回答我自己的问题......我决定使用处理程序。所以我创建了一个类似于上面的 ExchangeAuthSupplier 的 SOAPHandler:
public class MyAuthenticationHandler implements SOAPHandler<SOAPMessageContext> {
    @Override
    public boolean handleMessage(SOAPMessageContext context) {
        final Boolean outInd = (Boolean) context.get(MessageContext.MESSAGE_OUTBOUND_PROPERTY);
        if (outInd.booleanValue()) {
            try {
                UserNamePasswordPair userNamePasswordPair = getAuthorization(); // Method to retrieve credentials from somewhere
                context.put(BindingProvider.USERNAME_PROPERTY, userNamePasswordPair.getUsername());
                context.put(BindingProvider.PASSWORD_PROPERTY, userNamePasswordPair.getPassword());
            } catch (final Exception e) {
                return false;
            }
        }
        return true;
    }
    @Override
    public boolean handleFault(SOAPMessageContext context) {
        logger.error("error occurred when getting auth.");
        return false;
    }
    @Override
    public void close(MessageContext context) {
        logger.debug("closing handler for auth...");
    }
    @Override
    public Set<QName> getHeaders() {
        return null;
    }
}
创建了一个 HandlerResolver 以将解析器添加到链中:
public class MyHandlerResolver implements HandlerResolver {
    private List<Handler> chain;
    public MyHandlerResolver() {
        chain = new ArrayList<Handler>();
        chain.add(new MyAuthenticationHandler();
    }
    @Override
    public List<Handler> getHandlerChain(PortInfo portInfo) {
        return chain;
    }
}
然后在 Spring 中,像这样把它全部连接起来:
<bean id="myJAXWSClient" class="org.springframework.remoting.jaxws.JaxWsPortProxyFactoryBean">
    <property name="serviceInterface" value="Interface to implement"/>
    <property name="wsdlDocumentUrl" value="classpath:/wsdl/theWsdl.wsdl"/>
    <property name="namespaceUri" value="namespace"/>
    <property name="serviceName" value="ServiceName"/>
    <property name="endpointAddress" value="/endpoint"/>
    <property name="handlerResolver" ref="myHandlerResolver"/>
</bean>
<bean id="myHandlerResolver" class="com.mystuff.ExchangeHandlerResolver"/>