logstash-input-file 读取xml 为啥通过"/xmldata/head2/key3/text()", "key3" 类似的解析，字段keys3是数组啊

filter 关于xml的配置
xml{
store_xml =>false
source => "message"
xpath => [
"/xmldata/head1/id/text()", "id",
"/xmldata/head1/date/text()", "date",
"/xmldata/head1/key1/text()", "key1",
"/xmldata/head2/key3/text()", "key3"
]
}

xml文件：
<xmldata>
<head1>
<key1>Value1</key1>
<key2>Value2</key2>
<id>0001</id>
<date>Aug 13 2011 00:03:44</date>
</head1>
<head2>
<key3>Value3</key3>
</head2>
</xmldata>



结果拿到的结果每个字段却是数组，我想要是的string

该如何配置？