如何使用XPATH到达特定的子节点？

Question

我有一个XML文件，我正试图解析它以获得名为Result的标记。

使用xpathname（//results/*）和count（//results/*），我可以看到results有10个子节点，每个节点都被命名为Result。但如果我使用以下任何一种XPath，就没有匹配项：

• //结果
• /查询/结果/结果[1]
• /查询/结果/结果

我所做的一切都不是返回任何Result标记。但是我知道有10个。我可以通过/查询/结果获得结果，所以我知道我正在连接到这个文件。我如何生成一个xpath来到达每个Result？

XML结构（缩写）：

<?xml version="1.0" encoding="UTF-8"?>
<query xmlns:yahoo="http://www.yahooapis.com/v1/base.rng"
    yahoo:count="10" yahoo:created="2013-07-17T15:15:52Z" yahoo:lang="en-US">
    <diagnostics>
    </diagnostics> 
    <results>
        <Result id="11762112" xmlns="urn:yahoo:lcl">
            <Title>California Rollin' Sushi Bar</Title>
            <Address>274 Goodman St N</Address>
            <City>Rochester</City>
            <State>NY</State>
            <Phone>[phone]</Phone>
            <Latitude>43.158685</Latitude>
            <Longitude>-77.585197</Longitude>
            <Rating>
                <AverageRating>3</AverageRating>
                <TotalRatings>10</TotalRatings>
                <TotalReviews>10</TotalReviews>
                <LastReviewDate>1341259499</LastReviewDate>
                <LastReviewIntro> I went with my two girls last week and was told it would be around 1-1/2 wait so we had our name put on list hoping we would get seated sooner. It was busy because the groupons were expiring (which they knew ahead of time, so one would think they would be prepared). Well needless to say after 1-1/2 we still were not seated and there were several tables available. I asked how much longer and the hostess said another hour. I told her we have already been waiting for 1 hour she smirked and said sorry. People were coming in after us and being seated which made one of my girls ask the question why do they get a table before us. I went back in and said since my kids are tired is there anyway I could order take out and use my groupon since I am here and of course the hostess replied no its for dine in only. Ugh we left and ate elsewhere. I did call to speak with the manager who really was more concerned about telling me how proud she was of her staff and really didnt seem to care about our awful experience. Too bad because they lost several customers that night. What ever happend to customer service?</LastReviewIntro>
            </Rating>
            <Distance>1.57</Distance>
            <Url>http://local.yahoo.com/info-11762112-california-rollin-sushi-bar-rochester</Url>
            <ClickUrl>http://local.yahoo.com/info-11762112-california-rollin-sushi-bar-rochester</ClickUrl>
            <MapUrl>http://local.yahoo.com/info-11762112-california-rollin-sushi-bar-rochester?viewtype=map</MapUrl>
            <BusinessUrl>http://californiarollin.com/</BusinessUrl>
            <BusinessClickUrl>http://californiarollin.com/</BusinessClickUrl>
            <Categories>
                <Category id="96926236">Restaurants</Category>
                <Category id="96926205">Sushi Restaurants</Category>
            </Categories>
        </Result>
    </results>
</query>

Answer 1

我尝试了你的xml，不得不关闭results标记，我认为这是你复制和粘贴xml的一部分。除此之外，一切正常。我添加了更多的Result标签来测试它，得到了预期的结果。过来看：

import java.io.FileInputStream;
import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class TestXpath {
    public static void main(String[] args) throws IOException, SAXException, IOException, ParserConfigurationException, XPathExpressionException {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document parse = builder.parse(new FileInputStream("test.xml"));

        XPathFactory xPathfactory = XPathFactory.newInstance();
        XPath xpath = xPathfactory.newXPath();
        XPathExpression expr = xpath.compile("/query/results/Result[2]");

        NodeList nl = (NodeList)  expr.evaluate(parse, XPathConstants.NODESET);
        for (int i = 0; i < nl.getLength(); i++) {
            Node item = nl.item(i);
            System.out.println(item.getNodeName());
            System.out.println(item.getTextContent());
        }
    }
}

输出：

Result

            California  2 Rollin' Sushi Bar
            274 Goodman St N
            Rochester
            NY
            [phone]
            43.158685
            -77.585197

                3
                10
                10
                1341259499
                 I went with my two girls last week and was told it would be around 1-1/2 wait so we had our name put on list hoping we would get seated sooner. It was busy because the groupons were expiring (which they knew ahead of time, so one would think they would be prepared). Well needless to say after 1-1/2 we still were not seated and there were several tables available. I asked how much longer and the hostess said another hour. I told her we have already been waiting for 1 hour she smirked and said sorry. People were coming in after us and being seated which made one of my girls ask the question why do they get a table before us. I went back in and said since my kids are tired is there anyway I could order take out and use my groupon since I am here and of course the hostess replied no its for dine in only. Ugh we left and ate elsewhere. I did call to speak with the manager who really was more concerned about telling me how proud she was of her staff and really didnt seem to care about our awful experience. Too bad because they lost several customers that night. What ever happend to customer service?

            1.57
            http://local.yahoo.com/info-11762112-california-rollin-sushi-bar-rochester
            http://local.yahoo.com/info-11762112-california-rollin-sushi-bar-rochester
            http://local.yahoo.com/info-11762112-california-rollin-sushi-bar-rochester?viewtype=map
            http://californiarollin.com/
            http://californiarollin.com/

                Restaurants
                Sushi Restaurants

请注意California 2指示它是第二个Result条目。

我还尝试了//Result和/query/results/Result。

您手头的xml有什么问题吗？你能用我发的代码试试吗？干杯

Answer 2

元素结果属于默认名称空间“urn:yahoo:lcl”。见问题的答案：

使用XPath获取具有默认命名空间（无命名空间前缀）的元素