@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
throws IOException, ServletException {
req.setCharacterEncoding("UTF-8");
res.setCharacterEncoding("UTF-8");
HttpServletRequest httpReq = (HttpServletRequest) req;
String lang = httpReq.getParameter("lang");
if (lang != null && !lang.isEmpty()) {
ThreadLocalLocaleHolder.set(new Locale(lang));
} else if ((lang = (String) httpReq.getSession().getAttribute("lang")) != null) {
ThreadLocalLocaleHolder.set(new Locale(lang));
}
httpReq.getSession().setAttribute("lang", ThreadLocalLocaleHolder.get().getLanguage());
chain.doFilter(req, res);
}