Java EE：从POST获取参数以获取登录表单 [英] Java EE: Getting parameters from POST for a login form

问题描述

我试图实现一个简单的登录servlet，但它无法正常工作。

我想知道的是是如何通过使用HTTP POST的参数。它已经与HTTP GET一起使用，但用户名和密码可以从URL中看到。

 < form method =postaction =home> 
< input name =usernameclass =form-logintitle =Usernamevalue =size =30maxlength =2048/> 
< input name =passwordtype =passwordclass =form-logintitle =Passwordvalue =size =30maxlength =2048/> 
< input type =submitvalue =连接> 
< / form> 
  

web.xml

 < servlet> 
< servlet-name>主页< / servlet-name> 
< servlet-class> controller.HomeController< / servlet-class> 
< / servlet> 
 
< servlet-mapping> 
< servlet-name>主页< / servlet-name> 
< url-pattern> / home< / url-pattern> 
< / servlet-mapping> 
  

Servlet：

 公共类HomeController扩展HttpServlet {
 
私有HttpSession会话; 
私人UserBean userBean; 
 
 public void doPost（HttpServletRequest请求，HttpServletResponse响应）
抛出ServletException，IOException {
 
 UserBean user = new UserBean（）; 
 String userName = request.getParameter（username）; 
 String password = request.getParameter（password）; 
 
 user.setUsername（userName）; 
 user.setPassword（password）; 
 
 user = UserDAO.login（user）; 
 
 dispatch（request，response，ApplicationRessource.getInstance（）。getHomePage（））; 
 
 
 protected void dispatch（HttpServletRequest请求，
 HttpServletResponse响应，String页面）
抛出javax.servlet.ServletException，java.io.IOException {
 RequestDispatcher dispatcher = getServletContext（）
 .getRequestDispatcher（page）; 
 dispatcher.forward（request，response）; 
 
 
 $ / code $ / pre 
 
 
问题在于 userName 和 password 字符串始终为空，这意味着永远不会从POST中获取参数。我做错了什么？
解决方案
它应该可以工作，您可以通过更改表单方法来获取并尝试检查，您应该看到参数在url中。
 
I am trying to implement a simple login servlet but it's not working properly.

What I wanted to know is how to pass the parameters using a HTTP POST. It already works with HTTP GET but the username and password are visible from the URL. It would be better to hide them in a POST.
<form method="post" action="home" >
  <input name="username" class="form-login" title="Username" value="" size="30" maxlength="2048" />
  <input name="password" type="password" class="form-login" title="Password" value="" size="30" maxlength="2048" />
  <input type="submit" value="Connect">
</form>
web.xml
  <servlet>
    <servlet-name>home</servlet-name>
    <servlet-class>controller.HomeController</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>home</servlet-name>
    <url-pattern>/home</url-pattern>
  </servlet-mapping>
Servlet:
public class HomeController extends HttpServlet {

    private HttpSession session;
    private UserBean userBean;

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        UserBean user = new UserBean();
        String userName = request.getParameter("username");
        String password = request.getParameter("password");

        user.setUsername(userName);
        user.setPassword(password);

        user = UserDAO.login(user);

        dispatch(request, response, ApplicationRessource.getInstance().getHomePage());
    }

    protected void dispatch(HttpServletRequest request,
                HttpServletResponse response, String page)
            throws javax.servlet.ServletException, java.io.IOException {
        RequestDispatcher dispatcher = getServletContext()
                .getRequestDispatcher(page);
        dispatcher.forward(request, response);
    }
}
The problem is that the userName and password strings are always empty, meaning that the parameters are never fetched from the POST. What am I doing wrong?
解决方案
it should work, can you check by changing form method to get and trying, you should see parameters in url.

                        
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