我正在尝试在Groovy中创建一个执行以下操作的函数：
- 在运行时接受2个参数（一串XML和一个xpath查询）
- 以文本形式返回结果
这可能非常简单，但有两个障碍：
- 这必须在groovy中完成
- 我对Groovy或Java几乎一无所知......
这是我通过黑客攻击各种代码而得到的，但现在我被卡住了：
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.*;
builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
doc = builder.parse(new ByteArrayInputStream(xml.bytes));
expr = XPathFactory.newInstance().newXPath().compile(expression);
Object result = expr.evaluate(doc, XPathConstants.NODESET)
其中“xml”和“expression”是运行时参数。我现在如何得到这个结果（作为字符串）？
谢谢
你可以这样做：
import javax.xml.xpath.*
import javax.xml.parsers.DocumentBuilderFactory
def testxml = '''
<records>
<car name="HSV Maloo" make="Holden" year="2006">
<country>Australia</country>
<record type="speed">Production Pickup Truck with speed of 271kph</record>
</car>
</records>
'''
def processXml( String xml, String xpathQuery ) {
def xpath = XPathFactory.newInstance().newXPath()
def builder = DocumentBuilderFactory.newInstance().newDocumentBuilder()
def inputStream = new ByteArrayInputStream( xml.bytes )
def records = builder.parse(inputStream).documentElement
xpath.evaluate( xpathQuery, records )
}
println processXml( testxml, '//car/record/@type' )
看看这个页面（以前是Groovy Docs的一部分），了解如何循环返回多个结果的XPath查询：
http://groovy.jmiguel.eu/groovy.codehaus.org/Reading+XML+with+Groovy+and+XPath.html
你可以这样做：
import javax.xml.xpath.*
import javax.xml.parsers.DocumentBuilderFactory
def testxml = '''
<records>
<car name="HSV Maloo" make="Holden" year="2006">
<country>Australia</country>
<record type="speed">Production Pickup Truck with speed of 271kph</record>
</car>
</records>
'''
def processXml( String xml, String xpathQuery ) {
def xpath = XPathFactory.newInstance().newXPath()
def builder = DocumentBuilderFactory.newInstance().newDocumentBuilder()
def inputStream = new ByteArrayInputStream( xml.bytes )
def records = builder.parse(inputStream).documentElement
xpath.evaluate( xpathQuery, records )
}
println processXml( testxml, '//car/record/@type' )
看看这个页面（以前是Groovy Docs的一部分），了解如何循环返回多个结果的XPath查询：
http://groovy.jmiguel.eu/groovy.codehaus.org/Reading+XML+with+Groovy+and+XPath.html
这是我最终解决的问题，这应该适用于我的目的：
import javax.xml.xpath.*
import javax.xml.parsers.DocumentBuilderFactory
def processXml( String xml, String xpathQuery ) {
def xpath = XPathFactory.newInstance().newXPath()
def builder = DocumentBuilderFactory.newInstance().newDocumentBuilder()
def inputStream = new ByteArrayInputStream( xml.bytes )
def records = builder.parse(inputStream).documentElement
def nodes = xpath.evaluate( xpathQuery, records, XPathConstants.NODESET )
nodes.collect { node -> node.textContent }
}
processXml( xml, query )