和业务进行分层 用户登录成功跳转到主页并展示数据库的商品的信息的文章就介绍完了。如果您还想了解更多内容，请在右上角搜索TOY模板网以前的文章或继续浏览下面的相关文章，希望大家以后多多支持TOY模板网！
