<Type>  
    <Source>        
        <TimeStamp>2016-02-19T12:27:06.387Z</TimeStamp>
        <IPAddress IPVersion="IPv4">x.xx.xxx.xxx</IPAddress>
        <Port>64435</Port>
        <DNS_Name>x.xx.xxx.xxx.range9-27.abc.com</DNS_Name>
    </Source>
 </Type>

我正在尝试使用下面的代码从上面的标签中检索所有值.

REGISTER piggybank-0.15.0.jar
            DEFINE XPath org.apache.pig.piggybank.evaluation.xml.XPath();

        A =  LOAD 'test.xml' using org.apache.pig.piggybank.storage.XMLLoader('Type') as (x:chararray);
        B = FOREACH A GENERATE 
                               XPath(x,'Source/TimeStamp'),XPath(x,'Source/IPAddress'),'Source/IPAddress/@IPVersion'),'Source/Port'),'Source/DNS_Name');

当我转储B时,我得到以下输出,其中缺少IPVersion的值.

(2016-02-19T12:27:06.387Z,x.xx.xxx.xxx,64435,x.xx.xxx.xxx.range9-27.abc.com)

有谁可以帮我解决这个问题？