SMBMS
HNU Peter Lv2
  2022-04-26 10:12:02 2022-04-26 10:12      

超市订单管理系统

1、整体架构

image-20220426101344224

2、项目搭建准备

  1. 按webapp步骤搭建web项目（目录结构）—->

  2. 配置Tomcat—–>

  3. 导入项目依赖jar（基本依赖）—->

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<dependencies>
  <dependency>
    <groupId>jakarta.servlet</groupId>
    <artifactId>jakarta.servlet-api</artifactId>
    <version>5.0.0</version>
  </dependency>
  <dependency>
    <groupId>jakarta.servlet.jsp</groupId>
    <artifactId>jakarta.servlet.jsp-api</artifactId>
    <version>3.0.0</version>
  </dependency>
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.21</version>
  </dependency>
</dependencies>

  1. 创建项目包结构

  2. 编写实体类

​ ORM（表<—->类）映射，可以在IDEA中根据数据库表自动生成（需要少量修改）。

  1. 编写基础公共类
  • 数据库配置文件
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driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/smbms?useUnicode=true&characterEncoding=utf-8
user=root
password=123456
  • 编写数据库公共类
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package com.pans.dao;

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

//操作数据库的基类
public class BaseDao {
    private static String driver;
    private static String url;
    private static String username;
    private static String password;
    //静态代码块，类加载时初始化
    static {

        Properties properties = new Properties();
        //通过类加载器读取资源
        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");
    }

    //获取数据库链接
    public static Connection getConnection() throws ClassNotFoundException, SQLException {
        //Connection connection=null;
        Class.forName(driver);
        Connection connection = DriverManager.getConnection(url, username, password);
        return connection;
    }

    //编写查询公共类
    public static ResultSet excute(Connection connection,String sql,Object[] params,ResultSet resultSet, PreparedStatement preparedStatement) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++) {
            preparedStatement.setObject(i+1,params[i]);
        }
        resultSet = preparedStatement.executeQuery();
        return resultSet;
    }

    //编写增删改公共方法
    public static int excute(Connection connection,String sql,Object[] params, PreparedStatement preparedStatement) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++) {
            preparedStatement.setObject(i+1,params[i]);
        }
        int updateRows= preparedStatement.executeUpdate();
        return updateRows;
    }

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

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

  • 编写字符编码过滤器并在web.xml中注册
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package com.pans.filter;

import javax.servlet.*;
import java.io.IOException;

public class CharacterEncodingFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        Filter.super.init(filterConfig);
    }

    @Override
    public void destroy() {
        Filter.super.destroy();
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        chain.doFilter(request,response);
    }
}

  1. 导入静态资源

3、登录功能实现

image-20220426164511812

1. 编写前端页面login.jsp

2. 设置首页为login.jsp

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<welcome-file-list>
    <welcome-file>login.jsp</welcome-file>
</welcome-file-list>

3. 编写Dao层登录用户登陆的接口

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package com.pans.dao.user;

import com.pans.pojo.User;

import java.sql.Connection;

public interface UserDao {
    //得到登录的用户信息
    public User getLoginUser(Connection connection, String userCode) throws Exception;
}

4. 编写Dao接口的实现类

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package com.pans.dao.user;

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

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class UserDaoImpl implements UserDao{
    @Override
    public User getLoginUser(Connection connection, String userCode) throws Exception {
        PreparedStatement pstm = null;
        ResultSet rs = null;
        User user = null;
        if(null != connection){
            String sql = "select * from smbms_user where userCode=?";
            Object[] params = {userCode};
            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;
    }
}

5. 编写业务层接口及其实现类

==此时在做测试的遇到的bug：==

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package com.pans.service.user;

import com.pans.dao.BaseDao;
import com.pans.dao.user.UserDao;
import com.pans.dao.user.UserDaoImpl;
import com.pans.pojo.User;
import org.junit.Test;

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

public class UserServiceImpl implements UserService{

    //业务层都会调用dao层，所以需要引入dao层
    private UserDao userDao;

    public UserServiceImpl() {
       userDao = new UserDaoImpl();
    }

    @Override
    public User login(String userCode, String password) {
        Connection connection = null;
        User user = new User();
        try {
            connection = BaseDao.getConnection();
            //通过业务层调用对应的具体数据库操作
           user = userDao.getLoginUser(connection, userCode);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            BaseDao.closeResource(connection,null,null);
        }
        return user;
    }
}

==bug1：==

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java.sql.SQLException: Access denied for user ''@'localhost' (using password: YES)

错误原因：

BaseDao里面

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username = properties.getProperty("username");

对应的db.properties

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user=root
password=123456

注意配置文件里的名字要和BaseDao一致！！！

==bug2：==

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java.sql.SQLException: The server time zone value '�й���׼ʱ��' is unrecognized or represents more than one time

错误原因：

需要在配置文件的url里面加上时区！！！

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url=jdbc:mysql://localhost:3306/smbms?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai

6. 业务层接口

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package com.pans.service.user;

import com.pans.pojo.User;

import java.sql.SQLException;

public interface UserService {

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

7. 业务层实现

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package com.pans.service.user;

import com.pans.dao.BaseDao;
import com.pans.dao.user.UserDao;
import com.pans.dao.user.UserDaoImpl;
import com.pans.pojo.User;
import org.junit.Test;

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

public class UserServiceImpl implements UserService{

    //业务层都会调用dao层，所以需要引入dao层
    private UserDao userDao;

    public UserServiceImpl() {
       userDao = new UserDaoImpl();
    }

    @Override
    public User login(String userCode, String password) {
        Connection connection = null;
        User user = new User();
        try {
            connection = BaseDao.getConnection();
            //通过业务层调用对应的具体数据库操作
           user = userDao.getLoginUser(connection, userCode);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            BaseDao.closeResource(connection,null,null);
        }
        return user;
    }

    @Test
    public void test(){
        UserServiceImpl userService = new UserServiceImpl();
        User admin = userService.login("wen", "123");
        System.out.println(admin.getUserPassword());
    }
}

8. 编写Servlet处理请求

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package com.pans.servlet.user;

import com.pans.pojo.User;
import com.pans.service.user.UserServiceImpl;
import com.pans.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 {
    //控制层调用业务层代码

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


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("ServletLogin===========start!!");

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

        //和数据库密码进行对比，调用业务层
        UserServiceImpl userService = new UserServiceImpl();
        User user = userService.login(userCode, password);   //查此人返回信息

        if(user!=null){ //查有此人，继续验证密码是否正确
            if(user.getUserPassword().equals(password)){
                //将用户信息放到Session中
                req.getSession().setAttribute(Constants.USER_SESSION,user);
                //跳转到首页
                resp.sendRedirect("jsp/frame.jsp");
            }else{
                //密码错误，无法登录
                //转发登录界面，顺带提示，密码错误
                req.setAttribute("error","密码错误！");
                req.getRequestDispatcher("login.jsp").forward(req,resp);
            }
        }else{//查无此人，无法登录
            //转发登录界面，顺带提示，用户名或者密码错误
            req.setAttribute("error","用户名不存在");
            req.getRequestDispatcher("login.jsp").forward(req,resp);
        }

    }
}

9. 添加servlet依赖

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

4、登录功能优化

1、注销功能

  • 编写Servlet并注册
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package com.pans.servlet.user;

import com.pans.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 LoginoutServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //移除用户Seession
        req.getSession().removeAttribute(Constants.USER_SESSION);

        resp.sendRedirect(req.getContextPath()+"/login.jsp ");
    }
}

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<!--注销页面-->
    <servlet>
        <servlet-name>LoginoutServlet</servlet-name>
        <servlet-class>com.pans.servlet.user.LoginoutServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LoginoutServlet</servlet-name>
        <url-pattern>/jsp/logout.do</url-pattern>
    </servlet-mapping>

2、登录拦截

  • 编写Servlet过滤器+注册过滤器
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package com.pans.filter;

import com.pans.pojo.User;
import com.pans.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 {
        Filter.super.init(filterConfig);
    }

    @Override
    public void destroy() {
        Filter.super.destroy();
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        //由于servletRequest无法获取Session,转化为
        HttpServletRequest request1 = (HttpServletRequest) request;
        HttpServletResponse response1 = (HttpServletResponse) response;

        //过滤器，从Session中获取用户信息
        User user = (User) request1.getSession().getAttribute(Constants.USER_SESSION);

        if(user==null){  //已经被移除或者注销未登录
            response1.sendRedirect("/smbms/error.jsp");
        }else{
            chain.doFilter(request,response);
        }

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

==此时遇到一个bug：==

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class org.apache.catalina.connector.RequestFacade cannot be cast to class javax.servlet.http.HttpServletResponse (org.apache.catalina.connector.RequestFacade and javax.servlet.http.HttpServletResponse are in unnamed module of loader java.net.URLClassLoader @33723e30)

经过检查发现在过滤器中==类型转换错误：==

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HttpServletResponse response1 = (HttpServletResponse) response;

写成了：==（由于使用了快速提示没有注意到名字！）==

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HttpServletResponse response1 = (HttpServletResponse) resquest;

3、修改密码

  1. 导入/编写前端js界面
  2. 理清思路架构

image-20220427103034622

  1. UserDao接口
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//修改当前用户密码
public  int updatePwd(Connection connection,String userCode,String password) throws SQLException;
  1. UserDao实现类
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//修改用户密码
@Override
public int updatePwd(Connection connection,String userCode, String  password) throws SQLException {
    int rows=0;
    if(connection!=null){
        String sql="update smbms_user set userPassword=? where userCode=?";
        PreparedStatement preparedStatement=null;
        Object[] params = {password,userCode};
        rows = BaseDao.execute(connection,preparedStatement,sql,params);
        BaseDao.closeResource(connection,preparedStatement,null);
    }
    return rows;
}
  1. Service接口
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//修改用户密码
public boolean updatePwd(String userCode,String password);
  1. Service实现类
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//根据用户ID修改用户密码
@Override
public boolean updatePwd(String userCode, String password) {

    boolean flag=false;
    Connection connection = null;
    try {
        connection = BaseDao.getConnection();
        if(userDao.updatePwd(connection,userCode,password)>0){
            flag=true;
        }
    } catch (SQLException | ClassNotFoundException e) {
        e.printStackTrace();
    } finally {
        BaseDao.closeResource(connection,null,null);
    }
    return flag;

}
  1. Servlet实现
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package com.pans.servlet.user;

import com.pans.pojo.User;
import com.pans.service.user.UserServiceImpl;
import com.pans.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 updatePwd extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取用户userCode
        Object attribute = req.getSession().getAttribute(Constants.USER_SESSION);
        String newpassword = req.getParameter("newpassword");

//        System.out.println(attribute);
//
//        System.out.println("进入updatePwd-Servlet====="+newpassword);

        boolean flag=false;
        if(attribute!=null&&newpassword!=null&&newpassword.length()!=0){
            UserServiceImpl userService = new UserServiceImpl();
            flag=userService.updatePwd(((User)attribute).getUserCode(),newpassword);
            //System.out.println("业务层返回结果为："+flag);
            if(flag){
                req.setAttribute("message","密码修改成功，请返回重新登录！");
                //移除当前Session
                req.getSession().removeAttribute(Constants.USER_SESSION);
                //跳转到登录页
                //System.out.println("准备重新跳转到登录页！");
               resp.sendRedirect("/smbms/login.jsp");
            }
        }else{
            req.setAttribute("message","密码修改失败！");
            req.getRequestDispatcher("pwdmodify.jsp").forward(req,resp);
        }
       // req.getRequestDispatcher("pwdmodify.jsp").forward(req,resp);

    }

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

4、Ajax验证旧密码

  1. 导入相关依赖
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  阿里巴巴工具转换（map-->json）
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.75</version>
  </dependency>
  1. 旧密码验证只需要在前端验证（旧密码从Session中获得）
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    //前端验证用户旧密码
    public void pwdModify(HttpServletRequest req, HttpServletResponse resp){
        //获取前端用户密码
        String oldPassword = req.getParameter("oldpassword");

        //System.out.println(oldPassword);

        //获取session里面的密码
        Object attribute = req.getSession().getAttribute(Constants.USER_SESSION);
        String userRealPassword = ((User) attribute).getUserPassword();

       // System.out.println(userRealPassword);

        Map<String, String> resultMap = new HashMap<String,String>();
        if(attribute==null){  //Session失效
            resultMap.put("result","sessionerror");
        }else if(StringUtils.isNullOrEmpty(oldPassword)){  //密码为空
            resultMap.put("result","error");
        }else{
            if(oldPassword.equals(userRealPassword)){//密码正确
                resultMap.put("result","true");
            }else{
                resultMap.put("result","false");
            }
        }

        //以json格式响应到客户端
        resp.setContentType("application/json");
        try {
            PrintWriter writer = resp.getWriter();
            //JSONArray 阿里巴巴的JSON工具类：转换格式： MAP---->JSON
            writer.write(JSONArray.toJSONString(resultMap));
            writer.flush();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
 }
前端响应结果为：{"result":"true/false/..."}

  1. 复用servlet（==因为在前端中的action路径都是该servlet的路径==）
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protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    //先获取前端参数以确定服务类型
    String method = req.getParameter("method");
    if(method.equals("pwdmodify")){ //验证旧密码
        this.pwdModify(req,resp);
    }else if(method.equals("savepwd")){//修改密码
         this.updatePassword(req,resp);
    }
}

==注意js文件渲染后的乱码问题：==将js文件用文本打开，然后另存为的时候选择utf-8 BOOM编码格式即可！！！