使用el表达式,在显示的地方进行表示,前端代码如下:
<div class="shortcut">
<div class="login_out">
<c:if test="${empty user}">
<a href="login.jsp">登录</a>
<a href="register.jsp">注册</a>
</c:if>
<c:if test="${!empty user }">
<a href="#">欢迎回来${user.username}</a>
<a href="#">退出</a>
</c:if>
</div>
</div>
在注册的后端代码将user对象保存在session域中,代码如下:
@RequestMapping(value = "/loginUser")
public void loginUser(User user,HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.验证校验码
String check = request.getParameter("check");
String check_code = (String) request.getSession().getAttribute("CHECKCODE_SERVER");
if(!check.equals(check_code)) {
response.sendRedirect("error/LoginCode.jsp");
return;
}
System.out.println(user);
//封装成User对象
//2.根据用户名查找用户是否存在
User user1 = userService.getUserByUsernameAndPasswordService(user);
//用户不存在
if(user1 == null) {
response.sendRedirect("error/NullUser.jsp");
return;
}
//将用户保存在session域中
request.getSession().setAttribute("user",user1);
request.getRequestDispatcher("index.jsp").forward(request,response);
}