Question

我已经使用JSP（account.jsp）创建了一个登录页面，如果登录成功，servlet会重定向到home.jsp，如果notstays /重定向到account.jsp。

如果登录失败，我将无法显示错误消息。因为我创建了一个设置为hidden.i.e的错误div。 style="display:none;"当登录出错时，我想将其显示设置更改为显示，即`style =＆＃34; display：block;＆＃34;

我想从servlet中做到这一点。有可能吗？如果是，怎么样？

登录表单

<div class="col-sm-4">
    <h3><STRONG>Login</STRONG></h3>
    <div id="login_alert" class="alert alert-danger" style="display:none;">
        <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
        <strong>Unsuccessful!</strong> Invalid Input
    </div>
    <form role="form" action="login" method="post">
        <div class="form-group">
            <input type="email" class="form-control" id="email" name="email" placeholder="Enter Email">
        </div>
        <div class="form-group">
            <input type="password" class="form-control" id="pwd" name="pwd" placeholder="Enter Password">
        </div>
        <div class="checkbox">
            <label><input type="checkbox"> Remember me</label>
        </div>
        <button id ="submit" type="submit" class="btn btn-success">Submit</button>
    </form>
</div>

Servlet代码

if(user exists){
    HttpSession session = request.getSession();
    session.setAttribute("user",user);
    session.setAttribute("pwd",pwd);
    request.getRequestDispatcher("./home.jsp").forward(request, response);
}else{
    //document.getElementById('login_alert').style.display='block';
    request.getRequestDispatcher("./account.jsp").forward(request, response);
}

Answer 1

1 - 添加请求属性

else{
    request.setAttribute("loginFailed",true);
    request.getRequestDispatcher("./account.jsp").forward(request, response);
}

2-在JSP中有条件地使用它

 <div id="login_alert" class="alert alert-danger" 

     style="display:${loginFailed ? 'block' : 'none'}" >

      <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>
      <strong>Unsuccessful!</strong> Invalid Input
 </div>

根据控制器结果有条件地修改css

1 个答案: