p:dataExporter does not recognize p:cellEditor

The <p:cellEditor> is indeed not recognized by the PrimeFaces standard data exporters.
I’ve previously reported this to the PF guys as issue 4013 with an example which not only mentions CellEditor, but also HtmlGraphicImage (we are using images to show boolean states, whose alt we’d like to show in PDF/XML/XLS/CSV reports).

First, create a new class which extends the standard PDFExporter like follows:

public class ExtendedPDFExporter extends PDFExporter {

    @Override
    protected String exportValue(FacesContext context, UIComponent component) {
        if (component instanceof CellEditor) {
            return exportValue(context, ((CellEditor) component).getFacet("output"));
        }
        else if (component instanceof HtmlGraphicImage) {
            return (String) component.getAttributes().get("alt");
        }
        else {
            return super.exportValue(context, component);
        }
    }

}

Then, to use it, call it programmatically instead of via <p:dataExporter>.

<p:dataTable binding="#{table}" editable="true" ...>
    <p:column><p:cellEditor>...</p:cellEditor></p:column>
    <p:column><p:cellEditor>...</p:cellEditor></p:column>
    <p:column><p:cellEditor>...</p:cellEditor></p:column>
    <p:column exportable="false"><p:rowEditor /></p:column>
</p:dataTable>
<h:commandLink value="PDF" action="#{bean.exportPDF(table, 'filename')}" />

With

public void exportPDF(DataTable table, String filename) throws IOException {
    FacesContext context = FacesContext.getCurrentInstance();
    Exporter exporter = new ExtendedPDFExporter();
    exporter.export(context, table, filename, false, false, "UTF-8", null, null);
    context.responseComplete();
}

Feel free to find the data table by UIComponent#findComponent() instead and to set the filename in action method only. The above code is just exemplary.