SMBMS(Supermarket Billing Management System )

SMBMS(Supermarket Billing Management System )

1. 项目架构

graph LR
id1[SMBMS]

id2[登录注销]
id3[用户管理]
id4[订单管理]
id5[供应商管理]

id6[增]
id7[删]
id8[改]
id9[查]
id10[ ]
id11[数据库]

id1 --> id2
id1 --> id3
id1 --> id4
id1 --> id5

id10 --> id6
id10 --> id7
id10 --> id8
id10 --> id9

id3 --> id10
id4 --> id10
id5 --> id10

id6 --> id11
id7 --> id11
id8 --> id11
id9 --> id11

2. 项目搭建的准备工作

搭建一个Maven Web项目
配置Tomcat
测试项目是否能够跑起来
导入项目中需要用到的Jar包:jsp,Servlet, mysql驱动, jstl, standard
创建项目包结构
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(db.properties)

driver = com.mysql.jdbc.Driver

url = jdbc:mysql://localhost:3306/smbms?useUnicode=true&characterEncoding=utf-8

username = root

password = 123456

编写数据库公共类

package com.wang.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

        //由于getResourceAsStream中调用了private方法,此处必须用反射来读配置文件

        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();

        }

        return connection;

    }

    //编写查询公共类

    public static ResultSet execute(Connection connection, String sql, Object[] params, ResultSet resultSet, PreparedStatement preparedStatement) throws SQLException {

        //预编译的sql,在后面直接执行就可以了,不用传参

        preparedStatement = connection.prepareStatement(sql);

        //给预编译的sql传参数

        for (int i = 0; i < params.length; i++) {

            //setObject方法,占位符从1开始,但是我们的数组是从0开始的,因此下面写 i+1

            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, String sql, Object[] params, PreparedStatement preparedStatement) throws SQLException {

        preparedStatement = connection.prepareStatement(sql);

        //给预编译的sql传参数

        for (int i = 0; i < params.length; i++) {

            //setObject方法,占位符从1开始,但是我们的数组是从0开始的,因此下面写 i+1

            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 (resultSet != null){

            try {

                resultSet.close();

                //GC回收

                resultSet = null;

            } catch (SQLException e) {

                e.printStackTrace();

                flag = false;

            }

        }

        if (preparedStatement != null){

            try {

                preparedStatement.close();

                //GC回收

                preparedStatement = null;

            } catch (SQLException e) {

                e.printStackTrace();

                flag = false;

            }

        }

        if (connection != null){

            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并注册

package com.wang.filter;

import javax.servlet.*;

import java.io.IOException;

public class CharacterEncodingFilter implements Filter {

    @Override

    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @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);

    }

    @Override

    public void destroy() {

    }

}

<!--字符编码过滤器-->

<filter>

    <filter-name>CharacterEncodingFilter</filter-name>

    <filter-class>com.wang.filter.CharacterEncodingFilter</filter-class>

</filter>

<!--所有的url都会被过滤-->

<filter-mapping>

    <filter-name>CharacterEncodingFilter</filter-name>

    <url-pattern>/*</url-pattern>

</filter-mapping>

导入静态资源

3. 登陆功能实现

graph LR
id1[用户]
id2[登录界面 用户名 密码]
id3[判断是否登陆成功]
id4[失败]
id5[成功]
id6[后台首页]
id7[数据库]
id8[Dao]

id1 --> id2
id2 --login.dao--> id3
id3 --> id4
id4 --提示登录失败--> id2
id3 --> id5
id5 --跳转到后台首页--> id6
id6 --> id1
id3 --> id8
id8 --> id3
id7 --> id8
id8 --> id7

1. 编写前端页面

2. 设置首页

<!--设置欢迎页面-->

<welcome-file-list>

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

</welcome-file-list>

3. 编写Dao层,用户登录的接口

package com.wang.dao.user;

import com.wang.pojo.User;

import java.sql.Connection;

import java.sql.SQLException;

public interface UserDao {

    //得到登录的用户

    public User getLoginUser(Connection connection, String userCode) throws SQLException;

}

4. 编写Dao接口的实现类

package com.wang.dao.user;

import com.wang.dao.BaseDao;

import com.wang.pojo.User;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

public class UserDaoImpl implements UserDao {

    @Override

    public User getLoginUser(Connection connection, String userCode) throws SQLException {

        PreparedStatement pstm = null;

        ResultSet rs = null;

        User user = null;

        if (connection != null) {

            String sql = "select * from smbms_user where userCode = ?";

            Object[] params = {userCode};

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

           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. 业务层接口

package com.wang.service.user;

import com.wang.pojo.User;

public interface UserService {

    //用户登录

    public User login(String userCode, String password);

}

6. 业务层实现

package com.wang.service.user;

import com.wang.dao.BaseDao;

import com.wang.dao.user.UserDao;

import com.wang.dao.user.UserDaoImpl;

import com.wang.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,因此我们要引入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具体的数据库操作

            user = userDao.getLoginUser(connection, userCode);

        } catch (SQLException throwables) {

            throwables.printStackTrace();

        } finally {

            BaseDao.closeResource(connection, null, null);

        }

        return user;

    }

    @Test

    public void test() {

        UserServiceImpl userService = new UserServiceImpl();

        User admin = userService.login("admin", "1234567");

        System.out.println(admin.getUserPassword());

    }

}

7. 编写Servlet

package com.wang.servlet.user;

import com.wang.pojo.User;

import com.wang.service.user.UserServiceImpl;

import com.wang.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,调用业务层代码

    @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();

        //这里已经把登录的人给查出来了

        User user = userService.login(userCode, userPassword);

        if (user != null) {

            //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);

            //跳转到主页

            resp.sendRedirect("jsp/frame.jsp");

        }else {

            //查无此人,无法登陆

            //转发会登录页面,顺带提示用户名或密码错误

            req.setAttribute("error", "用户名或密码不正确");

            req.getRequestDispatcher("login.jsp").forward(req, resp);

        }

    }

    @Override

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        doGet(req, resp);

    }

}

8. 注册Servlet

<!--Servlet-->

<servlet>

    <servlet-name>LoginServlet</servlet-name>

    <servlet-class>com.wang.servlet.user.LoginServlet</servlet-class>

</servlet>

<servlet-mapping>

    <servlet-name>LoginServlet</servlet-name>

    <url-pattern>/login.do</url-pattern>

</servlet-mapping>

9. 测试访问,确保以上功能都能实现

4. 登录功能优化

注销功能:

思路:移除Session,返回登录页面

package com.wang.servlet.user;

import com.wang.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Session

        req.getSession().removeAttribute(Constants.USER_SESSION);

        //返回登录页面

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

    }

    @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.wang.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

编写过滤器并注册

package com.wang.filter;

import com.wang.pojo.User;

import com.wang.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 req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) req;

        HttpServletResponse response = (HttpServletResponse) resp;

        //过滤器,从session中获取用户

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

        //已经被移除或者被注销了,或者未登录

        if (user == null) {

            response.sendRedirect("/smbms/error.jsp");

        }else {

            chain.doFilter(req, resp);

        }

    }

    @Override

    public void destroy() {

    }

}

<!--用户登录过滤器-->

<filter>

    <filter-name>SysFilter</filter-name>

    <filter-class>com.wang.filter.SysFilter</filter-class>

</filter>

<!--所有的访问jsp目录下的资源都会被过滤-->

<filter-mapping>

    <filter-name>SysFilter</filter-name>

    <url-pattern>/jsp/*</url-pattern>

</filter-mapping>

5. 密码修改

1. 导入前端素材

2. 写项目,建议从底层向上写

3. UserDao接口

//修改当前用户的密码

public int updatePwd(Connection connection, int id, int password) throws SQLException;

4. UserDao实现类

//修改当前用户的密码,返回受影响的行数

@Override

public int updatePwd(Connection connection, int id, int password) throws SQLException {

    PreparedStatement pstm = null;

    int execute = 0;

    if (connection != null) {

        String sql = "update smbms_user set userPassword = ? where id = ?";

        Object params[] = {password, id};

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

        BaseDao.closeResource(null, pstm, null);

    }

    return execute;

}

5. UserService接口

//根据用户ID修改密码

public boolean updatePwd(int id, int pwd);

6. UserService实现类

@Override

public boolean updatePwd(int id, int pwd) {

    Connection connection = null;

    boolean flag = false;

    //修改密码

    try {

        connection = BaseDao.getConnection();

        if (userDao.updatePwd(connection, id, pwd) > 0) {

            flag = true;

        }

    } catch (SQLException throwables) {

        throwables.printStackTrace();

    } finally {

        BaseDao.closeResource(connection, null, null);

    }

    return flag;

}

7. 记得实现复用,需要提取出方法!

package com.wang.servlet.user;

import com.mysql.jdbc.StringUtils;

import com.wang.pojo.User;

import com.wang.service.user.UserService;

import com.wang.service.user.UserServiceImpl;

import com.wang.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;

//实现Servlet服用

public class UserServlet extends HttpServlet {

    @Override

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

        String method = req.getParameter("method");

        if (method.equals("savepwd") && method != null) {

            this.updatePwd(req, resp);

        }

    }

    @Override

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        doGet(req, resp);

    }

    public void updatePwd(HttpServletRequest req, HttpServletResponse resp) {

        //从Session里面拿ID

        Object o = req.getSession().getAttribute(Constants.USER_SESSION);

        String newpassword = req.getParameter("newpassword");

        boolean flag = false;

        if (o != null && !StringUtils.isNullOrEmpty(newpassword)) {

            UserService userService = new UserServiceImpl();

            flag = userService.updatePwd(((User) o).getId(), newpassword);

            if (flag) {

                req.setAttribute("message", "修改密码成功,请退出,使用新密码登录");

                //密码修改成功,移除当前Session

                req.getSession().removeAttribute(Constants.USER_SESSION);

            } else {

                req.setAttribute("message", "密码修改失败");

            }

        } else {

            req.setAttribute("message", "新密码有问题");

        }

        try {

            req.getRequestDispatcher("pwdmodify.jsp").forward(req,resp);

        } catch (ServletException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

}

8. 注册Servlet

<servlet>

    <servlet-name>UserServlet</servlet-name>

    <servlet-class>com.wang.servlet.user.UserServlet</servlet-class>

</servlet>

<servlet-mapping>

    <servlet-name>UserServlet</servlet-name>

    <url-pattern>/jsp/user.do</url-pattern>

</servlet-mapping>

6. 优化密码修改:使用AJAX

1. 引入阿里巴巴的fastjson

2. 后台代码修改

//验证旧密码,session中有用户的密码

public void pwdModify(HttpServletRequest req, HttpServletResponse resp) {

    //从Session里面拿ID

    Object o = req.getSession().getAttribute(Constants.USER_SESSION);

    String oldpassword = req.getParameter("oldpassword");

    //万能的map: 结果集

    Map<String, String> resultMap = new HashMap<>();

    if (o == null) {

        //Session失效了,Session过期了

        resultMap.put("result", "sessionerror");

    } else if (StringUtils.isNullOrEmpty(oldpassword)) {

        resultMap.put("result", "error");

    } else  {

        //Session用户的密码

        String userPassword = ((User) o).getUserPassword();

        if (oldpassword.equals(userPassword)) {

            resultMap.put("result", "true");

        } else {

            resultMap.put("result", "false");

        }

    }

    try {

        //限定响应返回的格式为json

        resp.setContentType("application/json");

        PrintWriter writer = resp.getWriter();

        //JSONArray 阿里巴巴的JSON工具类转换格式

        /*

        把resultMap转为JSON格式

         */

        writer.write(JSONArray.toJSONString(resultMap));

        writer.flush();

        writer.close();

    } catch (IOException e) {

        e.printStackTrace();

    }

}

7. 用户管理实现

1. 思路

graph LR
id1[用户]
id2[Servlet 1.处理请求 2.调用业务 3.返回页面]
id3[用户列表]
id4[角色列表]
id5[分页 pageSize&#40固定的&#41 总数&#40从数据库里查&#41]
id6[Service]
id7[Dao]
id8[数据库]

id1 --发起请求--> id2
id2 --返回前端页面--> id1
id2 --> id3
id2 --> id4
id2 --> id5

id3 --> id6
id4 --> id6
id5 --> id6
id6 --> id7
id7 --> id8

2. 导入分页的工具类

3. 用户列表页导入

userlist.jsp
rollpage.jsp

4. 获取用户数量

UserDao

//根据用户名或者角色查询用户总数

public int getUserCount(Connection connection, String username, int userRole) throws SQLException;

UserDaoImpl

//根据用户名或者角色查询用户总数

@Override

public int getUserCount(Connection connection, String username, int userRole) throws SQLException {

    PreparedStatement pstm = null;

    ResultSet rs = null;

    int count = 0;

    if (connection != null) {

        StringBuffer sql = new StringBuffer();

        sql.append("select count(1) as count from smbms_user as u, smbms_role as r where u.userRole = r.id");

        //存放我们的参数

        ArrayList<Object> list = new ArrayList<>();

        if (!StringUtils.isNullOrEmpty(username)) {

            sql.append(" and u.userName like ?");

            list.add("%" + username + "%");     //index = 0

        }

        if (userRole > 0) {

            sql.append(" and u.userRole like ?");

            list.add(userRole);     //index = 1

        }

        //把list转为数组

        Object[] objects = list.toArray();

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

        if (rs.next()) {

            //从结果集中获得最终的结果

            count = rs.getInt("count");

        }

        BaseDao.closeResource(null, pstm, rs);

    }

    return count;

}

UserService

//查询记录数

public int getUserCount(String username, int userRole);

UserServiceImpl

//查询记录数

@Override

public int getUserCount(String username, int userRole) {

    Connection connection = null;

    int userCount = 0;

    try {

        connection = BaseDao.getConnection();

        userCount = userDao.getUserCount(connection, username, userRole);

    } catch (SQLException throwables) {

        throwables.printStackTrace();

    } finally {

        BaseDao.closeResource(connection, null, null);

    }

    return userCount;

}

5. 获取用户列表

UserDao

//通过条件查询-userlist

public List<User> getUserList(Connection connection, String userName, int userRole, int currentPageNo, int pageSize) throws SQLException;

UserDaoImpl

//通过条件查询-userlist

@Override

public List<User> getUserList(Connection connection, String userName, int userRole, int currentPageNo, int pageSize) throws SQLException {

    PreparedStatement pstm = null;

    ResultSet rs = null;

    ArrayList<User> userList = new ArrayList<>();

    if (connection != null) {

        StringBuffer sql = new StringBuffer();

        sql.append("select u.*, r.roleName userRoleName from smbms_user as u join smbms_role as r on u.userRole = r.id");

        //存放我们的参数

        ArrayList<Object> list = new ArrayList<>();

        if (!StringUtils.isNullOrEmpty(userName)) {

            sql.append(" and u.userName like ?");

            list.add("%" + userName + "%");     //index = 0

        }

        if (userRole > 0) {

            sql.append(" and u.userRole like ?");

            list.add(userRole);     //index = 1

        }

        //在数据库中,分页使用limit   startIndex, pageSize;   总数

        //0,5

        //6,5

        //(当前页-1)*页面大小

        sql.append("order by creationDate desc limit ?, ?");

        currentPageNo = (currentPageNo - 1) * pageSize;

        list.add(currentPageNo);

        list.add(pageSize);

        Object[] params = list.toArray();

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

        while (rs.next()) {

            User _user = new User();

            _user.setId(rs.getInt("id"));

            _user.setUserCode(rs.getString("userCode"));

            _user.setUserName(rs.getString("userName"));

            _user.setGender(rs.getInt("gender"));

            _user.setBirthday(rs.getDate("birthday"));

            _user.setPhone(rs.getString("phone"));

            _user.setUserRole(rs.getInt("userRole"));

            _user.setUserRoleName(rs.getString("userRoleName"));

            userList.add(_user);

        }

        BaseDao.closeResource(null, pstm, rs);

    }

    return userList;

}

UserService

//根据条件查询用户列表

public List<User> getUserList(String queryUserName, int queryUserRole, int currentPageNo, int pageSize);

UserServiceImpl

//根据条件查询用户列表

@Override

public List<User> getUserList(String queryUserName, int queryUserRole, int currentPageNo, int pageSize) {

    Connection connection = null;

    List<User> userList = null;

    try {

        connection = BaseDao.getConnection();

        userList = userDao.getUserList(connection, queryUserName, queryUserRole, currentPageNo, pageSize);

    } catch (SQLException throwables) {

        throwables.printStackTrace();

    } finally {

        BaseDao.closeResource(connection, null, null);

    }

    return userList;

}

6. 获取角色操作

为了我们职责统一,可以把角色的操作单独放在一个包中,和POJO类对应

RoleDao

public interface RoleDao {

    //获取角色列表

    public List<Role> getRoleList(Connection connection) throws SQLException;

}

RoleDaoImpl

package com.wang.dao.role;

import com.wang.dao.BaseDao;

import com.wang.pojo.Role;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.List;

public class RoleDaoImpl implements RoleDao{

    //获取角色列表

    @Override

    public List<Role> getRoleList(Connection connection) throws SQLException {

        PreparedStatement pstm = null;

        ResultSet rs = null;

        List<Role> roleList = null;

        if (connection != null) {

            String sql = "select * from smbms_role";

            Object[] params = null;

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

            while (rs.next()) {

                Role _role = new Role();

                _role.setId(rs.getInt("id"));

                _role.setRoleName(rs.getString("roleName"));

                _role.setRoleCode(rs.getString("roleCode"));

                roleList.add(_role);

            }

            BaseDao.closeResource(null, pstm, rs);

        }

        return roleList;

    }

}

RoleService

package com.wang.service.role;

import com.wang.pojo.Role;

import java.util.List;

public interface RoleService {

    //获取角色列表

    public List<Role> getRoleList();

}

RoleServiceImpl

package com.wang.service.role;

import com.wang.dao.BaseDao;

import com.wang.dao.role.RoleDao;

import com.wang.dao.role.RoleDaoImpl;

import com.wang.pojo.Role;

import java.sql.Connection;

import java.sql.SQLException;

import java.util.List;

public class RoleServiceImpl implements RoleService{

    //引入Dao

    private RoleDao roleDao;

    public RoleServiceImpl() {

        roleDao = new RoleDaoImpl();

    }

    @Override

    public List<Role> getRoleList() {

        Connection connection = null;

        List<Role> roleList = null;

        try {

            connection = BaseDao.getConnection();

            roleList = roleDao.getRoleList(connection);

        } catch (SQLException throwables) {

            throwables.printStackTrace();

        } finally {

            BaseDao.closeResource(connection, null, null);

        }

        return roleList;

    }

}

7. 用户显示的Servlet

获取用户前端的数据(查询)
判断请求是否需要执行,看参数的值判断
为了实现分页,需要计算出当前页面和总页面,页面参数

//重点,难点

public void query(HttpServletRequest req, HttpServletResponse resp) {

    //查询用户列表

    //从前端获取数据

    String queryUserName = req.getParameter("queryname");

    String temp = req.getParameter("queryUserRole");

    String pageIndex = req.getParameter("pageIndex");

    int queryUserRole = 0;

    //获取用户列表

    UserServiceImpl userService = new UserServiceImpl();

    List<User> userList = null;

    //第一次走这个请求,一定是第一页,页面大小是固定的

    //可以把这个写在配置文件中,方便后期修改

    int pageSize = 5;

    int currentPageNo = 1;

    if (queryUserName == null) {

        queryUserName = "";

    }

    if (temp != null && !temp.equals("")) {

        queryUserRole = Integer.parseInt(temp);     //给查询赋值

    } if (pageIndex != null) {

        currentPageNo = Integer.parseInt(pageIndex);

    }

    //获取用户的总数(分页:上一页,下一页)

    int totalCount = userService.getUserCount(queryUserName, queryUserRole);

    //总页数支持

    PageSupport pageSupport = new PageSupport();

    pageSupport.setCurrentPageNo(currentPageNo);

    pageSupport.setPageSize(pageSize);

    pageSupport.setTotalCount(totalCount);

    int totalPageCount = pageSupport.getTotalPageCount();

    //控制首页和尾页

    //如果页面要小于1了,就显示第一页的东西

    if (totalPageCount < 1) {

        currentPageNo = 1;

    } else if (currentPageNo > totalPageCount){

        //当前页面大于最后一页

        currentPageNo = totalPageCount;

    }

    //获取用户列表展示

    userList = userService.getUserList(queryUserName, queryUserRole, currentPageNo, pageSize);

    req.setAttribute("userList", userList);

    //展示角色列表

    RoleServiceImpl roleService = new RoleServiceImpl();

    List<Role> roleList = roleService.getRoleList();

    req.setAttribute("roleList", roleList);

    req.setAttribute("queryUserName", queryUserName);

    req.setAttribute("queryUserRole", queryUserRole);

    //展示分页

    req.setAttribute("totalCount", totalCount);

    req.setAttribute("currentPageNo", currentPageNo);

    req.setAttribute("totalPageCount", totalPageCount);

    //返回前端

    try {

        req.getRequestDispatcher("userlist.jsp").forward(req, resp);

    } catch (ServletException e) {

        e.printStackTrace();

    } catch (IOException e) {

        e.printStackTrace();

    }

}

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SMBMS

SMBMS(Supermarket Billing Management System )

1. 项目架构

2. 项目搭建的准备工作

3. 登陆功能实现

1. 编写前端页面

2. 设置首页

3. 编写Dao层,用户登录的接口

4. 编写Dao接口的实现类

5. 业务层接口

6. 业务层实现

7. 编写Servlet

8. 注册Servlet

9. 测试访问,确保以上功能都能实现

4. 登录功能优化

5. 密码修改

1. 导入前端素材

2. 写项目,建议从底层向上写

3. UserDao接口

4. UserDao实现类

5. UserService接口

6. UserService实现类

7. 记得实现复用,需要提取出方法!

8. 注册Servlet

6. 优化密码修改:使用AJAX

1. 引入阿里巴巴的fastjson

2. 后台代码修改

7. 用户管理实现

1. 思路

2. 导入分页的工具类

3. 用户列表页导入

4. 获取用户数量

5. 获取用户列表

6. 获取角色操作

7. 用户显示的Servlet

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