Para conectar a una base de datos necesitamos un driver, que es un fichero que debe estar en el path del proyecto en /WEB-INF/lib.

contex.xml

<Context>
  <resource  name="jdbc/dad2" auth="Container" type="javax.sql.DataSource" <!--Name: TipoDeRecurso/NombreAsignado-->
  maxActive="50" maxIdle ="30"naxWait="10000"
  username="root" password=""
  driverClassName="com.mysql.jdbc.Driver"
  uri="jdbc.mysql://localhost:3306/dad"/>
</Context>

Control.java

  public class Control extends HttpServlet{
    private static final long serialVersionUID = 1L;
    public static final String PRM_ACCION = "PRM_ACCION_CONTROL";
 
    private Hashtable<String, Accion> hashAcciones=null;
    private static Factory factory = null;
 
    public void init() throws ServletException{
      system.out.println("Iniciando...");
      PrepareStatement ps = null;
      resultSet rs = null;
      try{
        Connection con = Control.ds.getConnection();
        ps = con.prepareStatement ("SELECT * FROM ACTIONS");
        rs = ps.executeQuery;
 
        Action Accion = null;
        this.hashAcciones = new Hashtable<String, Accion>();
        while(rs.next()){
          accion = (Accion)Class.forName(rs.getString("class")).newInstance();
          String id = res.getString("id");
          System.out.println(id + "" + accion);
          this.hashAcciones.put(id, accion);
        }
 
      }catch(SQLException e){
        System.out.println("error" + e.toString());
      }
    }
  }