有关JSP，Servlet和MongoDB Mlab的问题

如何解决有关JSP，Servlet和MongoDB Mlab的问题

我是MongoDB Mlab的新手，这意味着不熟悉如何使用它以及如何将其与DAO文件连接。我在SERVLET上遇到一个技术问题。首先，我尝试从MongoDB mlab提取数据，以获取登录页面用户的电子邮件和密码。而且，我还使用“ request.getParameter（“”）“方法捕获了用户在登录JSP页面上输入的电子邮件和密码。这两点工作正常，因为我已经对其进行了测试。关于我的问题的更多信息是，当我尝试从MongoDB mlab提取电子邮件和密码时，我将这两个参数存储到用户对象中，并将用户对象存储到ArrayList中。然后将此Arraylist返回到登录Servlet。使用for-each循环遍历此列表。我将代码放在下面。

When I try to enter an email and password on the login page,this is the result I encountered 我该怎么解决

FDao.java

package Dao;

import static com.sun.corba.se.spi.presentation.rmi.StubAdapter.request;
import java.net.UnknownHostException;
import java.sql.*;
import java.util.*;
import javax.servlet.RequestDispatcher;
import model.Book;
import model.Staff;
import model.User;
import org.bson.Document;

public class FDao {

    public List<User> checkLogin() throws UnknownHostException {
        
        Iterator it = DB.getDB().getCollection("users").find().iterator();
        List<User> aUser = new ArrayList();
        while(it.hasNext()){
            Document o = (Document) it.next();
            aUser.add(new User(o.getString("email"),o.getString("password")));
        }
        return aUser;
    }
    
}

LoginServlet.java（我从登录JSP页面捕获字符串电子邮件和字符串密码）

@WebServlet("/Login")
public class LoginServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;
    public LoginServlet() {
        super();
    }
    FDao userDao = new FDao();

    @Override
    protected void doPost(HttpServletRequest request,HttpServletResponse response)
            throws ServletException,IOException {
        response.setContentType("text/html");

        String email = request.getParameter("email");
        String password = request.getParameter("pass");
        List<User> users = new ArrayList();
        users = userDao.checkLogin();
        
        for (User user : users) {
            if (email.equals(user.getEmail()) && password.equals(user.getPassword()) ) {
                //HttpSession session = request.getSession();
                //session.setAttribute("user",user); 
                request.getRequestDispatcher("/home.jsp").include(request,response); //the problem looks like appeared in this line of code
                //out.println("Hello World");
            } else {
                //String message = "Your account does not exist in out database!";
                //request.setAttribute("message",message); //message is object
                request.getRequestDispatcher("/Login.jsp").include(request,response);//the problem looks like appeared in this line of code
                //out.println("Nothing");
            }
            break;
        }

        
    }
}