超市订单管理系统updating

2024-03-05 08:19:54

SMBMS

数据库：

项目搭建准备工作

使用Maven

搭配一个maven web项目
配置Tomcat
测试项目是否能够跑起来
导入项目中会遇到的jar包
jsp, Servlet, mysql驱动, jstl, standard...
创建包结构
编写实体类
ORM映射：表-类映射

编写基础公共类

数据库配置文件

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/smbms?useSSL=true&useUnicode=true&characterEncoding=utf-8
username=root
password=123456

编写数据库公共类

package com.hitenine.dao;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

//操作数据库的公共类
public class BaseDao {

    private static String driver;
    private static String url;
    private static String username;
    private static String password;


    //静态代码块，类加载的时候就初始化了
    static {
        Properties properties = new Properties();
        //通过类加载器读取对应的资源
        InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");

        try {
            properties.load(is);
        } catch (IOException e) {
            e.printStackTrace();
        }

        driver = properties.getProperty("driver");
        url = properties.getProperty("url");
        username = properties.getProperty("username");
        password = properties.getProperty("password");
    }

    //获取数据库的连接
    public static Connection getConnection() {
        Connection connection = null;
        try {
            Class.forName(driver);
            connection = DriverManager.getConnection(url, username, password);
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("ok");
        return connection;
    }

    /*
    有些bug
     */
    //编写查询公共方法
    public static ResultSet execute(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet, String sql, Object[] params) throws SQLException {
        //预编译的sql，在后面直接执行就可以了
        preparedStatement = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++) {
            //setObject，占据符从1开始，但是我们的数组是从0开始的
            preparedStatement.setObject(i + 1, params[i]);
        }

        resultSet = preparedStatement.executeQuery();
        return resultSet;
    }

    //编写增删改公共方法
    public static int execute(Connection connection, PreparedStatement preparedStatement, String sql, Object[] params) throws SQLException {
        //预编译的sql，在后面直接执行就可以了
        preparedStatement = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++) {
            //setObject，占据符从1开始，但是我们的数组是从0开始的
            preparedStatement.setObject(i + 1, params[i]);
        }

        int updateRows = preparedStatement.executeUpdate();
        return updateRows;
    }

    //释放资源
    public static boolean closeResource(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet) {
        boolean flag = true;

        if (null != resultSet) {
            try {
                resultSet.close();
                //GC回收
                resultSet = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        if (null != preparedStatement) {
            try {
                preparedStatement.close();
                //GC回收
                preparedStatement = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        if (null != connection) {
            try {
                connection.close();
                //GC回收
                connection = null;
            } catch (SQLException e) {
                e.printStackTrace();
                flag = false;
            }
        }
        return flag;
    }


}

编写字符编码过滤器

导入静态资源

登录功能实现

编写前端页面

设置首页

<!--设置首页-->
<welcome-file-list>
    <welcome-file>login.jsp</welcome-file>
</welcome-file-list>

编写dao层登录用户登录的接口

//得到要登录的用户
public User getLoginUser(Connection connection, String userCode) throws SQLException;

编写dao接口的实现类

package com.hitenine.dao.user;

import com.hitenine.dao.BaseDao;
import com.hitenine.pojo.User;

import javax.servlet.http.HttpServlet;
import java.sql.*;

public class UserDaoImpl  extends HttpServlet implements UserDao{

    //得到要登录的用户
    @Override
    public User getLoginUser(Connection connection, String userCode) throws SQLException {
        PreparedStatement pstm = null;
        ResultSet rs = null;
        User user = null;

        if (null != connection) {
            String sql = "select * from smbms_user where userCode=?";
            Object[] params = {userCode};

            Statement statement = connection.createStatement();


            rs = BaseDao.execute(connection, pstm, rs, sql, params);

            if (rs.next()) {
                user = new User();
                user.setId(rs.getInt("id"));
                user.setUserCode(rs.getString("userCode"));
                user.setUserName(rs.getString("userName"));
                user.setUserPassword(rs.getString("userPassword"));
                user.setGender(rs.getInt("gender"));
                user.setBirthday(rs.getDate("birthday"));
                user.setPhone(rs.getString("phone"));
                user.setAddress(rs.getString("address"));
                user.setUserRole(rs.getInt("userRole"));
                user.setCreatedBy(rs.getInt("createdBy"));
                user.setCreationDate(rs.getTimestamp("creationDate"));
                user.setModifyBy(rs.getInt("modifyBy"));
                user.setModifyDate(rs.getTimestamp("modifyDate"));
            }
            BaseDao.closeResource(null, pstm, rs);
        }

        return user;
    }

}

业务层接口

//用户登录
public User login(String userCode, String password);

业务层实现类

package com.hitenine.service.user;

import com.hitenine.dao.BaseDao;
import com.hitenine.dao.user.UserDao;
import com.hitenine.dao.user.UserDaoImpl;
import com.hitenine.pojo.User;

import java.sql.Connection;
import java.sql.SQLException;

public class UserServiceImpl implements UserService {

    //业务层都会调用dao层，所以我们要引入Dao层
    private UserDao userDao;
    public UserServiceImpl() {
        userDao = new UserDaoImpl();
    }

    @Override
    public User login(String userCode, String password) {
        Connection connection = null;
        User user = null;

        try {
            connection = BaseDao.getConnection();
            //通过业务层调用对应的数据库操作
            user = userDao.getLoginUser(connection, userCode);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            BaseDao.closeResource(connection, null, null);
        }

        return user;
    }

编写Servlet

package com.hitenine.servlet.user;

import com.hitenine.pojo.User;
import com.hitenine.service.user.UserServiceImpl;
import com.hitenine.util.Constants;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LoginServlet extends HttpServlet {

    //Servlet:控制层，调用业务层

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        System.out.println("LoginServlet---start---");

        //获取用户名和密码
        String userCode = req.getParameter("userCode");
        String userPassword = req.getParameter("userPassword");

        //和数据库中的密码进行对比，调用业务层
        UserServiceImpl userService = new UserServiceImpl();
        User user = userService.login(userCode, userPassword); //这里已经把登录的人给查出来了

        //判断语句加上user.getUserPassword().equals(userPassword)，为了便于测试暂不加
        if (null != user) { //查有此人，可以登录
            //将用户的信息放到Session中
            req.getSession().setAttribute(Constants.USER_SESSION, user);

            //跳转到内部主页
            resp.sendRedirect("jsp/frame.jsp");
        } else { //查无此人，无法登录
            //转发会登陆页面，顺带提示用户名或者密码错误
            req.setAttribute("error", "用户名或者密码不正确");
            req.getRequestDispatcher("login.jsp").forward(req, resp);
        }

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

注册Servlet

<!--Servlet-->
<servlet>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>com.hitenine.servlet.user.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/login.do</url-pattern>
</servlet-mapping>

测试访问，确保以上功能成功！

登录功能优化

注销功能

思路：移除Session，返回登陆页面

package com.hitenine.servlet.user;

import com.hitenine.util.Constants;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LogoutServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //移除用户的Constants.USER_SESSION
        req.getSession().removeAttribute(Constants.USER_SESSION);
        resp.sendRedirect(req.getContextPath() + "/login.jsp"); //返回登录页面
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

注册xml

<servlet>
    <servlet-name>LogoutServlet</servlet-name>
    <servlet-class>com.hitenine.servlet.user.LogoutServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>LogoutServlet</servlet-name>
    <url-pattern>/jsp/logout.do</url-pattern>
</servlet-mapping>

登录拦截优化

package com.hitenine.filter;

import com.hitenine.pojo.User;
import com.hitenine.util.Constants;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class SysFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse resp = (HttpServletResponse) response;

        User user = (User) req.getSession().getAttribute(Constants.USER_SESSION);

        if (null == user) { //已经被移除或者注销了，或者未登录
            resp.sendRedirect("/smbms/error.jsp");
        } else {
            chain.doFilter(request, response);
        }

    }

    @Override
    public void destroy() {

    }
}

注册xml

<!--用户登录过滤器-->
<filter>
    <filter-name>SysFilter</filter-name>
    <filter-class>com.hitenine.filter.SysFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>SysFilter</filter-name>
    <url-pattern>/jsp/*</url-pattern>
</filter-mapping>

码农公寓

SMBMS

项目搭建准备工作

登录功能实现

登录功能优化

注销功能

登录拦截优化

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