DocumentHelper和SAXReader解析XML字符串

最近在看湖北中烟OA门户的项目，中烟门户里面解析XML文档使用的是DocumentHelper，之前做的智能导航项目里面解析XML使用的是SAXReader，很好奇它们有什么区别，于是就查资料将两者的用法简单总结了一下。

SAXReader用法示例

package com.eway.signature.action;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import javax.servlet.ServletRequest;import javax.servlet.http.HttpServletRequest;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.DocumentHelper;import org.dom4j.Element;import org.dom4j.io.SAXReader;public class UploadFile{    private static Log logger = LogFactory.getLog(UploadFile.class);    //要上传的配置文件的路径    static String uploadCfgFile = "WEB-INF/conf/uploadfile.xml";    Document uploadDocument;//文档对象实体    Map uploadMap = new HashMap();    /**     * 获取配置文件的绝对路径     * @param request     * @return     */    private String getUploadCfgFilePath(ServletRequest request){        return ((HttpServletRequest) request).getSession().getServletContext().getRealPath("uploadCfgFile");    }    /**     * 初始化配置文件     * @param request     * @return     */    private Document initUploadCfgDocument(ServletRequest request){        SAXReader saxReader = new SAXReader();        try {            //得到指定文件，以流的形式对文件进行序列化            FileInputStream fis = new FileInputStream(getUploadCfgFilePath(request));            uploadDocument = (Document) saxReader.read(fis);        } catch (FileNotFoundException e) {            logger.debug(e);        } catch (DocumentException e) {            logger.debug(e);        }        return uploadDocument;    }    /**     * 获取配置文件     * @param request     * @return     */    private Document getUploadCfgDocument(ServletRequest request){        if (this.uploadDocument == null) {            this.uploadDocument = initUploadCfgDocument(request);        }        return this.uploadDocument;    }    /**     * 获取某个指定ticket节点的配置属性     * @param request     * @return     */    private Map getUploadMap(ServletRequest request){        Document uploadDocument = getUploadCfgDocument(request);        //得到XML的根节点(message)        Element root = uploadDocument.getRootElement();        Iterator tickets = root.element("body").element("ticketNotify").elementIterator();        //获取ticketNotify节点下所有的ticket节点的配置属性，并将其放到Map中        while (tickets.hasNext()) {            Element ticket = (Element) tickets.next();            uploadMap.put("id", ticket.attributeValue("id"));            uploadMap.put("dealTime", ticket.attributeValue("dealTime"));            uploadMap.put("status", ticket.attributeValue("status"));        }        //Element.asXML方法，获得包括该标签的所有XML数据//      System.out.println(root.element("body").asXML());        return uploadMap;    }}

DocumentHelper的用法示例

package com.eway.signature.action;import java.io.BufferedReader;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStreamReader;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import javax.servlet.ServletRequest;import javax.servlet.http.HttpServletRequest;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.DocumentHelper;import org.dom4j.Element;public class UploadFile{    private static Log logger = LogFactory.getLog(UploadFile.class);    //要上传的配置文件的路径    static String uploadCfgFile = "WEB-INF/conf/uploadfile.xml";    Document uploadDocument;//文档对象实体    Map uploadMap = new HashMap();    /**     * 获取配置文件的绝对路径     * @param request     * @return     */    private String getUploadCfgFilePath(ServletRequest request){        return ((HttpServletRequest) request).getSession().getServletContext().getRealPath("uploadCfgFile");    }    /**     * 获取配置文件     * @param request     * @return     */    private Document getUploadCfgDocument(ServletRequest request){        String sText;        StringBuffer sb = new StringBuffer();        try {            //得到指定文件，以流的形式对文件进行序列化            BufferedReader br = new BufferedReader(                    new InputStreamReader(new FileInputStream(getUploadCfgFilePath(request))));            for (;;) {                sText = br.readLine();//一行一行的读取数据                if(sText == null){                    break;                }                sb.append(sText);            }            uploadDocument = DocumentHelper.parseText(sb.toString());        } catch (FileNotFoundException e) {            logger.debug(e);        } catch (DocumentException e) {            logger.debug(e);        } catch (IOException e) {            logger.debug(e);        }        return uploadDocument;    }    /**     * 获取某个指定ticket节点的配置属性     * @param request     * @return     */    private Map getUploadMap(ServletRequest request){        Document document = getUploadCfgDocument(request);        //获取根节点        Element root = document.getRootElement();        Iterator tickets = root.element("body").element("ticketNotify").elementIterator();        //获取ticketNotify节点下所有的ticket节点的配置属性，并将其放到Map中        while (tickets.hasNext()) {            Element ticket = (Element) tickets.next();            uploadMap.put("id", ticket.attributeValue("id"));            uploadMap.put("dealTime", ticket.attributeValue("dealTime"));            uploadMap.put("status", ticket.attributeValue("status"));        }        //Element.asXML方法，获得包括该标签的所有XML数据//      System.out.println(root.element("body").asXML());        return uploadMap;    }}

更多使用请参看DocumentHelper的在线API：

http://dom4j.sourceforge.net/dom4j-1.6.1/apidocs/org/dom4j/DocumentHelper.html#createAttribute%28org.dom4j.Element,%20org.dom4j.QName,%20java.lang.String%29

SAXReader可以直接使用read()方法将一个文件输入流转换成Document对象；而DocumentHelper不能直接操作文件输入流，只能使用parseText()方法将string字符串解析成Document对象，所以必须先将文件输入流写到String字符串中，再由DocumentHelper去解析。

更多使用继续发现中~