DOM4J操作XML(包含封装和解析)

DOM4J操作XML(包含封装和解析)

先来看看dom4j中对应XML的DOM树建立的继承关系



针对于XML标准定义，对应于图2-1列出的内容，dom4j提供了以下实现：



下面给出一个具体事例:

package com.iboxpay.settlement.gateway.common.util;

import java.io.IOException;

import java.io.StringReader;

import java.io.StringWriter;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.DocumentHelper;

import org.dom4j.Element;

import org.dom4j.io.OutputFormat;

import org.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

import com.iboxpay.settlement.gateway.ccb.Constant;

import com.iboxpay.settlement.gateway.common.exception.PackMessageException;

import com.iboxpay.settlement.gateway.common.exception.ParseMessageException;

/**

* DOM4j工具类

* @author caolipeng

*/

public class DomUtil {

/**

* 添加孩子节点元素

* @param parent 父节点

* @param childName 孩子节点名称

* @param childValue 孩子节点值

* @return 新增节点

*/

public static Element addChild(Element parent, String childName,

String childValue) {

Element child = parent.addElement(childName);//添加节点元素

child.setText(childValue == null ? "" : childValue); //为元素设值

return child;

}

/**

* DOM4j的Document对象转为XML报文串

* @param document

* @param charset

* @return 经过解析后的xml字符串

*/

public static String documentToString(Document document,String charset) {

StringWriter stringWriter = new StringWriter();

OutputFormat format = OutputFormat.createPrettyPrint();//获得格式化输出流

format.setEncoding(charset);//设置字符集,默认为UTF-8

XMLWriter xmlWriter = new XMLWriter(stringWriter, format);//写文件流

try {

xmlWriter.write(document);

xmlWriter.flush();

xmlWriter.close();

} catch (IOException e) {

throw new RuntimeException(e);

}

return stringWriter.toString();

}

/**

* 去掉声明头的(即<?xml...?>去掉)

* @param document

* @param charset

* @return

*/

public static String documentToStringNoDeclaredHeader(Document document,String charset) {

String xml = documentToString(document, charset);

return xml.replaceFirst("\\s*<[^<>]+>\\s*", "");

}

/**

* 解析XML为Document对象

* @param xml 被解析的XMl

* @return Document

* @throws ParseMessageException

*/

public final static Element parseXml(String xml)throws ParseMessageException{

StringReader sr = new StringReader(xml);

SAXReader saxReader = new SAXReader();

Document document;

try {

document = saxReader.read(sr);

} catch (DocumentException e) {

throw new ParseMessageException(e);

}

Element rootElement = document.getRootElement();

return rootElement;

}

public final static String getText(Element e, String tag){

Element _e = e.element(tag);

if(_e != null)

return _e.getText();

else

return null;

}

public final static String getTextTrim(Element e, String tag){

Element _e = e.element(tag);

if(_e != null)

return _e.getTextTrim();

else

return null;

}

/**

* 获取节点值.节点必须不能为空，否则抛错

* @param parent

* @param tag

* @return

* @throws ParseMessageException

*/

public final static String getTextTrimNotNull(Element parent, String tag) throws ParseMessageException{

Element e = parent.element(tag);

if(e == null)

throw new ParseMessageException(parent.getName() + " -> " + tag + " 节点为空.");

else

return e.getTextTrim();

}

/**

* 节点必须不能为空，否则抛错

* @param parent

* @param tag

* @return

* @throws ParseMessageException

*/

public final static Element elementNotNull(Element parent, String tag) throws ParseMessageException{

Element e = parent.element(tag);

if(e == null)

throw new ParseMessageException(parent.getName() + " -> " + tag + " 节点为空.");

else

return e;

}

public static void main(String[] args) throws PackMessageException, ParseMessageException {

Document document = DocumentHelper.createDocument();

document.setXMLEncoding("GB2312");

Element root = document.addElement("TX");

DomUtil.addChild(root, "REQUEST_SN", "bankBatchSeqId");

DomUtil.addChild(root, "CUST_ID", "cust_id");

DomUtil.addChild(root, "USER_ID", "user_id");

DomUtil.addChild(root, "PASSWORD", "password");

DomUtil.addChild(root, "TX_CODE", "txCode");

DomUtil.addChild(root, "LANGUAGE", "CN");

Element tx_info = root.addElement(Constant.TX_INFO);

DomUtil.addChild(tx_info, Constant.REQUEST_SN1, "request_sn1");

String xml = DomUtil.documentToStringNoDeclaredHeader(root.getDocument(), "GBK");

System.out.println(xml);

root = parseXml(xml);

System.out.println(root.element("TX_INFO").elementText("REQUEST_SN1"));

}

}

主函数测试结果为:

<TX>

<REQUEST_SN>bankBatchSeqId</REQUEST_SN>

<CUST_ID>cust_id</CUST_ID>

<USER_ID>user_id</USER_ID>

<PASSWORD>password</PASSWORD>

<TX_CODE>txCode</TX_CODE>

<LANGUAGE>CN</LANGUAGE>

<TX_INFO>

<REQUEST_SN1>request_sn1</REQUEST_SN1>

</TX_INFO>

</TX>

request_sn1

博客参考文献:http://www.cnblogs.com/macula/archive/2011/07/27/2118003.html