axis2怎么设置http请求头

我需要在发送的http的请求头,加"Accept-Language":"ZH",
stub._getServiceClient().getOptions().setProperty("Accept-Language","ZH",;没有效果
请问怎么添加http请求头

如下：

 List<Header> headers = (List<Header>) serviceClient.getOptions().getProperty(HTTPConstants.HTTP_HEADERS);  
if (headers == null){  
    headers = new ArrayList<Header>();
}
headers.add(new Header("Accept-Language", "ZH"));  
serviceClient.getOptions().setProperty(HTTPConstants.HTTP_HEADERS, headers);