javaweb超市管理系統demo

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SMBMS

數據庫:

項目搭建准備工作

1. 搭建一個maven web項目

2. 配置tomcat

3. 測試項目是否能夠跑起來

4. 導入項目中可能會遇到的Jar包
   jsp,Servlet,mysql驅動,jstl,stander......

     <dependency>
               <groupId>javax.servlet</groupId>
               <artifactId>servlet-api</artifactId>
               <version>2.5</version>
           </dependency>
           <dependency>
               <groupId>javax.servlet.jsp</groupId>
               <artifactId>javax.servlet.jsp-api</artifactId>
               <version>2.3.3</version>
           </dependency>
           <dependency>
               <groupId>mysql</groupId>
               <artifactId>mysql-connector-java</artifactId>
               <version>5.1.47</version>
           </dependency>
     <dependency>
               <groupId>javax.servlet.jsp.jstl</groupId>
               <artifactId>jstl-api</artifactId>
               <version>1.2</version>
           </dependency>
           <dependency>
               <groupId>taglibs</groupId>
               <artifactId>standard</artifactId>
               <version>1.1.2</version>
           </dependency>
   

5. 創建項目包結構

   

6. 編寫實體類
   ORM映射: 表-類映射

ORM映射: 表-類映射

7. 編寫基礎公共類

   1. 數據庫配置文件
      db.properties

      driver=com.mysql.jdbc.Driver
      url=jdbc:mysql://localhost:3306?useUnicode=true&characterEncoding=utf8&useSSL=true
      username=root
      password=123456
      

   2. 編寫數據庫的公共類(工具類)

      package com.tan.dao;
      
      import java.sql.ResultSet;
      import java.sql.*;
      
      import java.io.IOException;
      import java.io.InputStream;
      import java.sql.Connection;
      import java.util.Properties;
      
      /**
       * @author null
       * @date 2020/5/19
       */
      
      //操作數據類的公共類
      public class BaseDao {
          private static String driver;
          private static String url;
          private static String username;
          private static String password;
      
          //靜態代碼塊,類加載的時候就初始化了
          static {
              Properties properties = new Properties();
              //通過類加載器讀取相應的資源
              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");
          }
      
          //獲取數據庫的鏈接
          public static Connection getConnection() {
              Connection connection = null;
              try {
                  Class.forName(driver);
                  connection = DriverManager.getConnection(url, username, password);
              } catch (Exception e) {
                  e.printStackTrace();
              }
              return connection;
          }
      
          //編寫查詢公共方法
          public static ResultSet execute(Connection connection,PreparedStatement preparedStatement, ResultSet resultSet,String sql, Object[] params) throws SQLException {
              //預編譯的sql,在后面直接執行就可以了
              preparedStatement = connection.prepareStatement(sql);
      
              for (int i = 0; i < params.length; i++) {
                  //setObject,占位符從1開始,但是我們的數據是從0開始!
                  preparedStatement.setObject(i + 1, params[i]);
      
              }
              preparedStatement.executeQuery();
              return resultSet;
          }
      
          //編寫增刪改的公共方法
          public static int execute(Connection connection,PreparedStatement preparedStatement, String sql, Object[] params) throws SQLException {
              preparedStatement = connection.prepareStatement(sql);
      
              for (int i = 0; i < params.length; i++) {
                  //setObject,占位符從1開始,但是我們的數據是從0開始!
                  preparedStatement.setObject(i + 1, params[i]);
      
              }
              int updateRows = preparedStatement.executeUpdate();
              return updateRows;
          }
      
          //釋放資源
          public static boolean closeResource(ResultSet resultSet, PreparedStatement preparedStatement, Connection connection) {
              boolean flag = true;
      
              if (resultSet != null) {
                  try {
                      resultSet.close();
                      //GC回收
                      resultSet = null;
                  } catch (SQLException throwables) {
                      throwables.printStackTrace();
                      flag = false; //相當於沒有釋放成功
                  }
              }
      
              if (preparedStatement != null) {
                  try {
                      preparedStatement.close();
                      //GC回收
                      preparedStatement = null;
                  } catch (SQLException throwables) {
                      throwables.printStackTrace();
                      flag = false; //相當於沒有釋放成功
                  }
              }
      
              if (connection != null) {
                  try {
                      connection.close();
                      //GC回收
                      connection = null;
                  } catch (SQLException throwables) {
                      throwables.printStackTrace();
                      flag = false; //相當於沒有釋放成功
                  }
              }
              return flag;
          }
      }
      

   3. 編寫字符編碼過濾器

      public class CharacterEncodingFilter implements Filter {
          public void init(FilterConfig filterConfig) throws ServletException {
      
          }
      
          public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
              request.setCharacterEncoding("utf-8");
              response.setCharacterEncoding("utf-8");
              response.setContentType("text/html; charset=UTF-8");
      
              chain.doFilter(request, response);
          }
      
          public void destroy() {
      
          }
      }
      

      配置字符編碼過濾器的web.xml

          <!--字符編碼過濾器-->
          <filter>
              <filter-name>CharacterEncodingFilter</filter-name>
              <filter-class>com.tan.filter.CharacterEncodingFilter</filter-class>
          </filter>
          <filter-mapping>
              <filter-name>CharacterEncodingFilter</filter-name>
              <url-pattern>/*</url-pattern>
          </filter-mapping>
      

8. 導入靜態資源
   

登錄功能實現

1. 編寫前端頁面

2. 設置首頁

      <!--設置歡迎頁面-->
       <welcome-file-list>
           <welcome-file>login.jsp</welcome-file>
       </welcome-file-list>
   

3. 編寫dao層用戶登錄的登錄接口

   public interface UserDao  {
   
       /*得到要登錄的用戶*/
       public User getLoginUser(Connection connection, String userCode) throws SQLException;
   }
   

4. 編寫dao接口的實現類

   public class UserDaoImpl implements UserDao {
   
       PreparedStatement pstm = null;
       ResultSet rs = null;
       User user = null;
   
       public User getLoginUser(Connection connection, String userCode) throws SQLException {
   
           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("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(connection, pstm,rs);
   
           }
   
           return user;
       }
   }
   

5. 業務層接口

   public interface UserService {
       //用戶登錄
       public User login(String userCode, String password);
   }
   

6. 業務層接口實現類

public class UserServiceImpl implements UserService {

    //業務層都會調dao層,所以我們要引入Dao層
    private UserDao userDao;

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

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

        try {
            connection = BaseDao.getConnection();
            //通過業務層調用對應的具體的數據庫操作
            user = userDao.getLoginUser(connection, userCode);

        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            BaseDao.closeResource(connection, null, null);
        }
        return user;
    }

}

7. 編寫Servlet

   public class LoginServlet extends HttpServlet {
       @Override
       protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
           System.out.println("LoginServlet----start.....");
   
           //獲取用戶的賬號密碼
           String userCode = req.getParameter("userCode");
           String userPassword = req.getParameter("userPassword");
   
           //和數據庫的密碼進行對比,調用業務層
           UserService userService = new UserServiceImpl();
           User user = userService.login(userCode, userPassword);
           if (user != null && userPassword.equals(user.getUserPassword())) {//查到有人可以登錄,與數據庫的密碼進行對比
               //將用戶的信息放到Session中
               req.getSession().setAttribute(Constants.USER_SESSION,user);
               //跳到內部主頁
               resp.sendRedirect("jsp/frame.jsp");
           }else {//查無此人,無法登錄
               //轉發回登陸頁面,順帶提示用戶名或密碼錯誤
               req.setAttribute("error","用戶名或者密碼不正確");
               req.getRequestDispatcher("login.jsp").forward(req, resp);
           }
   
       }
   
       @Override
       protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
           doGet(req, resp);
       }
   }
   

8. 注冊Servlet

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

9. 測試訪問,確保以上功能成功!

登錄功能優化

注銷功能:

思路: 移除session,返回登陸界面

public class LogoutServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //移除用戶的Constants.USER_SESSION
        req.getSession().removeAttribute(Constants.USER_SESSION);
        resp.sendRedirect("/login.jsp");//返回登陸頁面
    }

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

注冊xml

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

登錄攔截優化

退出后仍可以直接進入,過濾器優化

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;

        //從Session中獲取用戶
        User user = (User) request.getSession().getAttribute(Constants.USER_SESSION);

        if (user == null) {//已被移除注銷,或者登錄
            response.sendRedirect("/smbms/error.jsp");
        }else {
            chain.doFilter(req, resp);
        }
    }

    @Override
    public void destroy() {

    }
}

配置xml

    <!--登錄優化過濾器-->
    <filter>
        <filter-name>SysFilter</filter-name>
        <filter-class>com.tan.filter.SysFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>SysFilter</filter-name>
        <url-pattern>/jsp/*</url-pattern>
    </filter-mapping>

測試,登錄,注銷,權限,都要保證OK!

密碼修改

1. 導入前端素材

   <li><a href="${pageContext.request.contextPath }/jsp/pwdmodify.jsp">密碼修改</a></li>
   

2. 寫項目,建議從底層向上寫
   

3. UserDao 接口

   //修改當前用戶密碼
   public int updatePwd(Connection connection, int id, String password) throws SQLException;
   

4. UserDao 接口實現類

       @Override
       //修改當前用戶密碼
       public int updatePwd(Connection connection, int id, String password) throws SQLException {
           PreparedStatement pstm = null;
           int execute = 0;
   
           if(connection!=null){
               Object params[] = {password, id};
               String sql = "update smbms_user set userPassword = ? where id = ?";
               execute = BaseDao.execute(null, pstm, sql, params);
               BaseDao.closeResource(null, pstm, null);
           }
   
           return execute;
       }
   }
   

5. UserService層

   //根據用戶ID修改密碼
   public boolean updatePwd(int id, String pwd);
   

6. UserService層實現類

       @Override
       public boolean updatePwd(int id, String pwd) {
           Connection connection = null;
           boolean flag = false;
   
           connection = BaseDao.getConnection();
           //修改密碼
           try {
               if (userDao.updatePwd(connection, id, pwd)>0) {
                   flag = true;
               }
           } catch (SQLException throwables) {
               throwables.printStackTrace();
           }finally {
               BaseDao.closeResource(connection, null, null);
           }
           return flag;
       }
   

7. 記得實現復用,需要提取出方法

   String method = req.getParameter("method");
   if (method.equals("savepwd") && method != null) {
       this.updatePwd(req,resp);
   }
   

   提取出的方法:

       //寫成方法實現Servlet的復用
       public void updatePwd (HttpServletRequest req, HttpServletResponse resp){
           //從Session里面拿ID
           Object o = req.getSession().getAttribute(Constants.USER_SESSION);
           String newpassword = req.getParameter("newpassword");
   
           boolean flag = false;
   
           if (o != null && newpassword != null && newpassword.length() != 0) {
               UserServiceImpl userService = new UserServiceImpl();
               flag = userService.updatePwd(((User) o).getId(), newpassword);
               if (flag) {
                   req.setAttribute("message", "修改密碼成功,請退出重新登陸.");
                   //密碼修改成功,移除當前Session
                   req.getSession().removeAttribute(Constants.USER_SESSION);
               } else {
                   req.setAttribute("message", "密碼修改失敗");
               }
           } else {
               req.setAttribute("message", "新密碼有問題");
           }
           try {
               req.getRequestDispatcher("pwdmodify.jsp").forward(req, resp);
           } catch (ServletException | IOException e) {
               e.printStackTrace();
           }
       }
   }
   

   記配置web.xml

8. 測試

優化密碼修改使用Ajax

1. 阿里巴巴fastjson

     <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
           <dependency>
               <groupId>com.alibaba</groupId>
               <artifactId>fastjson</artifactId>
               <version>1.2.62</version>
           </dependency>
   

2. 后台代碼修改

//驗證舊密碼
public void pwdModify(HttpServletRequest req, HttpServletResponse resp) {
    //從Session里面拿ID
    Object o = req.getSession().getAttribute(Constants.USER_SESSION);
    String oldpassword = req.getParameter("oldpassword");//獲取從pwdmodify.js里Ajax的參數,連接前端

    //萬能的Map : 結果集
    HashMap<String, String> resultMap = new HashMap<>();

    if (o == null) {//Session過期或者失效了
        resultMap.put("result", "sessionerror");
    } else if (StringUtils.isNullOrEmpty(oldpassword)) {//輸入的密碼為空
        resultMap.put("result", "false");
    } else {
        String userPassword = ((User) o).getUserPassword();//Session中獲取用戶的老密碼
        if (oldpassword.equals(userPassword)) {
            resultMap.put("result", "true");//輸入密碼正確
        } else {
            resultMap.put("result", "true");//輸入密碼輸入不正確
        }
    }

    try {
        resp.setContentType("application/json");//限定為json格式
        PrintWriter writer = resp.getWriter();//給個流
        //使用阿里巴巴JSON工具類
        /*
        將Map格式轉化為JSON格式
        */
        writer.write(JSONArray.toJSONString(resultMap));
        writer.flush();
        writer.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

3. 調試

用戶管理實現(實在是太多,放棄做筆記了)

思路:

1. 導入分頁的工具類
2. 用戶列表頁面導入

1.獲取用戶數量

1. UserDao
2. UserDaoImpl
3. UserService
4. UserServiceImpl