Question

我有一个HTML页面，可以获得两个输入值，如下所示 LoginInfo类

<body> 
    <form method = "post" action = "LoginInfo"> 
        Login Id: <input type = "text" name = "name"/> <br> 
        Password: <input type = "password" name = "password"/> <br> <input type = "submit" value = "Login"/> 
    </form> 

</body>

我将这两个值传递给servelt页面，如下所示，

 @WebServlet(urlPatterns = "/LoginInfo")
 public class LoginInfo extends HttpServlet {

@Override
protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {
String name = request.getParameter("name");
return name;
}
}

并且servlet页面正在返回一些内容，我希望在表单下方的html页面中显示。现在我能够显示返回字符串，但表单消失了。我希望两个在同一个html页面中隐藏表单。谢谢！

Answer 1

首先，为什么要在doPost方法中放置一个返回值？因为它是你的代码不应该编译

@Override
protected void doPost(HttpServletRequest request,
    HttpServletResponse response) throws ServletException, IOException {
    String name = request.getParameter("name");

    return name; // why?? it's not needed
}

其次要将值从Servlet传递给Jsp，您必须创建一个属性，例如像这样的请求属性

 String name = request.getParameter("name");
 request.setAttribute("name", name);

然后，您必须使用请求dispacther

将请求转发回Jsp

RequestDispatcher disp = request.getRequestDispatcher();
disp.forward("nameofthepagewhereyourformis.jsp");

最后，您可以通过表达式语言检索Jsp中的属性。见下文

<body> 
   <form method = "post" action = "LoginInfo"> 
    Login Id: <input type = "text" name = "name"/> <br> 
    Password: <input type = "password" name = "password"/> <br> <input type = "submit" value = "Login"/> 
   </form> 

   $(name) // attribute set in the servlet. At the bottom of the form as you wanted
</body>

在相同的html页面中显示servlet响应而不隐藏表单

1 个答案: