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超适合练手的一套JavaWeb项目（超市后台管理系统）

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一、项目搭建准备工作

1.搭建一个maven web项目
2.配置Tomcat
3.测试项目是否能够跑起来
4.导入项目中遇到的jar包
5.创建项目结构

6.编写实体类

ORM映射：表类映射

7.编写基础公共类

1.数据库配置文件

db.properties文件代码

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306?useUnicode=true&characterEncoding=utf-8
username=root
password=111111

2.编写数据库的公共类

java代码

package com.syj.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");
    }
    //获取数据库的链接
    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 {
       preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i < params.length; i++) {
            //setObject,占位符从1开始，但是我们的数组是从0开始！
            preparedStatement.setObject(i+1,params[i]);
        }
        resultSet = preparedStatement.executeQuery();
        return resultSet;
    }
    //编写增删改查公共方法
    public static int execute( Connection connection,String sql,Object[] params, PreparedStatement preparedStatement ) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);
        for (int i = 0; i < params.length; i++) {
            //setObject,占位符从1开始，但是我们的数组是从0开始！
            preparedStatement.setObject(i+1,params[i]);
        }
        int updateRows = preparedStatement.executeUpdate();
        return updateRows;
    }
    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;
    }
}

3.编写字符编码过滤器

8.导入静态资源

二、登录功能实现

1.编写前端页面

2.设置欢迎界面

xml代码

<!--设置欢迎页面-->
    <welcome-file-list>
        <welcome-file>login.jsp</welcome-file>
    </welcome-file-list>

3.编写dao层登录用户的接口

java dao层接口代码

package com.syj.dao.user;
import com.syj.entity.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

java dao接口的实现类代码

package com.syj.dao.user;
import com.syj.dao.BaseDao;
import com.syj.entity.User;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class UserDaoImpl implements UserDao{
    //得到要登录的用户
    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,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.业务层接口

java service接口代码

package com.syj.service.user;
import com.syj.entity.User;
public interface UserService {
        //用户登录
    public User login(String userCode,String password);
}

6.业务层实现类

java serviceImpl实现类代码

package com.syj.service.user;
import com.syj.dao.BaseDao;
import com.syj.dao.user.UserDao;
import com.syj.dao.user.UserDaoImpl;
import com.syj.entity.User;
import java.sql.Connection;
import java.sql.SQLException;
public class UserServiceImpl implements UserService{
    private UserDao userDao;
    public UserServiceImpl(){
        userDao = new UserDaoImpl();
    }
    public User login(String userCode, String password) {
        Connection connection = null;
        User user = null;
        connection = BaseDao.getConnection();
        try {
            user = userDao.getLoginUser(connection,userCode);
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            BaseDao.closeResource(connection,null,null);
        }
        return user;
    }
}

7.编写Servlet

java 代码

package com.syj.servlet;
import com.syj.entity.User;
import com.syj.service.user.UserService;
import com.syj.service.user.UserServiceImpl;
import com.syj.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 {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String userCode = req.getParameter("userCode");
        String userPassword = req.getParameter("userPassword");
        UserService userService = new UserServiceImpl();
        User user = userService.login(userCode, userPassword);
        if(user != null){
            req.getSession().setAttribute(Constants.USER_SESSION,user);
            resp.sendRedirect("jsp/frame.jsp");
        }else{
            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);
    }
}

8.注册servlet

xml代码

<servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>com.syj.servlet.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成功

三、登陆功能优化

注销功能：

思路：移除Session,返回登录界面
java servlet代码

package com.syj.servlet;
import com.syj.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 {
      req.getSession().removeAttribute(Constants.USER_SESSION);
      resp.sendRedirect("/login.jsp");
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

xml 代码

<!--注销-->
    <servlet>
        <servlet-name>LogoutServlet</servlet-name>
        <servlet-class>com.syj.servlet.LogoutServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LogoutServlet</servlet-name>
        <url-pattern>/jsp/logout.do</url-pattern>
    </servlet-mapping>

四、登录拦截优化

编写一个过滤器并注册

java 代码

package com.syj.filter;
import com.syj.entity.User;
import com.syj.util.Constants;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class SysFilter implements Filter {
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) resp;
        User user = (User) request.getSession().getAttribute(Constants.USER_SESSION);
        if(user==null){
            response.sendRedirect("/smbms/error.jsp");
        }else{
            chain.doFilter(req,resp);
        }
    }
    public void destroy() {
    }
}

xml 代码

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

测试，登录，注销，权限，以上功能都要保证执行成功

五、密码修改

1.导入前端素材

pwdmodify.jsp

<li.><a.href=“${pageContext.request.contextPath }/jsp/pwdmodify.jsp”>密码修改</li.>

2.写项目，建议从底层向上写

3.UserDao接口

//修改用户密码
    public int updatePwd(Connection connection,int id,int password) throws SQLException;

4.UserDao接口实现类

//修改用户密码
    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,pstm,sql,params);
            BaseDao.closeResource(null,pstm,null);
        }
        return execute;
    }

5.UserService层

  //根据用户Id修改密码
    public boolean updatePwd(int id,int pwd);

6.UserService实现类

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 e) {
            e.printStackTrace();
        }finally {
            BaseDao.closeResource(connection,null,null);
        }
        return false;
    }

7. servlet控制器层

记得实现复用，需要提取方法

 @Override
package com.mario.servlet;
import com.mario.entity.User;
import com.mario.service.user.UserService;
import com.mario.service.user.UserServiceImpl;
import com.mario.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 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){
        Object obj = req.getSession().getAttribute(Constants.USER_SESSION);
        String newpassword = req.getParameter("newpassword");
        System.out.println(newpassword);
        boolean flag = false;
        if(obj != null && newpassword != null){
            UserService userService = new UserServiceImpl();
            flag = userService.updatePwd(((User) obj).getId(), newpassword);
            if(flag){
                req.setAttribute("message","修改密码成功");
                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. 测试

优化密码修改使用Ajax

1.阿里巴巴的fastjson

pom.xml

<dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.61</version>
    </dependency>

2.后台修改的代码

package com.mario.servlet;
import com.alibaba.fastjson.JSONArray;
import com.mario.entity.User;
import com.mario.service.user.UserService;
import com.mario.service.user.UserServiceImpl;
import com.mario.util.Constants;
import com.mysql.jdbc.StringUtils;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
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);
        }else if(method.equals("pwdmodify") && method != null){
            this.pwdModify(req,resp);
        }
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
    //修改密码
    public void updatePwd(HttpServletRequest req, HttpServletResponse resp){
        Object obj = req.getSession().getAttribute(Constants.USER_SESSION);
        String newpassword = req.getParameter("newpassword");
        System.out.println(newpassword);
        boolean flag = false;
        if(obj != null && newpassword != null){
            UserService userService = new UserServiceImpl();
            flag = userService.updatePwd(((User) obj).getId(), newpassword);
            if(flag){
                req.setAttribute("message","修改密码成功");
                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();
        }
    }
    //验证旧密码,session中有用户的密码
    public void pwdModify(HttpServletRequest req, HttpServletResponse resp){
        Object obj = req.getSession().getAttribute(Constants.USER_SESSION);
        String oldpassword = req.getParameter("oldpassword");
        Map<String, String> resultMap = new HashMap<String, String>();
        if(obj==null){
            resultMap.put("result","sessionerror");
        }else if(StringUtils.isNullOrEmpty(oldpassword)){
            resultMap.put("result","error");
        }else{
            String userPassword = ((User) obj).getUserPassword();
            if(oldpassword.equals(userPassword)){
                resultMap.put("result","true");
            }else{
                resultMap.put("result","false");
            }
        }
        try {
            resp.setContentType("application/json");
            PrintWriter writer = resp.getWriter();
            writer.write(JSONArray.toJSONString(resultMap));
            writer.flush();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

3.测试

六、用户管理实现

1.获取用户数量

1.UserDao

 //查询用户总数
    public int getUserCount(Connection connection,String username,int userRole) throws SQLException;

2.UserDaoImpl

    public int getUserCount(Connection connection, String username, int userRole) throws SQLException {
        PreparedStatement pstm = null;
        ResultSet rs = null;
        int count = 0;
        if(connection != null){
            StringBuilder sql = new StringBuilder();
            sql.append("select count(1) as count from smbms_user u,smbms_role r where u.userRole = r.id");
            ArrayList<Object> list = new ArrayList<Object>();
            if(!StringUtils.isNullOrEmpty(username)){
                sql.append(" and u.userName like ? ");
                list.add("%"+username+"%");
            }
            if(userRole>0){
                sql.append(" and u.userRole = ? ");
                list.add(userRole);
            }
            Object[] params = list.toArray();
            rs = BaseDao.execute(connection,pstm,rs,sql.toString(),params);
            if(rs.next()){
                count = rs.getInt("count");
            }
            BaseDao.closeResource(null,pstm,rs);
        }
        return count;
    }

3.UserService

 //查询记录数
    public int getUserCount(String username,int userRole);

4.UserServiceImpl

 public int getUserCount(String username, int userRole) {
        Connection connection = null;
        int count = 0;
        try {
            connection = BaseDao.getConnection();
            count = userDao.getUserCount(connection,username,userRole);
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            BaseDao.closeResource(connection,null,null);
        }
        return count;
    }

2.用户列表页导入

1.UserDao

 //通过用户输入的条件查询用户列表
    public List<User> getUserList(Connection connection, String userName, int userRole, int currentPageNo, int pageSize) throws  Exception;

2.UserDaoImpl

 //通过用户输入的条件查询用户列表
    public List<User> getUserList(Connection connection, String userName, int userRole, int currentPageNo, int pageSize) throws Exception {
        List<User> userList = new ArrayList<User>();
        PreparedStatement pstm=null;
        ResultSet rs=null;
        if(connection!=null){
            StringBuffer sql = new StringBuffer();
            sql.append("select u.*,r.roleName as userRoleName from smbms_user u,smbms_role r where u.userRole = r.id");
            List<Object> list = new ArrayList<Object>();
            if(!StringUtils.isNullOrEmpty(userName)){
                sql.append(" and u.userName like ?");
                list.add("%"+userName+"%");
            }
            if(userRole > 0){
                sql.append(" and u.userRole = ?");
                list.add(userRole);
            }
            sql.append(" order by creationDate DESC limit ?,?");
            currentPageNo = (currentPageNo-1)*pageSize;
            list.add(currentPageNo);
            list.add(pageSize);
            Object[] params = list.toArray();
            System.out.println("sql ----> " + sql.toString());
            rs = BaseDao.execute(connection,pstm,rs,sql.toString(),params);
            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;
    }

3.UserService

 //根据条件查询用户列表
    public List<User> getUserList(String queryUserName, int queryUserRole, int currentPageNo, int pageSize);

4.UserServiceImpl

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 (Exception e) {
            e.printStackTrace();
        }finally{
            BaseDao.closeResource(connection, null, null);
        }
        return userList;
    }

3.获取角色操作

1.RoleDao

//获取角色列表
    public List<Role> getRoleList(Connection connection) throws SQLException;

2.RoleDaoImpl

package com.mario.dao.role;
import com.mario.dao.BaseDao;
import com.mario.entity.Role;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class RoleDaoImpl implements RoleDao{
    //获取角色列表
    public List<Role> getRoleList(Connection connection) throws SQLException {
        PreparedStatement pstm = null;
        ResultSet rs = null;
        ArrayList<Role> rolesList = new ArrayList<Role>();
        if(connection != null){
            String sql = "select * from smbms_role";
            Object[] params = {};
            rs =  BaseDao.execute(connection,pstm,rs,sql,params);
            while (rs.next()){
                Role _role = new Role();
                _role.setId( rs.getInt("id"));
                _role.setRoleCode( rs.getString("roleCode"));
                _role.setRoleName( rs.getString("roleName"));
                rolesList.add(_role);
            }
            BaseDao.closeResource(null, pstm, rs);
        }
        return rolesList;
    }
}

3.RoleService

 //获取角色列表
    public List<Role> getRoleList();

4.RoleServiceImpl

package com.mario.service.role;
import com.mario.dao.BaseDao;
import com.mario.dao.role.RoleDao;
import com.mario.dao.role.RoleDaoImpl;
import com.mario.entity.Role;
import java.sql.Connection;
import java.util.List;
public class RoleServiceImpl implements RoleService{
    private RoleDao roleDao;
    public RoleServiceImpl(){
        roleDao = new RoleDaoImpl();
    }
    //获取角色列表
    public List<Role> getRoleList() {
        Connection connection=null;
        List<Role> roleList=null;
        try {
            connection= BaseDao.getConnection();
            roleList = roleDao.getRoleList(connection);
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            BaseDao.closeResource(connection,null,null);
        }
        return roleList;
    }
}

4.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，页面的大小
用户列表展示

返回前端

package com.mario.servlet;

import com.alibaba.fastjson.JSONArray;
import com.mario.entity.Role;
import com.mario.entity.User;
import com.mario.service.role.RoleService;
import com.mario.service.role.RoleServiceImpl;
import com.mario.service.user.UserService;
import com.mario.service.user.UserServiceImpl;
import com.mario.util.Constants;
import com.mario.util.PageSupport;
import com.mysql.jdbc.StringUtils;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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);
    }else if(method.equals("pwdmodify") && method != null){
        this.pwdModify(req,resp);
    }else if(method.equals("query") && method != null){
        this.query(req,resp);
    }
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    doGet(req, resp);
}
public void query(HttpServletRequest req, HttpServletResponse resp){
    //接收前端传来的参数
    String queryUserName = req.getParameter("queryname");
    String temp = req.getParameter("queryUserRole");//从前端传回来的用户角色码不知是否为空或者是有效角色码，所以暂存起来
    String pageIndex = req.getParameter("pageIndex");
    int queryUserRole=0;
    //通过UserServiceImpl得到用户列表,用户数
    UserServiceImpl userService = new UserServiceImpl();
    List<User> userList = null;//用来存储用户列表
    //设置每页显示的页面容量
    int pageSize = 5;
    //设置当前的默认页码
    int currentPageNo=1;
    //前端传来的参数若不符合查询sql语句，即如果用户不进行设置，值为空会影响sql查询，需要给它们进行一些约束
    if(queryUserName==null){//这里为空，说明用户没有输入要查询的用户名，则sql语句传值为""，%%，会查询所有记录
        queryUserName="";
    }
    if(temp!=null && !temp.equals("")){
        //不为空，说明前端有传来的用户所设置的userCode，更新真正的角色码
        queryUserRole=Integer.parseInt(temp);//强制转换，前端传递的参数都是默认字符串，要转成int类型
    }
    if(pageIndex!=null){//说明当前用户有进行设置跳转页面
        currentPageNo=Integer.valueOf(pageIndex);
    }
    //有了用户名和用户角色后可以开始查询了，所以需要显示当前查询到的总记录条数
    int totalCount = userService.getUserCount(queryUserName, queryUserRole);
    //根据总记录条数以及当前每页的页面容量可以算出，一共有几页，以及最后一页的显示条数
    PageSupport pageSupport = new PageSupport();
    pageSupport.setCurrentPageNo(currentPageNo);
    pageSupport.setPageSize(pageSize);
    pageSupport.setTotalCount(totalCount);
    //可显示的总页数
    int totalPageCount=pageSupport.getTotalPageCount();
    //约束首位页，即防止用户输入的页面索引小于1或者大于总页数
    if(currentPageNo<1){
        currentPageNo=1;
    }else if(currentPageNo>totalPageCount){
        currentPageNo=totalPageCount;
    }
    //有了，待查询条件，当前页码，以及每页的页面容量后，就可以给出每页的具体显示情况了
     userList = userService.getUserList(queryUserName, queryUserRole, currentPageNo, pageSize);
    req.setAttribute("userList",userList);
    //通过RoleServiceImpl得到角色表
    RoleService roleService = new RoleServiceImpl();
    List<Role> roleList = roleService.getRoleList();//用来存储角色表
    //得到了用户表与角色表以及各种经过处理后的参数，都存进req中
    req.setAttribute("roleList",roleList);
    req.setAttribute("totalCount", totalCount);
    req.setAttribute("currentPageNo", currentPageNo);
    req.setAttribute("totalPageCount", totalPageCount);
    req.setAttribute("queryUserName", queryUserName);
    req.setAttribute("queryUserRole", queryUserRole);
    //将所得到的的所有req参数送回给前端
    try {
        req.getRequestDispatcher("userlist.jsp").forward(req,resp);
    } catch (ServletException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}
//修改密码
public void updatePwd(HttpServletRequest req, HttpServletResponse resp){
    Object obj = req.getSession().getAttribute(Constants.USER_SESSION);
    String newpassword = req.getParameter("newpassword");
    System.out.println(newpassword);
    boolean flag = false;
    if(obj != null && newpassword != null){
        UserService userService = new UserServiceImpl();
        flag = userService.updatePwd(((User) obj).getId(), newpassword);
        if(flag){
            req.setAttribute("message","修改密码成功");
            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();
    }
}
//验证旧密码,session中有用户的密码
public void pwdModify(HttpServletRequest req, HttpServletResponse resp){
    Object obj = req.getSession().getAttribute(Constants.USER_SESSION);
    String oldpassword = req.getParameter("oldpassword");
    Map<String, String> resultMap = new HashMap<String, String>();
    if(obj==null){
        resultMap.put("result","sessionerror");
    }else if(StringUtils.isNullOrEmpty(oldpassword)){
        resultMap.put("result","error");
    }else{
        String userPassword = ((User) obj).getUserPassword();
        if(oldpassword.equals(userPassword)){
            resultMap.put("result","true");
        }else{
            resultMap.put("result","false");
        }
    }
    try {
        resp.setContentType("application/json");
        PrintWriter writer = resp.getWriter();
        writer.write(JSONArray.toJSONString(resultMap));
        writer.flush();
        writer.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

}

七、订单管理（增删改查）

八、供应商管理（增删改查）

文章上面的代码只有一部分具体看项目里面的代码…

&

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超适合练手的一套JavaWeb项目 （超市后台管理系统）

GIF动态图演示

百度百度网盘提取项目 带数据库！[链接]:https://pan.baidu.com/s/13F2rxszZRLGDt9pr6ixYUg提取码：关注私信我发送！

一、项目搭建准备工作

6.编写实体类

7.编写基础公共类

1.数据库配置文件

2.编写数据库的公共类

3.编写字符编码过滤器

8.导入静态资源

二、登录功能实现

1.编写前端页面

2.设置欢迎界面

3.编写dao层登录用户的接口

4.编写dao接口的实现类

5.业务层接口

6.业务层实现类

7.编写Servlet

8.注册servlet

9.测试访问确保以上功能成功

三、登陆功能优化

注销功能：

四、登录拦截优化

编写一个过滤器并注册

五、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接口实现类

5.UserService层

6.UserService实现类

7. servlet控制器层

8. 测试

优化密码修改使用Ajax

1.阿里巴巴的fastjson

2.后台修改的代码

3.测试

六、用户管理实现

1.获取用户数量

1.UserDao

2.UserDaoImpl

3.UserService

4.UserServiceImpl

2.用户列表页导入

1.UserDao

2.UserDaoImpl

3.UserService

4.UserServiceImpl

3.获取角色操作

1.RoleDao

2.RoleDaoImpl

3.RoleService

4.RoleServiceImpl

4.用户显示的Servlet

七、订单管理（增删改查）

八、供应商管理（增删改查）

文章上面的代码只有一部分具体看项目里面的代码…

&

&

&

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超适合练手的一套JavaWeb项目（超市后台管理系统）

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