XPathJava通过测试值获取元素
我试图使用Xpath解析xml字符串,但我不知道如何使用表达式检索我想要的内容 我有以下xml内容:XPathJava通过测试值获取元素,java,xml,xpath,expression,Java,Xml,Xpath,Expression,我试图使用Xpath解析xml字符串,但我不知道如何使用表达式检索我想要的内容 我有以下xml内容: <root1> <root2> <A>something</A> <B>something</B> <C> <D> <E>DataE</E>
<root1>
<root2>
<A>something</A>
<B>something</B>
<C>
<D>
<E>DataE</E>
<F>DataF</F>
<G>something</G>
<H>something</H>
<I>
<J>
<K>DataK</K>
<L>DataL</L>
</J>
</I>
</D>
<D>
<E>DataE_ERROR</E>
<F>DataF</F>
<G>something</G>
<H>something</H>
<I>
<J>
<K>DataK</K>
<L>DataL</L>
</J>
</I>
</D>
</C>
</root2>
</root1>
某物
某物
达泰
达塔夫
某物
某物
达塔克
数据
数据错误
达塔夫
某物
某物
达塔克
数据
例如,当E的值是DataE时,我想得到F,K,L的值
我正在使用Xpath,但找不到好的表达式
以下是我的java代码:
public void getit()
{
String xml = "The xml above";
DocumentBuilderFactory f = DocumentBuilderFactory.newInstance();
DocumentBuilder b = f.newDocumentBuilder();
Document d = b.parse(new InputSource(new StringReader(xml)));
d.getDocumentElement().normalize();
// No idea ! how can i make it work by testing the value of E
String expression = "//E/text()|//F/text()|//K/text()|//L/text()";
XPath xPath = XPathFactory.newInstance().newXPath();
Object result = xPath.compile(expression).evaluate(d, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getNodeValue());
}
}
public void getit()
{
String xml=“上面的xml”;
DocumentBuilderFactory f=DocumentBuilderFactory.newInstance();
DocumentBuilder b=f.newDocumentBuilder();
文档d=b.parse(新的InputSource(新的StringReader(xml));
d、 getDocumentElement().normalize();
//不知道!我怎样才能通过测试E的值来让它工作呢
字符串表达式=“//E/text()|//F/text()|//K/text()|//L/text()”;
XPath=XPathFactory.newInstance().newXPath();
Object result=xPath.compile(expression).evaluate(d,XPathConstants.NODESET);
节点列表节点=(节点列表)结果;
对于(int i=0;i
为了确保查询正常工作,我修改了示例XML,如下所示
<root1>
<root2>
<A>something</A>
<B>something</B>
<C>
<D>
<E>DataE</E>
<F>DataF 1</F>
<G>something</G>
<H>something</H>
<I>
<J>
<K>DataK 1</K>
<L>DataL 1</L>
</J>
</I>
</D>
<D>
<E>DataE_ERROR</E>
<F>DataF 2</F>
<G>something</G>
<H>something</H>
<I>
<J>
<K>DataK 2</K>
<L>DataL 2</L>
</J>
</I>
</D>
</C>
</root2>
</root1>
基本上,这是
查找任何F
节点,其祖先包含D
,其子节点E
的文本等于DataE
或
现在,这一点很重要,您可以使用。/
查找父节点,但是K
和L
隐藏在子节点中,我不确定它们是更深还是浅,所以我选择了这种方法
您可能需要对其进行一些改进,但我认为D/E
的关系非常重要
通过这个(和下面的例子),我能够生成以下输出
Found DataF 1
Found DataK 1
Found DataL 1
可运行示例:
public class TestXPath {
public static void main(String[] args) {
String xml = "The xml above";
try {
DocumentBuilderFactory f = DocumentBuilderFactory.newInstance();
DocumentBuilder b = f.newDocumentBuilder();
Document d = b.parse(new File("Values.xml"));
d.getDocumentElement().normalize();
String expression = "//F[ancestor::D/E[text()='DataE']]|//K[ancestor::D/E[text()='DataE']]|//L[ancestor::D/E[text()='DataE']]";
XPath xPath = XPathFactory.newInstance().newXPath();
Object result = xPath.compile(expression).evaluate(d, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
System.out.println("Found " + node.getTextContent());
}
} catch (ParserConfigurationException | SAXException | IOException | XPathExpressionException | DOMException exp) {
exp.printStackTrace();
}
}
}
公共类TestXPath{
公共静态void main(字符串[]args){
String xml=“上面的xml”;
试一试{
DocumentBuilderFactory f=DocumentBuilderFactory.newInstance();
DocumentBuilder b=f.newDocumentBuilder();
文档d=b.parse(新文件(“Values.xml”);
d、 getDocumentElement().normalize();
字符串表达式=“//F[祖先::D/E[text()='DataE']]|//K[祖先::D/E[text()='DataE']]|//L[祖先::D/E[text()='DataE']]”;
XPath=XPathFactory.newInstance().newXPath();
Object result=xPath.compile(expression).evaluate(d,XPathConstants.NODESET);
节点列表节点=(节点列表)结果;
对于(int i=0;i
这只是一个小问题,谢谢,如果我想通过示例在J和K之间添加另一个关系(仅当K=dataK时才显示J),我该怎么做呢?首先让该查询起作用……我怀疑类似于//J[祖先::K[text()='dataK']]
的东西可能会起作用……对不起。。我指的是K和L之间的关系。(仅当K=dataK时才显示L)我尝试了以下方法://F[祖先::D/E[text()='DataE']]|//L[祖先::J/K[text()='dataK']]
。。但是缺少“E”验证我能做的最好的事情就是给你父节点,//D[E[text()='DataE']和后代::K[text()='DataK']]
,然后你可以使用这个和另一个xPath查询来找到子节点……或者你可以尝试//F[祖先::D/E[text()='DataE']和祖先::D/后代::K[text()='DataK'].//L[祖先::D/E[text()='DataE']和祖先::D/genderant::K[text()='DataK']]
-满嘴都是:P
public class TestXPath {
public static void main(String[] args) {
String xml = "The xml above";
try {
DocumentBuilderFactory f = DocumentBuilderFactory.newInstance();
DocumentBuilder b = f.newDocumentBuilder();
Document d = b.parse(new File("Values.xml"));
d.getDocumentElement().normalize();
String expression = "//F[ancestor::D/E[text()='DataE']]|//K[ancestor::D/E[text()='DataE']]|//L[ancestor::D/E[text()='DataE']]";
XPath xPath = XPathFactory.newInstance().newXPath();
Object result = xPath.compile(expression).evaluate(d, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
System.out.println("Found " + node.getTextContent());
}
} catch (ParserConfigurationException | SAXException | IOException | XPathExpressionException | DOMException exp) {
exp.printStackTrace();
}
}
}