fix invalid string access, related #i83611#
fix invalid string access, related #i83611#

Change-Id: I5954f78e10d99a064f83e96282c28c086c7f07f1

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core