HTTP Status 500:The server encountered an unexpected condition that prevented it from fulfilling the request.

Não consigo acessar as URLs: http://localhost:8080/casadocodigo/produtos http://localhost:8080/casadocodigo/produtos/form

retornando sempre um Status 500

HTTP Status 500 – Internal Server Error

Type Exception Report

Message Request processing failed; nested exception is org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Could not open connection

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Could not open connection
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:973)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
Root Cause

package br.com.casadocodigo.loja.daos;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import br.com.casadocodigo.loja.models.Produto;

@Repository
@Transactional
public class ProdutoDao {

    @PersistenceContext
    private EntityManager manager;

    public void gravar(Produto produto) {
        manager.persist(produto);
    }

    public List<Produto> listar() {
        return manager.createQuery("Select p from Produto p", Produto.class).getResultList();
    }
}

package br.com.casadocodigo.loja.controllers;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import br.com.casadocodigo.loja.daos.ProdutoDao;
import br.com.casadocodigo.loja.models.Produto;
import br.com.casadocodigo.loja.models.TipoPreco;

@Controller
@RequestMapping("/produtos")
public class ProdutosController {

    @Autowired
    private ProdutoDao dao;

    @RequestMapping("/form")
    public ModelAndView form() {

        ModelAndView modelAndView = new ModelAndView("produtos/form");
        modelAndView.addObject("tipos", TipoPreco.values());

        return modelAndView;

    }

    @RequestMapping(method=RequestMethod.POST)
    public String grava(Produto produto) {

        dao.gravar(produto);

        return "produtos/ok";
    }

    @RequestMapping(method=RequestMethod.GET)
    public ModelAndView listar() {
        ModelAndView modelAndView = new ModelAndView("produtos/lista");
        List<Produto> produtos = dao.listar();
        modelAndView.addObject("produtos", produtos);

        return modelAndView;
    }
}

package br.com.casadocodigo.loja.conf;

import javax.servlet.Filter;

import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class ServletSpringMVC extends AbstractAnnotationConfigDispatcherServletInitializer{

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return null;
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[] { AppWebConfiguration.class , JPAConfiguration.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[] {"/"};
    }

    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter();
        encodingFilter.setEncoding("UTF-8");
        return new Filter[] {encodingFilter};
    }

}