SAX 解析器可以在 Java 中使用 XPath 吗

使用SAX解析器在Java中使用XPath

java
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import javax.xml.xpath.*;
import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.io.*;
public class SAXXPathExample {
    public static void main(String[] args) {
        try {
            // 创建SAX解析器
            SAXParserFactory factory = SAXParserFactory.newInstance();
            SAXParser saxParser = factory.newSAXParser();
            // 创建XPath对象
            XPathFactory xPathfactory = XPathFactory.newInstance();
            XPath xpath = xPathfactory.newXPath();
            // 定义XPath表达式
            String expression = "/bookstore/book[price>10]/title";
            // 创建Handler来处理SAX事件
            DefaultHandler handler = new DefaultHandler() {
                boolean isTitle = false;
                public void startElement(String uri, String localName, String qName, Attributes attributes)
                        throws SAXException {
                    if (qName.equalsIgnoreCase("title")) {
                        isTitle = true;
                    }
                }
                public void endElement(String uri, String localName, String qName) throws SAXException {
                    if (qName.equalsIgnoreCase("title")) {
                        isTitle = false;
                    }
                }
                public void characters(char ch[], int start, int length) throws SAXException {
                    if (isTitle) {
                        System.out.println("Title: " + new String(ch, start, length));
                    }
                }
            };
            // 解析XML文件并执行XPath查询
            saxParser.parse(new File("books.xml"), handler);
            
            // 通过XPath执行查询
            DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
            Document doc = docBuilder.parse(new File("books.xml"));
            XPathExpression xpathExpr = xpath.compile(expression);
            NodeList nodeList = (NodeList) xpathExpr.evaluate(doc, XPathConstants.NODESET);
            // 输出查询结果
            for (int i = 0; i < nodeList.getLength(); i++) {
                Node node = nodeList.item(i);
                System.out.println("Title: " + node.getTextContent());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}