java操作xml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

<?xml version="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

package com.tigerlee.xml; 

import java.io.File; 
import java.io.FileWriter; 
import java.io.Writer; 
import java.util.Iterator; 
import java.util.LinkedHashMap; 
import java.util.List; 
import java.util.Map; 
import java.util.Set; 
import java.util.Stack; 

import javax.xml.parsers.DocumentBuilder; 
import javax.xml.parsers.DocumentBuilderFactory; 
import javax.xml.transform.Transformer; 
import javax.xml.transform.TransformerFactory; 
import javax.xml.transform.dom.DOMSource; 
import javax.xml.transform.stream.StreamResult; 

import org.dom4j.Element; 
import org.dom4j.io.OutputFormat; 
import org.dom4j.io.SAXReader; 
import org.dom4j.io.XMLWriter; 
import org.w3c.dom.Document; 
import org.w3c.dom.Node; 
import org.w3c.dom.NodeList; 
import org.xml.sax.Attributes; 
import org.xml.sax.SAXException; 
import org.xml.sax.helpers.DefaultHandler; 

/** 
* 
* 在XML文档中实现增、删、改、查 
* @author TigerLee 
* 
*/ 
public class HandleXML { 

/** 
* 采用DOM方式 
* @author TigerLee 
* 
*/ 
public class DOMForXml{ 
/** 
* 获得doc对象 
* @param fileName 
* @return 
*/ 
public Document getDocument(String fileName){ 
Document document = null; 
try{ 
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); 
DocumentBuilder builder = factory.newDocumentBuilder(); 
document = builder.parse(new File(fileName)); 

}catch(Exception e){ 
e.printStackTrace(); 
} 

return document; 
} 
/** 
* 将改动持久到文件 
* @param doc 
* @param distFileName 
*/ 
public void modifyFile(Document doc,String distFileName){ 
try{ 
TransformerFactory tf = TransformerFactory.newInstance(); 
Transformer tfer = tf.newTransformer(); 
DOMSource dsource = new DOMSource(doc); 
StreamResult sr = new StreamResult(new File("student.xml")); 
tfer.transform(dsource, sr); 
}catch(Exception e){ 
e.printStackTrace(); 
} 

} 
/** 
* 解析 
* @param fileName 
*/ 
public void paseXml(String fileName){ 
Document document = getDocument(fileName); 
NodeList nodeList = document.getElementsByTagName("student"); 
for(int i=0;i<nodeList.getLength();i++){ 
StringBuilder sb = new StringBuilder(); 
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 
* @param name 
* @param age 
* @param sex 
* @param address 
*/ 
public void addNewNode(String name,String age,String sex,String address){ 
try{ 
Document document = getDocument("student.xml"); 
NodeList nodeList = document.getElementsByTagName("students"); 
//创建新的节点 
Node studentNode = document.createElement("student"); 
Node nameNode = document.createElement("name"); 
nameNode.appendChild(document.createTextNode(name)); 
Node ageNode = document.createElement("age"); 
ageNode.appendChild(document.createTextNode(age)); 
Node sexNode = document.createElement("sex"); 
sexNode.appendChild(document.createTextNode(sex)); 
Node addressNode = 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） 
TransformerFactory tf = TransformerFactory.newInstance(); 
Transformer tfer = tf.newTransformer(); 
DOMSource dsource = new DOMSource(document); 
StreamResult sr = new StreamResult(new File("student.xml")); 
tfer.transform(dsource, sr); 
}catch(Exception e){ 
e.printStackTrace(); 
} 

paseXml("student.xml"); 
} 
/** 
* 删除一个节点 
* @param name 
*/ 
public void deleteNode(String name){ 
Document document = getDocument("student.xml"); 

NodeList nodeList = document.getElementsByTagName("name"); 
for(int i=0;i<nodeList.getLength();i++){ 
String value = nodeList.item(i).getFirstChild().getTextContent(); 
if(name!=null && name.equalsIgnoreCase(value)){ 
Node parentNode = nodeList.item(i).getParentNode(); 
document.getFirstChild().removeChild(parentNode); 
} 
} 
modifyFile(document,"student.xml"); 
} 
/** 
* 根据name修改某个节点的内容 
* @param name 
*/ 
public void updateNode(String name){ 

Document document = getDocument("student.xml"); 
NodeList nodeList = document.getElementsByTagName("name"); 
for(int i=0;i<nodeList.getLength();i++){ 
String value = nodeList.item(i).getFirstChild().getTextContent(); 
if(name!=null && name.equalsIgnoreCase(value)){ 
Node parentNode = nodeList.item(i).getParentNode(); 
NodeList nl = parentNode.getChildNodes(); 
for(int j=0;j<nl.getLength();j++){ 
String modifyNode= nl.item(j).getNodeName(); 
if(modifyNode.equalsIgnoreCase("age")){ 
nl.item(j).getFirstChild().setTextContent("25"); 
} 
} 
} 
} 
modifyFile(document,"student.xml"); 
} 


} 
/** 
* 采用SAX方式 
* @author TigerLee 
* 
*/ 
public class SAXForXml extends DefaultHandler{ 
private Stack tags = new Stack(); 
private Map contents = new LinkedHashMap(); 
public int count = 0; 
@Override 
public void characters(char[] ch, int start, int length) 
throws SAXException { 
String tag = (String)tags.peek(); 

if("name".equals(tag)){ 
String name = new String(ch,start,length); 
contents.put("name"+count,name); 
} 
if("age".equals(tag)){ 
contents.put("age"+count,new String(ch,start,length)); 
} 
if("sex".equals(tag)){ 
contents.put("sex"+count,new String(ch,start,length)); 
} 
if("address".equals(tag)){ 
contents.put("address"+count,new String(ch,start,length)); 
} 
} 

@Override 
public void startElement(String uri, String localName, String qName, 
Attributes attributes) throws SAXException { 
if("student".equals(qName)){ 
count++; 
} 
tags.push(qName); 
} 

@Override 
public void endElement(String uri, String localName, String qName) 
throws SAXException { 
tags.pop(); 
} 

public Map getContents(){ 
return contents; 
} 
} 

/** 
* 采用JDOM方式 
* @author TigerLee 
* 
*/ 
public class JDOMForXml{ 

} 

/** 
* 采用DOM4J方式 
* @author TigerLee 
* 
*/ 
public class DOM4JForXml{ 
/** 
* 获取doc对象（org.dom4j.Document） 
* @param fileName 
* @return 
*/ 
public org.dom4j.Document getDocument(String fileName){ 
SAXReader sr = new SAXReader(); 
org.dom4j.Document doc = null; 
try { 

doc = sr.read(new File(fileName)); 

} catch (Exception e) { 

e.printStackTrace(); 
} 
return doc; 
} 
/** 
* 将文件保存到硬盘 
* @param doc 
* @param fileName 
*/ 
public void writeToFile(org.dom4j.Document doc,String fileName){ 
try { 
Writer writer = new FileWriter(fileName); 
OutputFormat format = OutputFormat.createPrettyPrint(); 
format.setEncoding("UTF-8"); 
XMLWriter xmlWriter = new XMLWriter(writer, format); 
xmlWriter.write(doc); 
xmlWriter.close(); 
System.out.println(" 文件已经钝化！"); 
} catch (Exception e) { 

e.printStackTrace(); 
} 
} 

/** 
* 遍历xml文件输出节点值 
* 
* @param fileName 
*/ 
public void readXml(String fileName){ 
org.dom4j.Document doc = getDocument(fileName); 
List nameList = doc.selectNodes("/students/student/name"); 
List ageList = doc.selectNodes("/students/student/age"); 
List sexList = doc.selectNodes("/students/student/sex"); 
List addressList = doc.selectNodes("/students/student/address"); 
for(int i=0;i<nameList.size();i++){ 
StringBuilder sb = new StringBuilder(); 
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 
* @param name 
* @param newValue 
* @param fileName 
*/ 
public void updateXml(String name,Map newValue,String fileName){ 
org.dom4j.Document doc = getDocument(fileName); 
List nameList = doc.selectNodes("/students/student/name"); 
Iterator iterator = nameList.iterator(); 

while(iterator.hasNext()){ 
Element element = (Element)iterator.next(); 

if(name!=null && name.equals(element.getText())){ 
Element pe = element.getParent(); 
List childList = pe.elements(); 
for(int i=0;i<childList.size();i++){ 
Iterator valueSet = newValue.entrySet().iterator(); 
while(valueSet.hasNext()){ 
Map.Entry entry = (Map.Entry)valueSet.next(); 
String nodeName = ((Element)childList.get(i)).getName(); 
String key = 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

package com.tigerlee.xml; 

import java.io.File; 
import java.util.HashMap; 
import java.util.Iterator; 
import java.util.Map; 
import java.util.Set; 

import javax.xml.parsers.SAXParserFactory; 

import org.junit.Test; 


public class TestXml{ 

@Test 
public void testDomForXml(){ 

HandleXML handleXml = new HandleXML(); 
HandleXML.DOMForXml domForXml = handleXml.new DOMForXml(); 
//解析 
//domForXml.paseXml("student.xml"); 
// 新增 
//domForXml.addNewNode("Sun", "20", "Man", "USA"); 
//删除 
//domForXml.deleteNode("sun"); 
domForXml.updateNode("TigerLee"); 
} 
@Test 
public void testSAXForXml() throws Exception{ 
HandleXML handleXml = new HandleXML(); 
HandleXML.SAXForXml saxForXml = handleXml.new SAXForXml(); 
SAXParserFactory saxFactory = SAXParserFactory.newInstance(); 
javax.xml.parsers.SAXParser sp = saxFactory.newSAXParser(); 
sp.parse(new File("student.xml"), saxForXml); 
Map contents = saxForXml.getContents(); 
Iterator keys = contents.keySet().iterator(); 
while(keys.hasNext()){ 
String key = (String)keys.next(); 
System.out.println(key+":"+contents.get(key)); 
} 
} 
@Test 
public void testDom4jForXml(){ 
HandleXML handleXml = new HandleXML(); 
HandleXML.DOM4JForXml dom4j = handleXml.new DOM4JForXml(); 
//解析xml 
dom4j.readXml("student.xml"); 

Map newValue = new HashMap(); 
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

评论

1 楼 jamesji 2012-01-06  

Try XML library Simple or XStream, they are way better than DOM or SAX.