code: public final static String getHeader(HttpServletRequest request, String name, String charset) {
  		final String header = request.getHeader(name);
  		if (null != header) {
  			try {
  				return new String(header.getBytes(CharsetUtil.ISO_8859_1), charset);
  			} catch (UnsupportedEncodingException e) {
  				throw new UtilException(StrUtil.format("Error charset {} for http request header.", charset));
  			}
  		}
  		return null;
  	}
docs: 获得请求header中的信息
  
  @param request 请求对象{@link HttpServletRequest}
  @param name 头信息的KEY
  @param charset 字符集
  @return header值