Java中用于XPath求值的绑定命名空间

import javax.xml.namespace.NamespaceContext;
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 java.util.Iterator;

public class XPathExample {
    public static void main(String[] args) throws XPathExpressionException {
        // 创建XPath对象
        XPathFactory xpathFactory = XPathFactory.newInstance();
        XPath xpath = xpathFactory.newXPath();

        // 创建命名空间上下文
        NamespaceContext namespaceContext = new NamespaceContext() {
            @Override
            public String getNamespaceURI(String prefix) {
                if ("ns".equals(prefix)) {
                    return "http://www.example.com/namespace";
                }
                return null;
            }

            @Override
            public String getPrefix(String namespaceURI) {
                if ("http://www.example.com/namespace".equals(namespaceURI)) {
                    return "ns";
                }
                return null;
            }

            @Override
            public Iterator<String> getPrefixes(String namespaceURI) {
                return null;
            }
        };

        // 设置命名空间上下文
        xpath.setNamespaceContext(namespaceContext);

        // 编译XPath表达式
        XPathExpression expression = xpath.compile("/ns:root/ns:element");

        // 在XML文档中求值
        Object result = expression.evaluate(xmlDocument, XPathConstants.NODESET);

        // 处理结果
        // ...
    }
}