￥と／の関連性（windowsとlinux)

File.separator;

■Linux
filenamenew = filenamenew.replace("￥￥", "/") + "/list.xls";
■Windows
filenamenew = filenamenew.replace("￥￥", "￥￥") + "￥￥list.xls";

※「￥」は小文字の円マーク