<table index="1" title=" Final year marks of BIT students" ref="BIT results">
<headings>
<heading>Semester1</heading>
<heading>Semester2</heading>
<heading>Semester3</heading>
<heading>Semester4</heading>
<heading>Grade</heading>
<heading>FYP</heading>
</headings>
<tablebody>
<tablerow>
<tablecell><item>10</item></tablecell>
<tablecell><item>12</item></tablecell>
<tablecell><item>13</item></tablecell>
<tablecell><item>15</item></tablecell>
<tablecell><item>B</item></tablecell>
<tablecell><item>B</item></tablecell>
</tablerow>
</tablebody>
</table>
<table index="2" title="Final year marks of COM students" ref="COM results">
<headings>
<heading>Semester1</heading>
<heading>Semester2</heading>
<heading>Semester3</heading>
<heading>Semester4</heading>
<heading>Grade</heading>
<heading>FYP</heading>
</headings>
<tablebody>
<tablerow>
<tablecell><item>15</item></tablecell>
<tablecell><item>15</item></tablecell>
<tablecell><item>15</item></tablecell>
<tablecell><item>14</item></tablecell>
<tablecell><item>A</item></tablecell>
<tablecell><item>A</item></tablecell>
</tablerow>
<tablerow>
<tablecell><item>10</item></tablecell>
<tablecell><item>5</item></tablecell>
<tablecell><item>9</item></tablecell>
<tablecell><item>11</item></tablecell>
<tablecell><item>C</item></tablecell>
<tablecell><item>C</item></tablecell>
</tablerow>
</tablebody>
</table>``
嗨，我是Xpath的新手。我需要使用Xpath提取XML表数据。这是我的XML代码。我试过，但无法获得成功的输出。
The output table would be like this
semester1 semester2 semester3 semester4 grade fyp
10 11 13 12 A B
有没有人知道最好的方法来解决这个问题？谢谢:)
答案 0 :(得分：1)
首先，您的示例XML无效。您已经提供了两个单独的示例，或者您错过了周围的父标记。
我假设了第二个，并在<tables></tables>标签中包含了您的示例。
所以现在基于此...
<tables>
<table index="1" title=" Final year marks of BIT students" ref="BIT results">
<headings>
<heading>Semester1</heading>
<heading>Semester2</heading>
<heading>Semester3</heading>
<heading>Semester4</heading>
<heading>Grade</heading>
<heading>FYP</heading>
</headings>
<tablebody>
<tablerow>
<tablecell>
<item>10</item>
</tablecell>
<tablecell>
<item>12</item>
</tablecell>
<tablecell>
<item>13</item>
</tablecell>
<tablecell>
<item>15</item>
</tablecell>
<tablecell>
<item>B</item>
</tablecell>
<tablecell>
<item>B</item>
</tablecell>
</tablerow>
</tablebody>
</table>
<table index="2" title="Final year marks of COM students" ref="COM results">
<headings>
<heading>Semester1</heading>
<heading>Semester2</heading>
<heading>Semester3</heading>
<heading>Semester4</heading>
<heading>Grade</heading>
<heading>FYP</heading>
</headings>
<tablebody>
<tablerow>
<tablecell>
<item>15</item>
</tablecell>
<tablecell>
<item>15</item>
</tablecell>
<tablecell>
<item>15</item>
</tablecell>
<tablecell>
<item>14</item>
</tablecell>
<tablecell>
<item>A</item>
</tablecell>
<tablecell>
<item>A</item>
</tablecell>
</tablerow>
<tablerow>
<tablecell>
<item>10</item>
</tablecell>
<tablecell>
<item>5</item>
</tablecell>
<tablecell>
<item>9</item>
</tablecell>
<tablecell>
<item>11</item>
</tablecell>
<tablecell>
<item>C</item>
</tablecell>
<tablecell>
<item>C</item>
</tablecell>
</tablerow>
</tablebody>
</table>
</tables>
我能够使用......
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
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) {
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(new File("Table.xml"));
XPathFactory xFactory = XPathFactory.newInstance();
XPath path = xFactory.newXPath();
XPathExpression exp = path.compile("/tables/table");
NodeList nlTables = (NodeList) exp.evaluate(doc, XPathConstants.NODESET);
for (int tblIndex = 0; tblIndex < nlTables.getLength(); tblIndex++) {
Node table = nlTables.item(tblIndex);
Node nAtt = table.getAttributes().getNamedItem("title");
System.out.println("Showing results for " + (nAtt == null ? "[Unknown]" : nAtt.getTextContent()));
exp = path.compile("headings/heading");
NodeList nlHeaders = (NodeList) exp.evaluate(table, XPathConstants.NODESET);
Set<String> headers = new HashSet<String>(25);
for (int index = 0; index < nlHeaders.getLength(); index++) {
headers.add(nlHeaders.item(index).getTextContent().trim());
}
for (String header : headers) {
System.out.printf("%-20s", header);
}
System.out.println("");
exp = path.compile("tablebody/tablerow");
NodeList nlRows = (NodeList) exp.evaluate(table, XPathConstants.NODESET);
for (int index = 0; index < nlRows.getLength(); index++) {
Node rowNode = nlRows.item(index);
exp = path.compile("tablecell/item");
NodeList nlValues = (NodeList) exp.evaluate(rowNode, XPathConstants.NODESET);
List<String> values = new ArrayList<String>(25);
for (int valueIndex = 0; valueIndex < nlValues.getLength(); valueIndex++) {
values.add(nlValues.item(valueIndex).getTextContent().trim());
}
for (String value : values) {
System.out.printf("%-20s", value);
}
System.out.println("");
}
System.out.println("");
}
} catch (ParserConfigurationException exp) {
exp.printStackTrace();
} catch (SAXException | IOException | XPathExpressionException ex) {
ex.printStackTrace();
}
}
}
生产......
Showing results for Final year marks of BIT students
Semester1 Semester2 Semester3 Semester4 FYP Grade
10 12 13 15 B B
Showing results for Final year marks of COM students
Semester1 Semester2 Semester3 Semester4 FYP Grade
15 15 15 14 A A
10 5 9 11 C C
基本上，您需要能够将每个部分分解为可管理的部分......
看看XPath Tutorial并阅读有关XPath的所有关于XP的帖子;）