Get messy code while fecthing ftp sites

[fangky]

I meet a very strange problem,my nutch8.1 can crawl http sites normally but 
while fetching ftp sites, it got messy code.

for example, in the root diretory of an ftp site, there is a subdiretory named 
in chinese"教学资源中心", a normal crawl result should be 
index of /教学资源中心
but when nutch fetch it, it become 
Index of /???¡ì¡Á???????/ 
this problem not apeared while feching diretories named in english.

can anyone tell me how to do ?

thanks in advance.