对XML进行增删改查

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<services>
    <service id="1001" name="a服务">
        <url>http://192.168.1.1:8080/PublicInfo/</url>
        <state/>       
    </service>
   
    <service id="1002" name="b服务">
        <url>http://192.168.1.2:8080/ETCMessageService</url>
        <state/>       
    </service>
</services>

 上面是本次要解析的XML文件。

package cn.microvideo.info.util;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import cn.microvideo.info.domain.ServiceMonitorInfo;
/**
 * 
 * @author zhouhy
 *
 */
public class XMLUtil {
	private XPath xpath = XPathFactory.newInstance().newXPath();
	private Logger log = Logger.getLogger(XMLUtil.class);
	/**
	 * 获取所有监控服务
	 * @param document
	 * @param value
	 * @return
	 */
	public List<ServiceMonitorInfo> getServices(Document document) {
		List<ServiceMonitorInfo> services = new ArrayList<ServiceMonitorInfo>();
		NodeList nodelist = document.getElementsByTagName("service");
		for (int i = 0; i < nodelist.getLength(); i++) {
			ServiceMonitorInfo service = new ServiceMonitorInfo();
			Element serviceNode = (Element) nodelist.item(i);
			String serviceName = serviceNode.getAttribute("name");
			String id = serviceNode.getAttribute("id");
			String url = null;
			String state = null;
			NodeList listnode = serviceNode.getChildNodes();
			for (int j = 0; j < listnode.getLength(); j++) {
				Node nd = listnode.item(j);
				if("url".equals(nd.getNodeName())){
					url = nd.getTextContent();
				}else if("state".equals(nd.getNodeName())){
					state = nd.getTextContent();
				}
			}
			service.setServiceName(serviceName);
			service.setUrl(url);
			service.setState(state);
			service.setId(id);
			services.add(service);
		}
		return services;
	}

	/**
	 * 根据ID查询服务
	 * @param document
	 * @param value
	 * @return
	 */
	public ServiceMonitorInfo findNodeByAttrValue(Document document, String code) {
		if(StringUtils.isBlank(code)){
			return null;
		}
		ServiceMonitorInfo service = new ServiceMonitorInfo();
		NodeList nodelist = document.getElementsByTagName("service");
		// 遍历
		for (int i = 0; i < nodelist.getLength(); i++) {
			Element serviceNode = (Element) nodelist.item(i);
			String val = serviceNode.getAttribute("id");
			if(code.equals(val)){
				String serviceName = serviceNode.getAttribute("name");
				String id = serviceNode.getAttribute("id");
				String url = null;
				String state = null;
				NodeList listnode = serviceNode.getChildNodes();
				for (int j = 0; j < listnode.getLength(); j++) {
					Node nd = listnode.item(j);
					if("url".equals(nd.getNodeName())){
						url = nd.getTextContent();
					}else if("state".equals(nd.getNodeName())){
						state = nd.getTextContent();
					}
				}
				service.setServiceName(serviceName);
				service.setUrl(url);
				service.setState(state);
				service.setId(id);
			}
		}
		return service;
	}

	/**
	 * 删除某个节点对象
	 * @param document
	 * @param id
	 * @throws TransformerException
	 * @throws XPathExpressionException 
	 * @throws UnsupportedEncodingException 
	 */
	public void deleteNodeById(Document document, ServiceMonitorInfo serviceInfo) throws TransformerException, XPathExpressionException, UnsupportedEncodingException {
		NodeList services = (NodeList) xpath.evaluate("//service[@id='"+serviceInfo.getId()+"']", document, XPathConstants.NODESET);
		Node node =  services.item(0);
		if(node != null){
			node.getParentNode().removeChild(node);
			TransformerFactory transformerFactory = TransformerFactory.newInstance();
			Transformer transformer = transformerFactory.newTransformer();
			URL url = Thread.currentThread().getContextClassLoader().getResource("cn/microvideo/info/config/servicemonitor.xml");
			String path =URLDecoder.decode(url.getPath(),"UTF-8");
			log.info("删除服务监控："+serviceInfo.toString());
			transformer.transform(new DOMSource(document), new StreamResult( new File(path)));
		}
	}

	/**
	 * 更新某个节点
	 * @param document
	 * @param id
	 * @throws TransformerException
	 * @throws XPathExpressionException 
	 * @throws UnsupportedEncodingException 
	 */
	public void updateNodeById(Document document, ServiceMonitorInfo serviceInfo) throws TransformerException, XPathExpressionException, UnsupportedEncodingException {
		NodeList services = (NodeList) xpath.evaluate("//service[@id='"+serviceInfo.getId()+"']", document, XPathConstants.NODESET);
		Element node = (Element) services.item(0);
		if(node == null){
			addNode(document, serviceInfo);
		}
		NodeList nodelist = node.getChildNodes();
		for (int i = 0; i < nodelist.getLength(); i++) {
			Node n = nodelist.item(i);
			if (n.getNodeType() == Node.ELEMENT_NODE) {
				if (n.getNodeName().equals("url")) {
					n.setTextContent(serviceInfo.getUrl());
				} else if (n.getNodeName().equals("state")) {
					n.setTextContent(serviceInfo.getState());
				}
			}
		}

		TransformerFactory transformerFactory = TransformerFactory.newInstance();
		Transformer transformer = transformerFactory.newTransformer();
		URL url = Thread.currentThread().getContextClassLoader().getResource("cn/microvideo/info/config/servicemonitor.xml");
		String path =URLDecoder.decode(url.getPath(),"UTF-8");
		log.info("修改服务监控："+serviceInfo.toString());
		transformer.transform(new DOMSource(document), new StreamResult( new File(path)));
	}

	/**
	 * 在指定的节点下方添加新得某个节点
	 * @param document
	 * @param id
	 * @throws TransformerException
	 * @throws XPathExpressionException 
	 * @throws UnsupportedEncodingException 
	 */
	public void addNode(Document document, ServiceMonitorInfo serviceInfo) throws TransformerException, XPathExpressionException, UnsupportedEncodingException {
		NodeList nodelist = (NodeList) xpath.evaluate("//service[@id='"+serviceInfo.getId()+"']", document, XPathConstants.NODESET);
		Element node = (Element) nodelist.item(0);
		if(node != null){
			updateNodeById(document, serviceInfo);
			return;
		}
		Element parentNode = document.getDocumentElement();
		Element nd = document.createElement("service");
		nd.setAttribute("name", serviceInfo.getServiceName());
		nd.setAttribute("id", serviceInfo.getId());
		Node url = document.createElement("url");
		url.appendChild(document.createTextNode(serviceInfo.getUrl()));
		Node state = document.createElement("state");
		state.appendChild(document.createTextNode(serviceInfo.getState()));
		nd.appendChild(url);
		nd.appendChild(state);
		parentNode.appendChild(nd);

		TransformerFactory transformerFactory = TransformerFactory.newInstance();
		Transformer transformer = transformerFactory.newTransformer();
		URL resource = Thread.currentThread().getContextClassLoader().getResource("cn/microvideo/info/config/servicemonitor.xml");
		String path =URLDecoder.decode(resource.getPath(),"UTF-8");
		log.info("增加服务监控："+serviceInfo.toString());
		transformer.transform(new DOMSource(document), new StreamResult( new File(path)));
	}

	public Document getDocument() throws ParserConfigurationException, SAXException, IOException, TransformerException, XPathExpressionException {
		DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
		DocumentBuilder builder = builderFactory.newDocumentBuilder();
		InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("cn/microvideo/info/config/servicemonitor.xml");
		Document document = builder.parse(is);
		return document;
	}

	public static void main(String[] args) {
		XMLUtil xml = new XMLUtil();
		try {
			ServiceMonitorInfo serviceInfo = new ServiceMonitorInfo();
			serviceInfo.setId("1003");
			serviceInfo.setServiceName("中心数据库");
			serviceInfo.setState("正常");
			serviceInfo.setUrl("http://demo.cn");
			xml.addNode(xml.getDocument(), serviceInfo);
		} catch (ParserConfigurationException | SAXException | IOException e) {
			e.printStackTrace();
		} catch (TransformerException e) {
			e.printStackTrace();
		} catch (XPathExpressionException e) {
			e.printStackTrace();
		}
	}
}