code: public SoapClient init(SoapProtocol protocol) {
  		// 创建消息工厂
  		try {
  			this.factory = MessageFactory.newInstance(protocol.getValue());
  			// 根据消息工厂创建SoapMessage
  			this.message = factory.createMessage();
  		} catch (SOAPException e) {
  			throw new SoapRuntimeException(e);
  		}
  
  		return this;
  	}
docs: 初始化
  
  @param protocol 协议版本枚举，见{@link SoapProtocol}
  @return this