java操作xml（sax，dom，jdom，dom4j）增删改查
1：DOM4J性能最好，连Sun的JAXM也在用DOM4J.目前许多开源项目中大量采用DOM4J，例如大名鼎鼎的Hibernate也用DOM4J来读取XML配置文件。如果不考虑可移植性，那就采用DOM4J.
2：JDOM和DOM在性能测试时表现不佳，在测试10M文档时内存溢出。在小文档情况下还值得考虑使用DOM和JDOM.虽然JDOM的开发者已经说明他们期望在正式发行版前专注性能问题，但是从性能观点来看，它确实没有值得推荐之处。另外，DOM仍是一个非常好的选择。DOM实现广泛应用于多种编程语言。它还是许多其它与XML相关的标准的基础，因为它正式获得W3C推荐（与基于非标准的Java模型相对），所以在某些类型的项目中可能也需要它（如在JavaScript中使用DOM）。
3：SAX表现较好，这要依赖于它特定的解析方式－事件驱动。一个SAX检测即将到来的XML流，但并没有载入到内存（当然当XML流被读入时，会有部分文档暂时隐藏在内存中）。
接下来我来展示以下用这四种方式处理xml的一个简单的例子，希望能给大家一些帮助。
1：要操作的xml文件：student.xml
<?xmlversion="1.0"encoding="UTF-8"?>
<students>
<student>
<name>TigerLee</name>
<age>26</age>
<sex>男</sex>
<address>北京海淀</address>
</student>
<student>
<name>Snow</name>
<age>24</age>
<sex>女</sex>
<address>山东</address>
</student>
</students>
2：处理xml的java类HandleXML.java
packagecom.tigerlee.xml;
importjava.io.File;
importjava.io.FileWriter;
importjava.io.Writer;
importjava.util.Iterator;
importjava.util.LinkedHashMap;
importjava.util.List;
importjava.util.Map;
importjava.util.Set;
importjava.util.Stack;
importjavax.xml.parsers.DocumentBuilder;
importjavax.xml.parsers.DocumentBuilderFactory;
importjavax.xml.transform.Transformer;
importjavax.xml.transform.TransformerFactory;
importjavax.xml.transform.dom.DOMSource;
importjavax.xml.transform.stream.StreamResult;
importorg.dom4j.Element;
importorg.dom4j.io.OutputFormat;
importorg.dom4j.io.SAXReader;
importorg.dom4j.io.XMLWriter;
importorg.w3c.dom.Document;
importorg.w3c.dom.Node;
importorg.w3c.dom.NodeList;
importorg.xml.sax.Attributes;
importorg.xml.sax.SAXException;
importorg.xml.sax.helpers.DefaultHandler;
/**
*
*在XML文档中实现增、删、改、查
*@authorTigerLee
*
*/
publicclassHandleXML{
/**
*采用DOM方式
*@authorTigerLee
*
*/
publicclassDOMForXml{
/**
*获得doc对象
*@paramfileName
*@return
*/
publicDocumentgetDocument(StringfileName){
Documentdocument=null;
try{
DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
DocumentBuilderbuilder=factory.newDocumentBuilder();
document=builder.parse(newFile(fileName));
}catch(Exceptione){
e.printStackTrace();
}
returndocument;
}
/**
*将改动持久到文件
*@paramdoc
*@paramdistFileName
*/
publicvoidmodifyFile(Documentdoc,StringdistFileName){
try{
TransformerFactorytf=TransformerFactory.newInstance();
Transformertfer=tf.newTransformer();
DOMSourcedsource=newDOMSource(doc);
StreamResultsr=newStreamResult(newFile("student.xml"));
tfer.transform(dsource,sr);
}catch(Exceptione){
e.printStackTrace();
}
}
/**
*解析
*@paramfileName
*/
publicvoidpaseXml(StringfileName){
Documentdocument=getDocument(fileName);
NodeListnodeList=document.getElementsByTagName("student");
for(inti=0;i<nodeList.getLength();i++){
StringBuildersb=newStringBuilder();
sb.append("姓名："+document.getElementsByTagName("name").item(i).getFirstChild().getNodeValue());
sb.append(",");
sb.append("年龄："+document.getElementsByTagName("age").item(i).getFirstChild().getNodeValue());
sb.append(",");
sb.append("性别："+document.getElementsByTagName("sex").item(i).getFirstChild().getNodeValue());
sb.append(",");
sb.append("地址："+document.getElementsByTagName("address").item(i).getFirstChild().getNodeValue());
System.out.println(sb.toString());
}
}
/**
*创建一个新的学生
*@paramname
*@paramage
*@paramsex
*@paramaddress
*/
publicvoidaddNewNode(Stringname,Stringage,Stringsex,Stringaddress){
try{
Documentdocument=getDocument("student.xml");
NodeListnodeList=document.getElementsByTagName("students");
//创建新的节点
NodestudentNode=document.createElement("student");
NodenameNode=document.createElement("name");
nameNode.appendChild(document.createTextNode(name));
NodeageNode=document.createElement("age");
ageNode.appendChild(document.createTextNode(age));
NodesexNode=document.createElement("sex");
sexNode.appendChild(document.createTextNode(sex));
NodeaddressNode=document.createElement("address");
addressNode.appendChild(document.createTextNode(address));
//添加节点
studentNode.appendChild(nameNode);
studentNode.appendChild(ageNode);
studentNode.appendChild(sexNode);
studentNode.appendChild(addressNode);
nodeList.item(0).appendChild(studentNode);
//此时真正的处理将新数据添加到文件中（磁盘）
TransformerFactorytf=TransformerFactory.newInstance();
Transformertfer=tf.newTransformer();
DOMSourcedsource=newDOMSource(document);
StreamResultsr=newStreamResult(newFile("student.xml"));
tfer.transform(dsource,sr);
}catch(Exceptione){
e.printStackTrace();
}
paseXml("student.xml");
}
/**
*删除一个节点
*@paramname
*/
publicvoiddeleteNode(Stringname){
Documentdocument=getDocument("student.xml");
NodeListnodeList=document.getElementsByTagName("name");
for(inti=0;i<nodeList.getLength();i++){
Stringvalue=nodeList.item(i).getFirstChild().getTextContent();
if(name!=null&&name.equalsIgnoreCase(value)){
NodeparentNode=nodeList.item(i).getParentNode();
document.getFirstChild().removeChild(parentNode);
}
}
modifyFile(document,"student.xml");
}
/**
*根据name修改某个节点的内容
*@paramname
*/
publicvoidupdateNode(Stringname){
Documentdocument=getDocument("student.xml");
NodeListnodeList=document.getElementsByTagName("name");
for(inti=0;i<nodeList.getLength();i++){
Stringvalue=nodeList.item(i).getFirstChild().getTextContent();
if(name!=null&&name.equalsIgnoreCase(value)){
NodeparentNode=nodeList.item(i).getParentNode();
NodeListnl=parentNode.getChildNodes();
for(intj=0;j<nl.getLength();j++){
StringmodifyNode=nl.item(j).getNodeName();
if(modifyNode.equalsIgnoreCase("age")){
nl.item(j).getFirstChild().setTextContent("25");
}
}
}
}
modifyFile(document,"student.xml");
}
}
/**
*采用SAX方式
*@authorTigerLee
*
*/
publicclassSAXForXmlextendsDefaultHandler{
privateStacktags=newStack();
privateMapcontents=newLinkedHashMap();
publicintcount=0;
@Override
publicvoidcharacters(char[]ch,intstart,intlength)
throwsSAXException{
Stringtag=(String)tags.peek();
if("name".equals(tag)){
Stringname=newString(ch,start,length);
contents.put("name"+count,name);
}
if("age".equals(tag)){
contents.put("age"+count,newString(ch,start,length));
}
if("sex".equals(tag)){
contents.put("sex"+count,newString(ch,start,length));
}
if("address".equals(tag)){
contents.put("address"+count,newString(ch,start,length));
}
}
@Override
publicvoidstartElement(Stringuri,StringlocalName,StringqName,
Attributesattributes)throwsSAXException{
if("student".equals(qName)){
count++;
}
tags.push(qName);
}
@Override
publicvoidendElement(Stringuri,StringlocalName,StringqName)
throwsSAXException{
tags.pop();
}
publicMapgetContents(){
returncontents;
}
}
/**
*采用JDOM方式
*@authorTigerLee
*
*/
publicclassJDOMForXml{
}
/**
*采用DOM4J方式
*@authorTigerLee
*
*/
publicclassDOM4JForXml{
/**
*获取doc对象（org.dom4j.Document）
*@paramfileName
*@return
*/
publicorg.dom4j.DocumentgetDocument(StringfileName){
SAXReadersr=newSAXReader();
org.dom4j.Documentdoc=null;
try{
doc=sr.read(newFile(fileName));
}catch(Exceptione){
e.printStackTrace();
}
returndoc;
}
/**
*将文件保存到硬盘
*@paramdoc
*@paramfileName
*/
publicvoidwriteToFile(org.dom4j.Documentdoc,StringfileName){
try{
Writerwriter=newFileWriter(fileName);
OutputFormatformat=OutputFormat.createPrettyPrint();
format.setEncoding("UTF-8");
XMLWriterxmlWriter=newXMLWriter(writer,format);
xmlWriter.write(doc);
xmlWriter.close();
System.out.println("文件已经钝化！");
}catch(Exceptione){
e.printStackTrace();
}
}
/**
*遍历xml文件输出节点值
*
*@paramfileName
*/
publicvoidreadXml(StringfileName){
org.dom4j.Documentdoc=getDocument(fileName);
ListnameList=doc.selectNodes("/students/student/name");
ListageList=doc.selectNodes("/students/student/age");
ListsexList=doc.selectNodes("/students/student/sex");
ListaddressList=doc.selectNodes("/students/student/address");
for(inti=0;i<nameList.size();i++){
StringBuildersb=newStringBuilder();
sb.append("name="+((Element)nameList.get(i)).getTextTrim());
sb.append(",age="+((Element)ageList.get(i)).getTextTrim());
sb.append(",sex="+((Element)sexList.get(i)).getTextTrim());
sb.append(",address="+((Element)addressList.get(i)).getTextTrim());
System.out.println(sb.toString());
}
}
/**
*根据姓名修改一个学生的信息
*@paramname
*@paramnewValue
*@paramfileName
*/
publicvoidupdateXml(Stringname,MapnewValue,StringfileName){
org.dom4j.Documentdoc=getDocument(fileName);
ListnameList=doc.selectNodes("/students/student/name");
Iteratoriterator=nameList.iterator();
while(iterator.hasNext()){
Elementelement=(Element)iterator.next();
if(name!=null&&name.equals(element.getText())){
Elementpe=element.getParent();
ListchildList=pe.elements();
for(inti=0;i<childList.size();i++){
IteratorvalueSet=newValue.entrySet().iterator();
while(valueSet.hasNext()){
Map.Entryentry=(Map.Entry)valueSet.next();
StringnodeName=((Element)childList.get(i)).getName();
Stringkey=entry.getKey().toString();
if(key!=null&&key.equals(nodeName)){
((Element)childList.get(i)).setText((String)entry.getValue());
}
}
}
}
}
writeToFile(doc,fileName);
}
}
}
3:接下来是测试的java文件TestXml.java
packagecom.tigerlee.xml;
importjava.io.File;
importjava.util.HashMap;
importjava.util.Iterator;
importjava.util.Map;
importjava.util.Set;
importjavax.xml.parsers.SAXParserFactory;
importorg.junit.Test;
publicclassTestXml{
@Test
publicvoidtestDomForXml(){
HandleXMLhandleXml=newHandleXML();
HandleXML.DOMForXmldomForXml=handleXml.newDOMForXml();
//解析
//domForXml.paseXml("student.xml");
//新增
//domForXml.addNewNode("Sun","20","Man","USA");
//删除
//domForXml.deleteNode("sun");
domForXml.updateNode("TigerLee");
}
@Test
publicvoidtestSAXForXml()throwsException{
HandleXMLhandleXml=newHandleXML();
HandleXML.SAXForXmlsaxForXml=handleXml.newSAXForXml();
SAXParserFactorysaxFactory=SAXParserFactory.newInstance();
javax.xml.parsers.SAXParsersp=saxFactory.newSAXParser();
sp.parse(newFile("student.xml"),saxForXml);
Mapcontents=saxForXml.getContents();
Iteratorkeys=contents.keySet().iterator();
while(keys.hasNext()){
Stringkey=(String)keys.next();
System.out.println(key+":"+contents.get(key));
}
}
@Test
publicvoidtestDom4jForXml(){
HandleXMLhandleXml=newHandleXML();
HandleXML.DOM4JForXmldom4j=handleXml.newDOM4JForXml();
//解析xml
dom4j.readXml("student.xml");
MapnewValue=newHashMap();
newValue.put("age","26");
dom4j.updateXml("TigerLee",newValue,"student.xml");
}
}
以上是自己总结的一些处理xml的方式，~~在处理xml的类中使用了内部类，测试类使用的是简单的单元测试方式。
例子中使用的jar包：
dom.jar
xercesImpl.jar
dom4j-1.6.1.jar
jaxen-1.1.1.jar