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登录功能实现

1. 登录页面login.jsp

2. 设置欢迎页

            
         
          login.jsp
         
        

   或者在index.jsp中写

3. dao

   public interface LoginDao {         //获取用户登录信息    public User getLogin(String userCode) throws SQLException;}

4. daoimpl

   public class LoginDaoImpl implements LoginDao {         @Override    public User getLogin(String uCode) throws SQLException {             Connection connection = null;        Connection conn = BaseDao.getConn();//立即建立连接        PreparedStatement preparedStatement = null;        ResultSet resultSet = null;        User user = null;        if (conn != null) {     //只有当连接不为mull，即数据库打开时，才能操作各种有关数据库的语句            String sql = "select * from smbms_user where userCode=?";            Object[] params = {     uCode};            resultSet = BaseDao.executeQ(conn, preparedStatement, resultSet, sql, params);            if (resultSet.next()) {                     int id = resultSet.getInt("id");                String userCode = resultSet.getString("userCode");                String userName = resultSet.getString("userName");                String userPassword = resultSet.getString("userPassword");                int gender = resultSet.getInt("gender");                Date birthday = resultSet.getDate("birthday");                String phone = resultSet.getString("phone");                String address = resultSet.getString("address");                int userRole = resultSet.getInt("userRole");                int createdBy = resultSet.getInt("createdBy");                Date creationDate = resultSet.getDate("creationDate");                int modifyBy = resultSet.getInt("modifyBy");                Date modifyDate = resultSet.getDate("modifyDate");                int age = resultSet.getInt("age");                String userRoleName = resultSet.getString("userRoleName");                user = new User(id, userCode, userName, userPassword, gender, birthday, phone, address, userRole, createdBy, creationDate, modifyBy, modifyDate, age, userRoleName);            }            BaseDao.close(null, preparedStatement, resultSet);        }    return user;    }}

5. service

   public interface LoginService {         //登录业务处理    public User login(String uCode,String uPassword) throws SQLException;}

6. serviceimpl

   public class LoginServiceImpl implements LoginService {     //    private LoginDao loginDao;//    LoginServiceImpl(){     //        loginDao = new LoginDaoImpl();//    }    @Override    public User login(String uCode, String uPassword) throws SQLException {             LoginDao loginDao = new LoginDaoImpl();        User user = loginDao.getLogin(uCode);        return user;    }}

7. servlet

   @WebServlet("/login.do")public class LoginServlet extends HttpServlet {      @Override    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {             String userCode = req.getParameter("userCode");        String password = req.getParameter("userPassword");        LoginService loginService = new LoginServiceImpl();        try {                 User user = loginService.login(userCode, password);            if (user != null){                     HttpSession session = req.getSession();                session.setAttribute(Constants.USER_SESSION, user);                resp.sendRedirect("jsp/frame.jsp");            }else {                     req.setAttribute("error", "用户名或密码错误");                req.getRequestDispatcher("login.jsp").forward(req, resp);            }        } catch (SQLException e) {                 e.printStackTrace();        }    }}

登录功能优化

实现注销：移除session，返回登录

//注销就是移除session@WebServlet("/user/exit.do")public class LogoutServlet extends HttpServlet {       @Override    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {           //创建session        HttpSession session = req.getSession();        //移除session        session.removeAttribute(Constants.USER_SESSION);        resp.sendRedirect("/login.jsp");    }}

登录拦截优化

编写filter

//拦截  未登录不能直接进入主页@WebFilter("/jsp/*")public class SysFilter implements Filter {       @Override    public void init(FilterConfig filterConfig) throws ServletException {       }    @Override    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {           HttpServletRequest request = (HttpServletRequest) servletRequest;        HttpServletResponse response = (HttpServletResponse) servletResponse;        HttpSession session = request.getSession();        User user_sess = (User) session.getAttribute(Constants.USER_SESSION);        if (user_sess == null){               request.getRequestDispatcher("/error.jsp").forward(request, response);        }else {               filterChain.doFilter(servletRequest, servletResponse);        }    }    @Override    public void destroy() {       }}

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