converting html entity to utf-8 character

I am having this problems in grails where I am writing a string from the datab开发者_如何学运维ase into an xml file using StreamingMarkUpBuilder. The xml file displays the string as htmlentities &#x30b3 &#x30d4 &#x30fc, how can I convert them to be printed as コピー?

Thanks!

I found a solution for this, I used OutputStreamWriter instead of FileWriter to enfored encoding to UTF-8