MVC是什么?
MVC,全称model view controller—模型，视图，控制器
model是将数据库中的表到Java中变成实体类
view是编写JSP页面
controller是用来业务逻辑的处理
MVC框架实现登录注册功能
项目框架结构
工具类Util
package com.ishopn.util;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.List;public class DBHelper {private static String url="jdbc:mysql://localhost:3306/ishopn?characterEncoding=utf8";private static String user = "root";private static String password = "1234";/*** 统一的获取数据库连接对象的方法* @param url 数据库连接路径* @param user 用户名* @param password 密码* @return 数据库连接对象*/public static Connection getConnection() {Connection conn = null;try {Class.forName("com.mysql.jdbc.Driver");conn = DriverManager.getConnection(url, user, password);} catch (Exception e) {e.printStackTrace();}return conn;}/*** 统一的关闭数据库连接方法* @param conn 数据库的连接对象*/public static void closeConnection(Connection conn) {if(conn!=null) {try {conn.close();} catch (SQLException e) {e.printStackTrace();}}}/*** 统一的sql查询方法* @param conn 连接对象* @param sql需要执行的sql语句* @param paramsql语句中需要替换的参数列表* @return ResultSet 资源结果集*/public static ResultSet execteQuery(Connection conn,String sql,List param) {ResultSet rs = null;try {PreparedStatement ps = conn.prepareStatement(sql);if(param!=null && param.size()>0) {for(int i=0;i<param.size();i++) {ps.setObject(i+1, param.get(i));}}rs = ps.executeQuery();} catch (Exception e) {e.printStackTrace();}return rs;}/*** 统一的sql语句更新方法* @param conn 连接对象* @param sql 需要执行的sql语句* @param param sql语句中需要替换的参数列表* @return 受影响行数*/public static int executeUpdate(Connection conn,String sql,List param) {int line = 0;try {PreparedStatement ps = conn.prepareStatement(sql);if(param!=null && param.size()>0) {for(int i=0;i<param.size();i++) {ps.setObject(i+1, param.get(i));}}line = ps.executeUpdate();}catch(Exception e) {e.printStackTrace();}return line;}}
dao层的实现类
package com.ishopn.dao.impl;import java.sql.Connection;import java.sql.ResultSet;import java.util.ArrayList;import java.util.List;import com.ishopn.dao.CustomerDao;import com.ishopn.model.Customer;import com.ishopn.util.DBHelper;public class CustomerDaoimpl implements CustomerDao{@Override//该方法用来验证用户的名称和手机号是否正确public int getcountCustmerByNameAndPhone(Customer cu) {int count = 0;try {//连接数据库 通过DBHelper类中的方法Connection conn = DBHelper.getConnection();String sql = "select count(*) from customer where cu_name=? and cu_phone=?";//将Controller层从页面中获取的参数添加到集合中List param = new ArrayList();param.add(cu.getCu_name());param.add(cu.getCu_phone());//调用DBHelper中的execteQuery方法 获得资源结果集ResultSet rs = DBHelper.execteQuery(conn, sql, param);rs.next();count = rs.getInt(1);//关闭数据库连接DBHelper.closeConnection(conn);}catch(Exception e) {e.printStackTrace();}return count;}//这个方法用来更新数据库的数据 例如实现用户注册功能@Overridepublic int istCustomer(Customer cu) {int line = 0; //line为数据库中 受影响的行数try {//连接数据库Connection conn = DBHelper.getConnection();String sql = "insert into customer (cu_id,cu_name,cu_phone,cu_gender,cu_address) values (?,?,?,?,?)";List param = new ArrayList();//将Controller层传入的数据保存到集合中 并调用数据库param.add(cu.getCu_id());param.add(cu.getCu_name());param.add(cu.getCu_phone());param.add(cu.getCu_gender());param.add(cu.getCu_address());line = DBHelper.executeUpdate(conn, sql, param);//关闭数据库连接DBHelper.closeConnection(conn);}catch(Exception e) {e.printStackTrace();}return line;}}
Controller层 业务逻辑处理
package com.ishopn.controller;import com.ishopn.dao.CustomerDao;import com.ishopn.dao.impl.CustomerDaoimpl;import com.ishopn.model.Customer;public class CustomerController {private CustomerDao customerDao;//这个类中需要用到Dao层的实现类，因此在构造方法里面实例化Dao对象public CustomerController() {customerDao = new CustomerDaoimpl();}//此方法将页面中传入的用户名和用户手机号拿到数据库中的数据进行select查询public int getcountCustmerByNameAndPhone(String cu_name,String cu_phone) {Customer cu = new Customer(); //实例化一个用户，将页面中的参数保存cu.setCu_name(cu_name);cu.setCu_phone(cu_phone);//调用Dao层方法，取链接数据库并查询是否存在该用户return customerDao.getcountCustmerByNameAndPhone(cu);}//该方法用于用户的注册public int istCustomer(String cu_id,String cu_name,String cu_phone,Integer cu_gender,String cu_address) {//实例化用户对象，将用户的注册信息保存到用户对象中Customer cu = new Customer();cu.setCu_id(cu_id);cu.setCu_name(cu_name);cu.setCu_phone(cu_phone);cu.setCu_gender(cu_gender);cu.setCu_address(cu_address);//调用Dao层去连接并更新数据库 返回受影响行数return customerDao.istCustomer(cu);}}
Servlet层
//登录的Servlet//登录的Servletpackage com.ishopn.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import com.ishopn.controller.CustomerController;public class LoginServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("utf-8");resp.setCharacterEncoding("utf-8");//获取页面中的用户名和用户手机号String cu_name = req.getParameter("cu_name");String cu_phone = req.getParameter("cu_phone");//实例化Controller层对象CustomerController cc = new CustomerController();//调用Controller层对象的方法 判断输入的用户名和手机号是否存在数据库中int count = cc.getcountCustmerByNameAndPhone(cu_name, cu_phone);if(count>0) {//假如存在该用户，则设置Cookie和session 并进行页面的跳转Cookie cookie = new Cookie("cu_name",cu_name);resp.addCookie(cookie);HttpSession session = req.getSession();session.setAttribute("cu_name", cu_name);resp.sendRedirect("/web06/welcome.jsp");}else {resp.sendRedirect("/web06");}}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doGet(req,resp);}}
//注册的Servlet//注册的Servletpackage com.ishopn.servlet;import java.io.IOException;import java.util.UUID;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.ishopn.controller.CustomerController;//将普通类继承HttpServlet变成Servletpublic class RegistServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("utf-8");resp.setCharacterEncoding("utf-8");//与登录一样，获取用户在页面输入的信息String cu_id = UUID.randomUUID().toString();String cu_name = req.getParameter("cu_name");String cu_phone = req.getParameter("cu_phone");Integer cu_gender = new Integer(req.getParameter("cu_gender"));String cu_address = req.getParameter("cu_address");//实例化Controller层对象 并调用注册方法CustomerController cc = new CustomerController();//该方法返回一个受影响行数 ，假如行数大于1，说明数据在数据库中插入成功int line = cc.istCustomer(cu_id, cu_name, cu_phone, cu_gender, cu_address);//System.out.println("我要跳转了！！！！");if(line > 0) {//受影响行数大于1 则注册成功 页面惊醒跳转resp.sendRedirect("/web06");}}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doGet(req,resp);}}
