xml文件讀取工具類

package cn.w.agent.common.util;

import java.io.File;
import java.net.URL;
import java.util.Iterator;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
/**
 * 參考http://blog.csdn.net/seayqrain/article/details/5024068
 * @author zheng_anbang
 *
 */
public class XmlReaderUtil {
	
	private XmlReaderUtil() {

	}

	private static XmlReaderUtil instance;

	public static XmlReaderUtil getInstance() {
		if (instance == null) {
			instance = new XmlReaderUtil();
		}
		return instance;
	}
	/**
	 * 讀取絕對路徑下的文件
	 * @param absPath
	 * @return
	 * @throws DocumentException
	 */
	public Document readSystemPathFile(String absPath) throws DocumentException {
		File file = new File(absPath);
		SAXReader reader = new SAXReader();
		Document d = reader.read(file);
		return d;
	}
	/**
	 * 讀取類路徑或者resource中的文件
	 * @param fileName
	 * @return
	 * @throws DocumentException
	 */
	public Document readClassPathFile(String fileName) throws DocumentException {
		URL file = ClassLoader.getSystemResource(fileName);
		SAXReader reader = new SAXReader();
		Document d = reader.read(file);
		return d;
		/*
		 * Element root = d.getRootElement();
		 * System.out.println(root.getName()); Element foo; for (Iterator i =
		 * root.elementIterator("Component"); i.hasNext();) { foo = (Element)
		 * i.next(); if(foo.elementText("jarName").equals(f.getName())){ } }
		 */
	}
	
	public Element getEle(Document d, String xpath){
		List rowList = d.selectNodes(xpath);
		for (Iterator iter = rowList.iterator(); iter.hasNext();) {
			return (Element) iter.next();
		}
		return null;
	}
	
	/*
	 public void readEle(Document d, String xpath) {
		// 獲取指定路徑下的元素列表,這裏指獲取所有的data下的row元素
		List rowList = d.selectNodes(xpath);
		// 獲得具體的row元素
		for (Iterator iter = rowList.iterator(); iter.hasNext();) {
			Element element = (Element) iter.next();
			// 獲得row元素的所有屬性列表
			List elementList = element.attributes();
			for (Iterator iter1 = elementList.iterator(); iter1.hasNext();) {
				// 將每個屬性轉化爲一個抽象屬性，然後獲取其名字和值
				AbstractAttribute aa = (AbstractAttribute) iter1.next();
				System.out.println("Name:" + aa.getName() + ";Value:"
						+ aa.getValue());
			}

			System.out.println(element.getName());
			System.out.println(element.attributeValue("queryDTO.enterpriseId"));
			System.out.println(element.elementText("width"));// 因爲沒有，所以輸出爲null。
		}
	}*/

	public static void main(String[] args) {
		try {
			Document dd = XmlReaderUtil.getInstance().readClassPathFile(
					"test.xml");
			Document d = XmlReaderUtil
					.getInstance()
					.readSystemPathFile(
							"D:/projects_diy2_branch_diyTheme/agent-web/src/main/resources/test.xml");
			Element e = d.getRootElement();
			Element ee = dd.getRootElement();
			System.out.println(e.getName());
			System.out.println(ee.getName());
			Element ele = XmlReaderUtil.getInstance().getEle(dd, "//data/mycontext");
			System.out.println(ele.getName());
		} catch (DocumentException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}