采用VTD-XML开源工具解析XML(一)
1.VTDGen是执行解析功能的类的名字

2.解析后,你可以得到VTDGen的一个实例,用它可以遍历整颗树.

3.AutoPilot是是XPath和节点遍历的包装类

基于指针的模型：仅有一个指针是可能的.解析后,指针位于根节点.你可以用一个全局堆栈来记下这个指针的位置.

无状态XPath估算：除非节点是空的,否则VTD-XM的Xpath赋值一次将返回一个节点.AutoPilot类的实例像一只魔术手,它通过XPath表达式在XMl树中移动指针.

一、解析---采用selectXpath的方式解xml文件

package org.dihua.util.xmlparse;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import com.ximpleware.AutoPilot;
import com.ximpleware.BookMark;
import com.ximpleware.NavException;
import com.ximpleware.VTDGen;
import com.ximpleware.VTDNav;
import com.ximpleware.XPathEvalException;
import com.ximpleware.XPathParseException;

public class ParseXmlBase {

public List getObjectFromXml(String FileName,String SelectPath,int count)
throwsXPathParseException,XPathEvalException,NavException {
List tablist = newArrayList();
//初始化 VTD 执行 触发器
VTDGen vg = new VTDGen();
int i;
//根据xpath装入xml文件
AutoPilot ap = newAutoPilot();
//SelectPath如: 根节点/子节点根据xml的层级设置合适的路径深度
ap.selectXPath(SelectPath);
//节点位置以单例模式装入记忆坐标
BookMark bm = newBookMark();
//装入要解析的文件返回是否解析成功
if (vg.parseFile(FileName,false)) {
//
VTDNav vn =vg.getNav();
bm.bind(vn);
ap.bind(vn);

while ((i= ap.evalXPath()) != -1) {
//获得tab 节点集
XmlObjectListxolist = new XmlObjectList();
xolist.setName(vn.toString(vn.getAttrVal("name")));
xolist.setReadonly(vn.toString(vn.getAttrVal("readonly")));
xolist.setDesc(vn.toString(vn.getAttrVal("desc")));
tablist.add(xolist);

xolist.setTabList(tablist);

bm.recordCursorPosition();// equivalent to vn.push();//这个地方很重要不刷新的话第一层就不能全部循环出来。*********
//get to the first child
XmlFieldObjectxfo = new XmlFieldObject();
Listxfolist = new ArrayList();
if(vn.toElement(VTDNav.FIRST_CHILD,"field")) {
intj = vn.getText();
if(j != -1)
xfo.setName(vn.toString(vn.getAttrVal("name")));
xfo.setReadonly(vn.toString(vn.getAttrVal("readonly")));
xfo.setDesc(vn.toString(vn.getAttrVal("desc")));
xfolist.add(xfo);
}
for(int s = 0; s < count; s++) {
XmlFieldObjectxfso = new XmlFieldObject();
if(vn.toElement(VTDNav.NEXT_SIBLING)) {
intj = vn.getText();
if(j != -1)
xfso.setName(vn.toString(vn.getAttrVal("name")));
xfso.setReadonly(vn.toString(vn.getAttrVal("readonly")));
xfso.setDesc(vn.toString(vn.getAttrVal("desc")));
xfolist.add(xfso);
}
}
//将filelis装载到tab对象
xolist.setFileList(xfolist);
bm.setCursorPosition();//这个地方很重要不刷新的话第一层就不能全部循环出来。********
}
//这句的意思应该是重设xpath
ap.resetXPath();
}

return tablist;
}

public static void main(String[] args) throwsXPathParseException,
XPathEvalException,NavException {
// TODO Auto-generated methodstub
ParseXmlBase pxb = newParseXmlBase();
List list =pxb.getObjectFromXml(
"C:/work/workspaces/vtdtest/src/com/mytest/test1.xml",
"/page/tab",13);

XmlObjectList xolistss =null;

List listf = newArrayList();
HashMap tabmap = newHashMap();
HashMap tabmapq = newHashMap();
for (int sf = 0; sf <list.size(); sf++) {
xolistss =(XmlObjectList) list.get(sf);
//第一层输出tab结果集
System.out.println("name...name...."+ xolistss.getName() + " "
+xolistss.getReadonly() + " " + xolistss.getDesc());
listf =xolistss.getFileList();
tabmap.put(xolistss.getName(),xolistss.getReadonly());
tabmapq.put(xolistss.getName(),xolistss.getDesc());

XmlFieldObjectxfos = null;
for (int fl =0; fl < listf.size(); fl++) {
xfos= (XmlFieldObject) listf.get(fl);
//第二层输出file结果集
System.out.println("" + xfos.getName() + " "
+xfos.getReadonly() + " " +xfos.getDesc());
}
}
System.out.println("sssss"+tabmap+""+tabmapq);
}

}

二、针对某个具体的值进行修改
package org.dihua.util.xmlparse;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.HashMap;

import com.ximpleware.AutoPilot;
import com.ximpleware.BookMark;
import com.ximpleware.NavException;
import com.ximpleware.VTDGen;
import com.ximpleware.VTDNav;
import com.ximpleware.XPathEvalException;
import com.ximpleware.XPathParseException;

public class ModifyXmlFile {

public void ModifyXmlFilePart(StringfileName,String FieldName,String changeContent) throwsXPathParseException,NavException,FileNotFoundException{
VTDGen vg = new VTDGen();
int i;
AutoPilot ap = newAutoPilot();
ap.selectXPath("/page/tab");
BookMark bm = newBookMark();
System.out.println("sdfadsfds");
if (vg.parseFile(fileName,false)) {
VTDNav vn =vg.getNav();
bm.bind(vn);
ap.bind(vn);

while ((i= ap.evalXPath()) != -1) {
System.out.println("aaa...."
+vn.toString(vn.getAttrVal("name")));
bm.recordCursorPosition();// equivalent to vn.push();此段将不能循环后续的tab节点的多组
if(vn.toElement(VTDNav.FIRST_CHILD,"field")) {
do{
intj = vn.getText();
StringfieldName=vn.toString(vn.getAttrVal("name"));
if(j != -1)
System.out.println(vn.toString(vn.getAttrVal("name")));
//定位修改位置
if(fieldName.equals(FieldName)){
System.out.println("fieldName..."+fieldName);
int ni = vn.getAttrVal("desc");
updateXmlPart(ni,vn,fileName,changeContent);
}
}while (vn.toElement(VTDNav.NEXT_SIBLING));
}
bm.setCursorPosition();//此段将不能循环后续的tab节点的多组
}
//这句的意思应该是重设xpath
ap.resetXPath();
}
}

public synchronized void updateXmlPart(int j,VTDNav vn,String fileName,String changeContent) throwsFileNotFoundException {
//File fo = newFile("C:/work/workspaces/vtdtest/src/com/mytest/test5.xml");
File fo=newFile(fileName);
FileOutputStream fos = newFileOutputStream(fo);
// 进行定位修改
if (j != -1) {
// Get thestarting offset of "1999-10-21"
int os1 =vn.getTokenOffset(j);
// Get theending offset of "1999-10-21"
int os2 =vn.getTokenOffset(j) + vn.getTokenLength(j);
// Get thetotal number of bytes of XML
int os3 =vn.getXML().length();

byte[] xml= vn.getXML().getBytes();
// Writeeverything before "1999-10-21"
try {
fos.write(xml,os1);
} catch(IOException e) {
//TODO Auto-generated catch block
e.printStackTrace();
}
// Write"2006-6-17"
try {
fos.write(changeContent.getBytes());
} catch(IOException e) {
//TODO Auto-generated catch block
e.printStackTrace();
}
// Writeeverything after
try {
fos.write(xml,os2,os3 - os2);
} catch(IOException e) {
//TODO Auto-generated catch block
e.printStackTrace();
}
try {
fos.close();
} catch(IOException e) {
//TODO Auto-generated catch block
e.printStackTrace();
}
//修改完毕
}
}



public static void main(String[] args) throwsXPathParseException,FileNotFoundException {
// TODO Auto-generated methodstub
ModifyXmlFile mxfp = newModifyXmlFile();
StringfileName="c:/tests.xml";
mxfp.ModifyXmlFilePart(fileName,"field1-2","testss");
}

}

定位修改

UpdateXmlFile.java 47---48行

AutoPilot ap = new AutoPilot(vn);
XMLModifier xm = new XMLModifier(vn);
//具体某个值时进行动作.
ap.selectXPath("/page/tab/field[@name='tab2']");
int i = -1;
while ((i = ap.evalXPath()) != -1) {

xm.remove();
xm.insertBeforeElement("<field name=\"tab2\"readonly=\"显示\" desc=\"扩展信息\"></field>");
}

UpdateXmlFile.java 106行开始部分
//进行定位修改
int j = vn.getAttrVal("name");定位根据此值得到标记指针所在位置

if (j != -1) {

// Get the starting offset of "1999-10-21" int os1 = vn.getTokenOffset(j); // Get the ending offset of "1999-10-21" int os2 = vn.getTokenOffset(j) + vn.getTokenLength(j); // Get the total number of bytes of XML int os3 = vn.getXML().length(); byte[] xml = vn.getXML().getBytes(); // Write everything before "1999-10-21" fos.write(xml,os1); // Write "2006-6-17" fos.write("2006-6-17".getBytes()); // Write everything after fos.write(xml,os3 - os2); fos.close(); //修改完毕 }