Spring集成JAX-WS handler无法获取head中的内容 400 请求报错 

最近在做webservice程序时，由于要对数据做一个权限的校验，因此需要在请求信息中的head中添加username和password两个字段，webservice服务端需要对username和password进行校验，程序获取到的请求信息如下：

<?xml version='1.0' encoding='UTF-8'?><soapenv:Envelope xmlns:pp="http://pp.soa.csg.cn" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"> <soapenv:Header> <username xmlns:pp="http://pp.soa.csg.cn" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">test</username> <password xmlns:pp="http://pp.soa.csg.cn" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">test</password> </soapenv:Header> <soapenv:Body> <pp:test xmlns:pp="http://pp.soa.csg.cn" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xml="http://www.w3.org/XML/1998/namespace"> <arg0>test</arg0> </pp:test> </soapenv:Body> </soapenv:Envelope>

然而在handler中获取head中的username和password时，便获取不到了，handler代码如下：

public boolean handleMessage(SOAPMessageContext context) {
	boolean isExceSuc = true;
	Boolean isResponse = (Boolean) context.get(MessageContext.MESSAGE_OUTBOUND_PROPERTY);
		
	// 请求
	if(!isResponse){
		try {
				
			// 获取请求头信息
			SOAPMessage message = context.getMessage();
				
			SOAPEnvelope soapEnv = message.getSOAPPart().getEnvelope();  
		       SOAPHeader soapHeader = soapEnv.getHeader(); 
				
			if(soapHeader == null){
				generateSOAPErrMessage(message, "10004", "head is null");
			}
				
			String username = soapHeader.getAttribute("username");
			System.out.println("username:"+username);
			String password = soapHeader.getAttribute("password");
			System.out.println("password:"+password);
				
			if(!"test".equals(username) || !"test".equals(password)){
				generateSOAPErrMessage(message, "10005", "check security failed");
			}
		} catch (SOAPException e) {
				isExceSuc = false;
		}
	}
	return isExceSuc;
}

soapHeader的值为[soapenv:Header: null]

这里是applicationContext.xml配置文件的片段：

<wss:binding url="/ppservice">
   <wss:service >
      <ws:service bean="#ppWebService" >
         <ws:handlers >
           <ref bean="securityHandler"/>
         </ws:handlers>
      </ws:service>
   </wss:service>
</wss:binding>

web.xml

<servlet>
  	<servlet-name>JAXWSServlet</servlet-name>
  	<servlet-class>
   		com.sun.xml.ws.transport.http.servlet.WSSpringServlet
 	</servlet-class>
  	<load-on-startup>2</load-on-startup>
</servlet>
<servlet-mapping>
        <servlet-name>JAXWSServlet</servlet-name>
        <url-pattern>/ppservice</url-pattern>
</servlet-mapping>

各位大神请帮忙分析一下是什么原因导致的没有办法获取到head中的username与password值，万分感谢！！！