servlet filter

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // TODO Auto-generated method stub
        // place your code here
        String targetEncoding = "UTF-8";
        String encoding = request.getCharacterEncoding();
        System.out.println(encoding);
        if (encoding != null && !encoding.equalsIgnoreCase(targetEncoding)) {
            response.setCharacterEncoding(targetEncoding);
        }
        // pass the request along the filter chain
        chain.doFilter(request, response);
    }

encoding = request.getCharacterEncoding();

if (targetEncoding.equalsIgnoreCase(encoding)){
    // ...
}

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest wrapRequest = (HttpServletRequest)request;
        HttpServletResponse wrapResponse = (HttpServletResponse)response;
        String targetEncoding = "UTF-8";
        String inEncoding = wrapRequest.getCharacterEncoding();
        String outEncoding = wrapResponse.getCharacterEncoding();
        if (inEncoding == null || !inEncoding.equalsIgnoreCase(targetEncoding)) {
            wrapRequest.setCharacterEncoding(targetEncoding);
        }
        if (outEncoding == null || !outEncoding.equalsIgnoreCase(targetEncoding)) {
            wrapResponse.setCharacterEncoding(targetEncoding);
        }
        chain.doFilter(wrapRequest, wrapResponse);
    }