使用xpath获取xml指定节点或节点集工具类

ゝ一纸荒年。 2022-04-18 03:46 390阅读 0赞

**使用xpath获取xml指定节点的属性**

**1. XmlXPathUtil.java**

import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.StringReader;
 import java.io.UnsupportedEncodingException;
 import java.util.Iterator;
 import java.util.Map;
 
 import javax.xml.XMLConstants;
 import javax.xml.namespace.NamespaceContext;
 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.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.w3c.dom.Document;
 import org.w3c.dom.Node;
 import org.xml.sax.InputSource;
 import org.xml.sax.SAXException;
 import org.xml.sax.SAXParseException;
 
 /**
 * 
 * 
 * <DL>
 * <DT> 使用路径表达式(XPath)来获取XML文档中的节点或节点集工具类 </DT>
 * 
 * <DD>详细介绍</DD>
 * </DL>
 * 
 * 
 * <DL>
 * <DT>使用范例</DT>
 * 
 * <DD>使用范例说明</DD>
 * </DL>
 * 
 * 
 * @author 周典
 * @version
 */
 
 public class XmlXPathUtil {
 
 	private static final Log logger = LogFactory.getLog(XmlXPathUtil.class);
 
 	/** XML编码 */
 	private String encoding = "utf-8";
 
 	private NamespaceContext defaultNamespaceContext;
 
 	public XmlXPathUtil() {
 		defaultNamespaceContext = new NamespaceContext() {
 			private Map<String, String> m_prefixMap = null;
 
 			public String getNamespaceURI(String prefix) {
 				if (null == prefix) {
 					throw new NullPointerException("Null prefix");
 				} else {
 					if ("xml".equals(prefix)) {
 						return XMLConstants.XML_NS_URI;
 					}
 					if (null != m_prefixMap) {
 						for (String key : m_prefixMap.keySet()) {
 							if (key.equals(prefix)) {
 								return m_prefixMap.get(key);
 							}
 						}
 					}
 				}
 				return XMLConstants.NULL_NS_URI;
 			}
 
 			public String getPrefix(String uri) {
 				throw new UnsupportedOperationException();
 			}
 
 			public Iterator getPrefixes(String uri) {
 				throw new UnsupportedOperationException();
 			}
 		};
 	}
 
 	/**
 	 * 
 	 * 获取XPath的值
 	 * 
 	 * @param query
 	 * 
 	 * @param xmlDocument
 	 * 
 	 * @param defaultNamespaceContext
 	 * 
 	 * @return String
 	 */
 	public String evaluateXPath(String query, Node xmlDocument,
 			NamespaceContext defaultNamespaceContext) {
 		String result = null;
 		XPathFactory factory = XPathFactory.newInstance();
 		XPath xpath = factory.newXPath();
 		if (defaultNamespaceContext == null) {
 			defaultNamespaceContext = this.defaultNamespaceContext;
 		}
 		xpath.setNamespaceContext(defaultNamespaceContext);
 		XPathExpression expr = null;
 		try {
 			expr = xpath.compile(query);
 		} catch (XPathExpressionException xpee) {
 			Throwable x = xpee;
 			if (null != xpee.getCause()) {
 				x = xpee.getCause();
 				if ("javax.xml.transform.TransformerException".equals(x
 						.getClass().getName())) {
 					if (logger.isDebugEnabled()) {
 						logger.debug("xpath表达式错误：所有的命名空间需要转换。");
 					}
 				} else {
 					if (logger.isDebugEnabled()) {
 						logger.debug("xpath表达式错误：可能表达式格式有误。");
 					}
 				}
 			}
 			return null;
 		}
 		try {
 			result = (String) expr.evaluate(xmlDocument, XPathConstants.STRING);
 		} catch (XPathExpressionException e) {
 			e.printStackTrace();
 		}
 		return result;
 	}
 
 	/**
 	 * 加载XML String资源
 	 * 
 	 * @param xmlString
 	 * xml格式的字符串
 	 * @return Node
 	 * 
 	 */
 	public Node loadXMLResource(String xmlString) {
 		if (0xFEFF == xmlString.charAt(0)) {
 			xmlString = xmlString.substring(1);
 		}
 		InputSource source = new InputSource(new BufferedReader(
 				new StringReader(xmlString)));
 		return this.xmlSourceToDocument(source);
 	}
 
 	/**
 	 * 加载XML byte[]资源
 	 * 
 	 * @param xmlFile
 	 * xml文件
 	 * @return Node
 	 * 
 	 */
 	public Node loadXMLResource(byte xmlByte[]) {
 		String xmlString = "";
 		try {
 			xmlString = new String(xmlByte, encoding);
 		} catch (UnsupportedEncodingException e) {
 			if (logger.isDebugEnabled()) {
 				logger.debug(e.getMessage());
 			}
 		}
 		if (0xFEFF == xmlString.charAt(0)) {
 			xmlString = xmlString.substring(1);
 		}
 		InputSource source = new InputSource(new BufferedReader(
 				new StringReader(xmlString)));
 		return this.xmlSourceToDocument(source);
 	}
 
 	/**
 	 * 加载XML File资源
 	 * 
 	 * @param xmlFile
 	 * xml文件
 	 * @return Node
 	 * 
 	 */
 	public Node loadXMLResource(File xmlFile) {
 		InputSource source = null;
 		try {
 			source = new InputSource(new FileInputStream(xmlFile));
 		} catch (FileNotFoundException e) {
 			if (logger.isDebugEnabled()) {
 				logger.debug(e.getMessage());
 			}
 		}
 		return this.xmlSourceToDocument(source);
 	}
 
 	/**
 	 * 
 	 * 把xml source 转换为Document
 	 * 
 	 * @param source
 	 * 
 	 * @return
 	 * 
 	 */
 	private Node xmlSourceToDocument(InputSource source) {
 		source.setEncoding(encoding);
 		Document document = null;
 		try {
 			document = loadDocument(source);
 		} catch (SAXParseException spe) {
 			if (null != spe.getSystemId()) {
 				if (logger.isDebugEnabled()) {
 					logger.debug("xpath解析错误，出错的行数是：" + spe.getLineNumber()
 							+ "，uri：" + spe.getSystemId());
 					logger.debug(spe.getMessage());
 				}
 			} else {
 				if (logger.isDebugEnabled()) {
 					logger.debug(spe.getMessage());
 				}
 			}
 			Exception x = spe;
 			if (null != spe.getException()) {
 				x = spe.getException();
 			}
 		} catch (SAXException se) {
 			document = null;
 			if (logger.isDebugEnabled()) {
 				logger.debug("解析XML错误，请确保存在格式正确的XML文档。");
 			}
 			Exception x = se;
 			if (null != se.getException()) {
 				x = se.getException();
 			}
 		} catch (IOException ioe) {
 			document = null;
 			if (logger.isDebugEnabled()) {
 				logger.debug("不能加载文档，文档不可读取。");
 			}
 		}
 		return document;
 	}
 
 	/**
 	 * 
 	 * 从InputSource加载document
 	 * 
 	 * @param source
 	 * @return Node
 	 * @throws SAXException
 	 * @throws IOException
 	 */
 	private Document loadDocument(InputSource source) throws SAXException,
 			IOException {
 		Document document = null;
 		DocumentBuilder parser = null;
 		DocumentBuilderFactory domFactory = DocumentBuilderFactory
 				.newInstance();
 		domFactory.setNamespaceAware(true);
 		domFactory.setValidating(false);
 		try {
 			parser = domFactory.newDocumentBuilder();
 		} catch (ParserConfigurationException pce) {
 			if (logger.isDebugEnabled()) {
 				logger.debug(pce.getMessage());
 			}
 		}
 		parser.reset();
 		document = parser.parse(source);
 		return document;
 	}
 
 	/**
 	 * 
 	 * 设置xml编码
 	 * 
 	 * @param encoding
 	 */
 	public void setEncoding(String encoding) {
 		this.encoding = encoding;
 	}
 
 	/**
 	 * 
 	 * @param args
 	 */
 	public static void main(String[] args) {
 		String xmlString = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";
 		xmlString += "<books>";
 		xmlString += "<book><name>Action1</name></book>";
 		xmlString += "<book><name first='asdf'>Action2</name></book>";
 		xmlString += "</books>";
 		XmlXPathUtil xmlXPathUtil = new XmlXPathUtil();
 		xmlXPathUtil.setEncoding("utf-8");
 		Node fileNode = xmlXPathUtil
 				.loadXMLResource(new File(
 						"F:\\客户信息查询.xml"));
 		Node strNode = xmlXPathUtil.loadXMLResource(xmlString);
 		String strValue = xmlXPathUtil.evaluateXPath("//book", strNode, null);
 		String fileValue = xmlXPathUtil
 				.evaluateXPath(
 						"/service[ @name='' ]/sys-header/data[ @name='SYS_HEAD' ]/struct/data[ @name='MESSAGE_TYPE' ]/field[1]/text()",
 						fileNode, null);
 		System.out.println("execute result: " + strValue);
 		System.out.println("execute result: " + fileValue);
 	}
 }

**2. 客户信息查询.xml**

<?xml version="1.0" encoding="GB2312"?>
 <service name="">
 	<sys-header>
 		<data name="SYS_HEAD">
 			<struct>
 				<data name="MESSAGE_TYPE">
 					<field type="string" length="4" encrypt-mode="">1400</field>
 					<field type="string" length="4" encrypt-mode="">1401</field>
 				</data>
 				<data name="MESSAGE_CODE">
 					<field type="string" length="6" encrypt-mode="">9100</field>
 				</data>
 				<data name="SERVICE_CODE">
 					<field type="string" length="8" encrypt-mode="">SVR_INQUIRY1</field>
 					<field type="string" length="8" encrypt-mode="">SVR_INQUIRY2</field>
 				</data>
 			</struct>
 		</data>
 	</sys-header>
 	<app-header>
 		<data name="APP_HEAD">
 			<struct>
 				<data name="PGUP_OR_PGDN">
 					<field type="string" length="1" encrypt-mode="">1</field>
 				</data>
 				<data name="TOTAL_NUM">
 					<field type="string" length="10" encrypt-mode="">10</field>
 				</data>
 				<data name="CURRENT_NUM">
 					<field type="string" length="10" encrypt-mode="">0</field>
 				</data>
 				<data name="PAGE_START">
 					<field type="string" length="10" encrypt-mode="">0</field>
 				</data>
 				<data name="PAGE_END">
 					<field type="string" length="10" encrypt-mode="">0</field>
 				</data>
 			</struct>
 		</data>
 	</app-header>
 	<body>
 		<data name="CLIENT_NO">
 			<field type="string" length="12" encrypt-mode="">1234567890123</field>
 		</data>
 		<data name="GLOBAL_ID">
 			<field type="string" length="25" encrypt-mode="">1234567890123456789012345</field>
 		</data>
 		<data name="GLOBAL_TYPE">
 			<field type="string" length="3" encrypt-mode="">123</field>
 		</data>
 		<data name="ISS_COUNTRY">
 			<field type="string" length="3" encrypt-mode="">123</field>
 		</data>
 	</body>
 </service>