@Override
  public List<MaterialBean> buscarMateriales(int codTipoMaterial, String descripcion)
      throws Exception {

    Connection cn = MySqlDbConn.obtenerConexion();
    CallableStatement st = cn.prepareCall("{ call pr_buscarMateriales(?, ?) }");
    st.setInt(1, codTipoMaterial);
    st.setString(2, descripcion);

    ResultSet rs = st.executeQuery();

    ArrayList<MaterialBean> arr = new ArrayList<MaterialBean>();

    while (rs.next()) {
      MaterialBean material = new MaterialBean();
      material.setStrCodMaterial(rs.getString("cod_mat"));
      material.setIntCodTipoMaterial(rs.getInt("cod_tip_mat"));
      material.setStrTipoMaterial(rs.getString("tip_mat"));
      material.setStrDescripMaterial(rs.getString("desc_mat"));
      material.setStrUnidadMedida(rs.getString("und_med_mat"));
      material.setBdPrecioUnitario(rs.getBigDecimal("prec_uni_mat"));
      arr.add(material);
    }
    rs.close();
    cn.close();
    return arr;
  }