Could Integer encoding ignore the empty value?

[Yiming Liu]

Hi Kylin devs,

Currently, if some dimension is marked as Integer encoding, but there is
empty value(NULL and "" ) in that column, Kylin will report
NumberFormatException.

IntegerDimEnc Line 92, Long.parseLong()

Could we add some check before the parsing?

-- 
With Warm regards

Yiming Liu (刘一鸣)