public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { 
  HttpServletRequest req = (HttpServletRequest) request; 
  if("GET".equals(req.getMethod())){ 
   EncodingRequestWrapper wrapper = new EncodingRequestWrapper(req); 
   chain.doFilter(wrapper, response); 
  }else{ 
   req.setCharacterEncoding("UTF-8"); 
   chain.doFilter(request, response); 
  } 
}

public class EncodingRequestWrapper extends HttpServletRequestWrapper { 
 private HttpServletRequest request; 
 public EncodingRequestWrapper(HttpServletRequest request) { 
  super(request); 
  this.request = request; 
 } 
 @Override 
 public String getParameter(String name) { 
  String value = request.getParameter(name); 
  if(value!=null){ 
   try { 
    value = new String(value.getBytes("ISO8859-1"), "UTF-8"); 
   } catch (UnsupportedEncodingException e) { 
    e.printStackTrace(); 
   } 
  } 
  return value; 
 } 
}