no data when run my webapp

**Eclectica** · May 13th, 2012, 05:42 AM

Hi,

I'm trying to create a HotelBooking application in SpringMVC.

I create a database in MySQL named: dbHotels with a table: tblhotels with a few columns (name,address,...)

In Eclipse I create a Config.java, HotelController.java, HotelDAO.java, HotelDAOcoll.java and a Hotel.java for my modelling

In my Home.jsp I want to list all the hotels, For this moment I have one record in my table (tblhotels)

When I try to run the webapp I see nothing ...

This is my code for my Home.jsp, I dont know what to write in my value, I'm not sure its hotel.name

Code:

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <h1 style="color:red">Welcome on hotels.com!</h1>
        <p>test</p>
        <c:out value="${hotel.name}"/>		
    </body>
</html>

In my HotelDAOColl i have this code

Code:

package eu.hotel.dao;
import eu.hotel.example.model.Hotel;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

import org.springframework.stereotype.Repository;



@Repository
public class HotelDAOcoll implements HotelDAO{
	@PersistenceContext
	private EntityManager entityManager;
	
	@SuppressWarnings("unchecked")
	public List<Hotel> findAll(){
		
		Query query = entityManager.createQuery("select h.name from Hotel h");
		return query.getResultList();
		
	}
}

Thnx!

**pgrimard** · May 13th, 2012, 06:20 AM

Could you post your @Controller class? Are you adding the result of findAll() as a model attribute when handling the request from the client?

**Eclectica** · May 13th, 2012, 07:13 AM

hi pgrimard, this is my controller class

Code:

package eu.hotel.example.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;

import eu.hotel.example.dao.HotelDAO;
import eu.hotel.example.dao.ReservationDAO;
import eu.hotel.example.model.Reservation;

@Controller
public class HotelController {
	@Autowired
	private HotelDAO hoteldao;
	@Autowired
	private ReservationDAO reservationdao;
		
		
	@RequestMapping("/")
	public String getHotels(Model model) {
		model.addAttribute("Hotel", hoteldao.findAll());
		Reservation reservation = new Reservation();
		//model.addAttribute("tblreservations", reservation);
		return "home";
	}
}

In mij HotelDAO I have my findall

Code:

package eu.hotel.example.dao;

import java.util.List;
import eu.hotel.example.model.Hotel;

public interface HotelDAO {
	List<Hotel> findAll();
}

**pgrimard** · May 13th, 2012, 07:46 AM

Well I see 2 potential problems.

First is that findAll() will return a List or collection of Hotels, but in your view, you're not iterating over the collection. You're just attempting to access the name property of the "hotel" attribute. The "hotel" attribute is a collection, so the name property doesn't exist.

Secondly, I think model attributes are case sensitive. In your controller, you're adding a model attribute as "Hotel", but in your view you're referencing a model attribute named "hotel".

**Eclectica** · May 13th, 2012, 09:31 AM

Thnx for your reply
I changed some code in my view but it still doesnt work :-( :

Code:

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <h1 style="color:red">Welcome on hotels.com!</h1>
        <p>test</p>
        <c:forEach var="hotel" items="${Hotel}">
			<tr>
				<td>${hotel.name}</td>
			</tr>
		</c:forEach>
    </body>
</html>

**pgrimard** · May 13th, 2012, 10:35 AM

Well your view looks ok now, aside from not wrapping your <c:forEach> with a <table>.

If we break things down to their basic elements, could you create a quick unit test to make sure that your findAll() method actually returns data?

Besides that, I noticed in your first post that your view's file name is Home.jsp. I think view names are case sensitive too, so since you're returning "home" in your handler mapping, maybe it's not even loading the correct view. Are you able to confirm that?

Btw, are there any exceptions being thrown when you browse to your page?

**Eclectica** · May 13th, 2012, 02:53 PM

Hi,

How can I create a unit test in Eclipse?
If I run my project I see my Home.jsp so thats not a problem
I see my Welcome screen but no data...

**pgrimard** · May 14th, 2012, 07:01 AM

Creating a unit test is pretty simple. You just have to make sure you using your Spring configuration to inject the Hotel repository. In the example below, the @ContextConfiguration is where you specify the location of your Spring configuration.

So you might have something like this. If this unit test passes, then your DAO is indeed returning data and you should see the name of each hotel in the system console.

Code:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:/META-INF/spring/applicationContext.xml" })
public class TestHotelRepository {
	
	@Autowired
	private HotelDAO hotelDao;
	
	@Test
	public void list() {
		List<Hotel> hotels = hodelDao.findAll();
		
		Assert.assertTrue(hotels.size() > 0);
		
		for(Hotel hotel : hotels) {
			System.out.println(hotel.getName());
		}
	}
}

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