登录功能

登录功能分析

 

 

 

代码实现

 

 LoginServlet类：

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取验证码
        String check = request.getParameter("check");
        //从session中获取验证码
        HttpSession session = request.getSession();
        String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER");
        //保证验证码只能使用一次
        session.removeAttribute("CHECKCODE_SERVER");
        //判断
        if (checkcode_server == null && !checkcode_server.equalsIgnoreCase(check)){
            //验证码错误
            ResultInfo info = new ResultInfo();
            info.setFlag(false);
            info.setErrorMsg("验证码错误");
            //将info对象序列化为json
            ObjectMapper mapper = new ObjectMapper();
            String json = mapper.writeValueAsString(info);
            response.setContentType("application/json;charset=utf-8");
            response.getWriter().write(json);
            return;
        }


        //1、获取用户名和密码数据
        Map<String, String[]> map = request.getParameterMap();
        //2、封装User对象
        User user = new User();
        try {
            BeanUtils.populate(user,map);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        //3、调用Service查询
        UserService service = new UserServiceImpl();
        User u = service.login(user);
　　　　 session.setAttribute("user",u);
        ResultInfo info = new ResultInfo();
        //4、判断用户对象是否存在
        if(u==null){
            //用户名密码错误
            info.setFlag(false);
            info.setErrorMsg("用户名或密码错误");
        }
        //5、判断用户是否激活
        if(u != null && !"Y".equals(u.getStatus())){
            //用户尚未激活
            info.setFlag(false);
            info.setErrorMsg("您尚未激活，请激活");
        }
        //6、判断登录成功
        if (u!=null && "Y".equals(u.getStatus())){
            info.setFlag(true);
        }

        //响应数据
        ObjectMapper mapper = new ObjectMapper();
        response.setContentType("application/json;charset=utf-8");
        mapper.writeValue(response.getOutputStream(),info);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}

UserService接口：

User login(User user);

UserServiceImpl实现类：

/**
     * 登录方法
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findByUsernameAndPassword(user.getUsername(),user.getPassword());
    }

UserDao接口：

User findByUsernameAndPassword(String username, String password);

UserDaoImpl实现类：

@Override
    public User findByUsernameAndPassword(String username, String password) {
        User user = null;
        try {
            //定义sql
            String sql = "select * from tab_user where username = ? and password = ?";
            //执行sql
            user = template.queryForObject(sql,new BeanPropertyRowMapper<>(User.class),username,password);
        } catch (DataAccessException e) {

        }
        return user;
    }

 

 

登录前台页面

login.html页面：

<script>
        //1、给登录按钮绑定单击事件
        $(function () {
            $("#btn_sub").click(function () {
                //2、发送ajax请求，提交表单数据
                $.post("loginServlet",$("#loginForm").serialize(),function (data) {
                    //3、处理响应数据
                    if (data.flag){
                        //登录成功
                        location.href="index.html";
                    }else {
                        //登录失败
                        $("#errorMsg").html(data.errorMsg);
                    }
                });
            });
        });
    </script>

 

 

 

index页面中用户信息的姓名提示功能

姓名提示

FindUserServlet类：

@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //从session中获取登录用户
        Object user = request.getSession().getAttribute("user");
        //将user写回客户端

        ObjectMapper mapper = new ObjectMapper();
        response.setContentType("application/json;charset=utf-8");
        mapper.writeValue(response.getOutputStream(),user);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}

header.heml页面：

<script>
    $(function () {
        $.get("findUserServlet",{},function (data) {
            var msg = "欢迎回来,"+data.name;
            $("#span_username").html(msg);
        });
    });
</script>

 

 

 

 

退出登录

什么叫做登录了？session中有user对象

实现步骤：

　　1、访问servlet，将session销毁

　　2、跳转到登录页面

header.html页面：

<!-- 登录状态  -->
            <div class="login">
                
                <span id="span_username"></span>
                <a href="myfavorite.html" class="collection">我的收藏</a>
                <a href="javascript:location.href='exitServlet';">退出</a>
            </div>

ExitServlet类：

@WebServlet("/exitServlet")
public class ExitServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1、销毁session
        request.getSession().invalidate();

        //2、跳转登录页面
        response.sendRedirect(request.getContextPath()+"/login.html");
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}