class CarrinhoCompraBean {
  public List<Item> getItems {
    List<Item> items = consultaBanco(idCarrinho);
    return items;
  }
  public static class Item {
    // ...
  }
}

<h:dataTable id="table1" value="#{carrinhoCompraBean.items}" var="item" >
    <h:column>
        <f:facet name="header">
            <h:outputText value="Item" />
        </f:facet>
        <h:outputText value="#{item.nome}" />
    </h:column>
    <h:column>
        <f:facet name="header">
            <h:outputText value="Preço" />
        </f:facet>
        <h:outputText value="#{item.preco}" />
    </h:column>
</h:dataTable>