SMBMS项目(登陆注销)

数据库：

项目如何搭建？

考虑使用不使用Maven？ 依赖，Jar

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. 导入项目中会遇到的jar包；

   jsp,Servlet,mysql驱动，jstl，stand…

5. 创建项目包结构

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

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

   2. 编写数据库的公共类

      package com.kuang.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;
          }
      
          //编写查询公共方法
          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
              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;
          }
      
      
          //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;
          }
      
      }
      
      

   3. 编写字符编码过滤器

8. 导入静态资源

登录功能实现

1. 编写前端页面
2. 设置首页

      
       <welcome-file-list>
           <welcome-file>login.jspwelcome-file>
       welcome-file-list>
   

3. 编写dao层登录用户登录的接口

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

4. 编写dao接口的实现类

   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

   public interface UserService {
       //用户登录
       public User login(String userCode,String password);
   }
   

6. 业务层实现类

 public class UserServiceImpl implements UserService {
 
     //业务层都会调用dao层，所以我们要引入Dao层；
     private UserDao userDao;
     public UserServiceImpl(){
         userDao = new UserDaoImpl();
     }
 
 
     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 e) {
             e.printStackTrace();
         }finally {
             BaseDao.closeResource(connection,null,null);
         }
         return user;
     }
 
 }

7. 编写Servlet

   package com.kuang.servlet.user;
   
   import com.kuang.pojo.User;
   import com.kuang.service.user.UserService;
   import com.kuang.service.user.UserServiceImpl;
   import com.kuang.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；
           UserService userService = new UserServiceImpl();
           User user = userService.login(userCode, userPassword);  //这里已经把登录的人给查出来了
   
           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，无法登录
               //转发回登录页面，顺带提示它，用户名或者密码错误；
               req.setAttribute("error","用户名或者密码不正确");
               req.getRequestDispatcher("login.jsp").forward(req,resp);
           }
   
   
       }
   
       @Override
       protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
           doGet(req, resp);
       }
   }
   
   

8. 注册Servlet

   
   <servlet>
       <servlet-name>LoginServletservlet-name>
       <servlet-class>com.kuang.servlet.user.LoginServletservlet-class>
   servlet>
   <servlet-mapping>
       <servlet-name>LoginServletservlet-name>
       <url-pattern>/login.dourl-pattern>
   servlet-mapping>
   

9. 测试访问，确保以上功能成功！

登录功能优化

注销功能：

思路：移除Session，返回登录页面

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

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

注册xml

    <servlet>
        <servlet-name>LogoutServletservlet-name>
        <servlet-class>com.kuang.servlet.user.LogoutServletservlet-class>
    servlet>
    <servlet-mapping>
        <servlet-name>LogoutServletservlet-name>
        <url-pattern>/jsp/logout.dourl-pattern>
    servlet-mapping>

登录拦截优化

编写一个过滤器，并注册

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;

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

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

    public void destroy() {

    }
}

    
    <filter>
        <filter-name>SysFilterfilter-name>
        <filter-class>com.kuang.filter.SysFilterfilter-class>
    filter>
    <filter-mapping>
        <filter-name>SysFilterfilter-name>
        <url-pattern>/jsp/*url-pattern>
    filter-mapping>

测试，登录，注销，权限，都要保证OK！