整体的目录结构
我们从上向下依次写代码
controller（Servlet文件）
package com.sz.controller;
import java.io.IOException;
import java.io.PrintWriter;
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 com.sz.entity.User;
import com.sz.service.UserService;
import com.sz.service.Impl.UserServiceImpl;
/**
* 向用户中添加信息，注册
*/
/**
* Servlet implementation class UserSaveController
*/
@WebServlet("/UserSaveController")
public class UserSaveController extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public UserSaveController() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置编码集
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html");
String name = request.getParameter("uname");
int age = Integer.parseInt(request.getParameter("age"));
String birth = request.getParameter("birth");
double salary = Double.parseDouble(request.getParameter("salary"));
UserService service = new UserServiceImpl();
//创建输出流
PrintWriter pw = response.getWriter();
User u = new User(0,name,age,birth,salary);
if(service.saveUser(u)) {//成功
pw.print("<h1>用户注册成功</h1>");
}else {//失败
pw.print("<h1>用户注册失败</h1>");
}
pw.flush();
pw.close();
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
dao包（.class文件）
package com.sz.dao;
import com.sz.entity.User;
import com.sz.util.JDBCUtil;
/**
* 数据访问层
* @author 樊**
*
*/
public class UserDAO {
public int insertUser(User user) {
String sql = "insert into t_stu values(default,'"+user.getUname()+"','"+user.getAge()+"','"+user.getBirth()+"','"+user.getSalary()+"')";
return JDBCUtil.executeSQL(sql);
}
}
entity包（.class文件）
package com.sz.entity;
public class User {
private int id;
private String uname;
private int age;
private String birth;
private double salary;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUname() {
return uname;
}
public void setUname(String uname) {
this.uname = uname;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getBirth() {
return birth;
}
public void setBirth(String birth) {
this.birth = birth;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
public User(int id, String uname, int age, String birth, double salary) {
super();
this.id = id;
this.uname = uname;
this.age = age;
this.birth = birth;
this.salary = salary;
}
public User() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "User [id=" + id + ", uname=" + uname + ", age=" + age + ", birth=" + birth + ", salary=" + salary + "]";
}
}
service下的Impl包中的UserServiceImpl（.class）
package com.sz.service.Impl;
import com.sz.dao.UserDAO;
import com.sz.entity.User;
import com.sz.service.UserService;
public class UserServiceImpl implements UserService{
private UserDAO dao = new UserDAO();
@Override
public boolean saveUser(User user) {
if(dao.insertUser(user) > 0) {
return true;
} else {
return false;
}
}
}
标service包下的UserService(接口)
package com.sz.service;
import com.sz.entity.User;
public interface UserService {
public boolean saveUser(User user);
}
util包
package com.sz.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
* 操作数据库的工具类
* @author 樊**
*
*/
public class JDBCUtil {
private static final String DB_USER_NAME = "root";//数据库的用户名
private static final String DB_PASSWORD ="root";//数据库密码
private static final String DB_NAME = "student";//数据库名称
private static final String IP = "127.0.0.1";//127.0.0.1安装mysql数据库的服务器的ip地址
private static final String URL="jdbc:mysql://"+IP+":3306/"+DB_NAME;//mysql连接地址
//private static final String URL = "jdbc:mysql://"+IP+":3306/"+DB_NAME+"?serverTimezone=UTC";//mysql连接地址
private static Connection conn;//创建连接对象
private static Statement stmt;//执行sql语句的对象，执行命令的对象
private static ResultSet rs;//保存select之后查询结果的数据的对象
/**
* 获得连接对象
* @return
* @throws ClassNotFoundException
* @throws SQLException
*/
private static Connection getCon() throws ClassNotFoundException, SQLException{
//加载mysql驱动
//Class.forName("com.mysql.cj.jdbc.Driver");
Class.forName("com.mysql.jdbc.Driver");
if(conn == null || conn.isClosed()){//防止多次赋值
conn = DriverManager.getConnection(URL, DB_USER_NAME, DB_PASSWORD);
}
return conn;
}
/**
* 获得Statement对象，用于执行sql语句
* @return
* @throws ClassNotFoundException
* @throws SQLException
*/
private static Statement openStmt() throws ClassNotFoundException, SQLException{
stmt = getCon().createStatement();
return stmt;
}
/**
* 执行数据库的增(insert)、删(delete)、改(update)的操作
* @param sql
* @return
*/
public static int executeSQL(String sql){
int i = 0;
try {
i = openStmt().executeUpdate(sql);//执行sql语句
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally{
//关闭数据库相关对象
close();
}
return i;
}
/**
* 执行数据库查询（select）的操作
* @param sql
* @return
*/
public static ResultSet search(String sql){
try {
rs = openStmt().executeQuery(sql);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return rs;
}
/**
* 关闭数据库的方法
*/
public static void close(){
try {
if(rs != null){
rs.close();//关闭ResultSet，顺序很重要不要错
}
if(stmt != null){
stmt.close();//关闭Statement
}
if(conn != null){
conn.close();//关闭Connection对象
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
regedit.jsp（编码集都是UTF-8 记得改要不然全是乱码）
<%@ 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>
<form action="UserSaveController" method="get">
用户名：<input name="uname" type="text" size="12"/><br/>
年龄：<input name="age" type="text" size="12"/><br/>
生日：<input name="birth" type="text" size="12"/><br/>
工资：<input name="salary" type="text" size="12"/><br/>
<input type="submit" value="注册"/>
<input type="reset" value="重置"/>
</form>
</body>
</html>
数据库中的结构如下：
注意：要记得的改项目的编码集为utf-8。
下面开始测试：
浏览器中输入如下网址：http://127.0.0.1:8080/20210911/regrdit.jsp会出现如下页面。
然后输入信息入下。
点击注册。跳转到如下界面。
然后返回到你的数据库，刷新数据库。会看到刚才注册的信息出现到了数据库中。
至此，恭喜你已经完成了MVC四层架构的用户注册模式。说说我自己的感受吧，第一次接触四层架构的时候比较绕，绕来绕去的，想在网上找资料，结果发现全都是付费的，这对于我这个穷人来讲实在是太难受了，所以索性自己跟老师学会了，自己发布一个博客，方便我后期自己学习。