freemarker报错:Tip: If the failing expression is known to be legally null/missing, either specify a de
freemarker报错:Tip:Ifthefailingexpressionisknowntobelegallynull/missing,eitherspecifyadefaultvaluewithmyOptionalVar!myDefault,orusewhen-presentwhen-missing.(Theseonlycoverthelaststepoftheexpression;toco