springMVCは先端にlistを伝えます.

Controller            

List categoryIds =new ArrayList<>();

List caterotyList =promotionThemeVO.getCategoryRelationList();
 categoryIds =CommonUtil.getValueList(caterotyList,"relationId");

request.setAttribute("cIds",JsonUtils.toJson(categoryIds));

        

var categoryIds =${cIds};

js    
var categoryCache={},editCategoryIdsJ={};;
if(categoryIds && categoryIds.length>0){
   for(var i=0;i