本篇介绍在java中，如何使用org.w3c.dom中的相关内容来操作XML文件。包括：
- 如何在内存中构建XML文件并写入磁盘；
- 如何从磁盘读取XML文件到内存；
- 如何添加注释，读取注释；
- 如何添加属性，读取属性；
- 如何添加子元素，读取子元素；
下面直接贴出样例代码：
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
public class XMLSample{
private static void writeXML(Document document, String filePath) {
TransformerFactory transFactory = TransformerFactory.newInstance();
Transformer transformer = null;
try {
String parent = new File(filePath).getParent();
File pDir = new File(parent);
if (!pDir.exists()) {
pDir.mkdirs();
}
OutputStream os = new FileOutputStream(new File(filePath));
transformer = transFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty(OutputKeys.ENCODING, "utf-8");
DOMSource source = new DOMSource();
source.setNode(document);
StreamResult result = new StreamResult();
result.setOutputStream(os);
transformer.transform(source, result);
os.flush();
} catch (TransformerConfigurationException e) {
e.printStackTrace();
} catch (TransformerException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private static Document readXML(String file) {
try {
// 得到DOM解析器的工厂实例
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
// 从DOM工厂中获得DOM解析器
DocumentBuilder dbBuilder = dbFactory.newDocumentBuilder();
// 把要解析的xml文档读入DOM解析器
Document doc = dbBuilder.parse(file);
return doc;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
public static void showXMLDetail() {
Document document = readXML(mapperFilePath);
// 获取标签名为"dataset"的元素
Node mapper = document.getElementsByTagName("dataset").item(0);
// 下面依次读取dataset元素的每个子元素，每个子元素的标签名字为node
for (int i = 0; i < mapper.getChildNodes().getLength(); i++) {
Node node = mapper.getChildNodes().item(i);
String s = item.getNodeName();
if(s.toLowerCase().equals("#comment")){
System.out.println("这是注释内容: "+node.getTextContent());
}else if(s.toLowerCase().equals("#text")){
System.out.println("呐，这是标签之外的文本: "+node.getTextContent());
}else if ("node".equals(s)) {
// 获取元素属性的值
String column = item.getAttributes().getNamedItem("column").getNodeValue();
String field = item.getAttributes().getNamedItem("property").getNodeValue();
}else{
// 其他的就不要了
}
}
}
public static void generateXML(){
try {
Element root;
Set<String> set = new HashSet<>();
set.add("node");
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder documentBuilder = null;
documentBuilder = factory.newDocumentBuilder();
Document document = documentBuilder.newDocument();
root = document.createElement("dataset");
document.appendChild(root);
set.forEach(p -> {
Element element = document.createElement(p);
element.setAttribte("column","haha");
element.setAttribte("property","heihei");
root.appendChild(element);
});
writeXML(document, "d:/allTables.xml");
} catch (ParserConfigurationException e) {
e.printStackTrace();
}
}
}Java操作XML（使用org.w3c.dom）
一、创建DOM
XMLBuilder.java
用于创建ＤＯＭ，Root结点
package rochoc.xml.oper;
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;
public class XmlBuilder
{
public XmlBuilder(String path)
{
this.path=path;
init();
}
public void init()
{
buildDocument();
buildRoot();
}
private void buildDocument()
{
DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
try
{
DocumentBuilder builder=factory.newDocumentBuilder();
logger.debug("Construct document builder success.");
doc=builder.parse(new File(path));
logger.debug("Build xml document success.");
}catch(ParserConfigurationException e)
{
logger.error("Construct document builder error:"+e);
}catch(SAXException e)
{
logger.error("Parse xml file error:"+e);
}catch(IOException e)
{
logger.error("Read xml file error:"+e);
}
}
private void buildRoot()
{
root=doc.getDocumentElement();
}
public Document getDoc()
{
return doc;
}
public void setDoc(Document doc)
{
this.doc = doc;
}
public String getPath()
{
return path;
}
public void setPath(String path)
{
this.path = path;
}
public Element getRoot()
{
return root;
}
public void setRoot(Element root)
{
this.root = root;
}
private String path=null;//xml文件路径
private Document doc=null;//xml文件对应的document
private Element root=null;//xml文件的根结点
private Logger logger=Logger.getLogger(getClass().getName());
}
二、查找，插入，删除，修改
XmlOper.java
用于操作ＸＭＬ文件，包括查找、新增、删除、修改结点
package rochoc.xml.oper;
import java.util.ArrayList;
import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class XmlOper
{
private XmlOper()
{
}
public static NodeList getNodeList(Element parent)
{
return parent.getChildNodes();
}
public static Element [] getElementsByName(Element parent,String name)
{
ArrayList resList=new ArrayList();
NodeList nl=getNodeList(parent);
for(int i=0;i<nl.getLength();i++)
{
Node nd=nl.item(i);
if(nd.getNodeName().equals(name))
{
resList.add(nd);
}
}
Element [] res=new Element [resList.size()];
for(int i=0;i<resList.size();i++)
{
res[0]=(Element)resList.get(i);
}
logger.debug(parent.getNodeName()+"'s children of "+name+
"'s num:"+res.length);
return res;
}
public static String getElementName(Element element)
{
return element.getNodeName();
}
public static String getElementValue(Element element)
{
NodeList nl=element.getChildNodes();
for(int i=0;i<nl.getLength();i++)
{
if(nl.item(i).getNodeType()==Node.TEXT_NODE)//是一个Text Node
{
logger.debug(element.getNodeName()+" has a Text Node.");
return element.getFirstChild().getNodeValue();
}
}
logger.error(element.getNodeName()+" hasn't a Text Node.");
return null;
}
public static String getElementAttr(Element element,String attr)
{
return element.getAttribute(attr);
}
public static void setElementValue(Element element,String val)
{
Node node=element.getOwnerDocument().createTextNode(val);
NodeList nl=element.getChildNodes();
for(int i=0;i<nl.getLength();i++)
{
Node nd=nl.item(i);
if(nd.getNodeType()==Node.TEXT_NODE)//是一个Text Node
{
nd.setNodeValue(val);
logger.debug("modify "+element.getNodeName()+"'s node value succe.");
return;
}
}
logger.debug("new "+element.getNodeName()+"'s node value succe.");
element.appendChild(node);
}
public static void setElementAttr(Element element,
String attr,String attrVal)
{
element.setAttribute(attr,attrVal);
}
public static void addElement(Element parent,Element child)
{
parent.appendChild(child);
}
public static void addElement(Element parent,String tagName)
{
Document doc=parent.getOwnerDocument();
Element child=doc.createElement(tagName);
parent.appendChild(child);
}
public static void addElement(Element parent,String tagName,String text)
{
Document doc=parent.getOwnerDocument();
Element child=doc.createElement(tagName);
setElementValue(child,text);
parent.appendChild(child);
}
public static void removeElement(Element parent,String tagName)
{
logger.debug("remove "+parent.getNodeName()+"'s children by tagName "+tagName+" begin...");
NodeList nl=parent.getChildNodes();
for(int i=0;i<nl.getLength();i++)
{
Node nd=nl.item(i);
if(nd.getNodeName().equals(tagName))
{
parent.removeChild(nd);
logger.debug("remove child '"+nd+"' success.");
}
}
logger.debug("remove "+parent.getNodeName()+"'s children by tagName "+tagName+" end.");
}
static Logger logger=Logger.getLogger("XmlOper");
}
三、新建XML文件
XmlCreater.java
用于创建ＸＭＬ文件
package rochoc.xml.oper;
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
public class XmlCreater
{
public XmlCreater(String path)
{
this.path=path;
init();
}
private void init()
{
DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
try
{
DocumentBuilder builder=factory.newDocumentBuilder();
doc=builder.newDocument();//新建DOM
}catch(ParserConfigurationException e)
{
logger.error("Parse DOM builder error:"+e);
}
}
public Element createRootElement(String rootTagName)
{
if(doc.getDocumentElement()==null)
{
logger.debug("create root element '"+rootTagName+"' success.");
Element root=doc.createElement(rootTagName);
doc.appendChild(root);
return root;
}
logger.warn("this dom's root element is exist,create fail.");
return doc.getDocumentElement();
}
public Element createElement(Element parent,String tagName)
{
Document doc=parent.getOwnerDocument();
Element child=doc.createElement(tagName);
parent.appendChild(child);
return child;
}
public Element createElement(Element parent,String tagName,String value)
{
Document doc=parent.getOwnerDocument();
Element child=doc.createElement(tagName);
XmlOper.setElementValue(child,value);
parent.appendChild(child);
return child;
}
public void createAttribute(Element parent,String attrName,String attrValue)
{
XmlOper.setElementAttr(parent,attrName,attrValue);
}
public void buildXmlFile()
{
TransformerFactory tfactory=TransformerFactory.newInstance();
try
{
Transformer transformer=tfactory.newTransformer();
DOMSource source=new DOMSource(doc);
logger.debug("New DOMSource success.");
StreamResult result=new StreamResult(new File(path));
logger.debug("New StreamResult success.");
transformer.setOutputProperty("encoding","GBK");
transformer.transform(source,result);
logger.debug("Build XML File '"+path+"' success.");
}catch(TransformerConfigurationException e)
{
logger.error("Create Transformer error:"+e);
}catch(TransformerException e)
{
logger.error("Transformer XML file error:"+e);
}
}
public Document getDoc()
{
return doc;
}
public void setDoc(Document doc)
{
this.doc = doc;
}
public String getPath()
{
return path;
}
public void setPath(String path)
{
this.path = path;
}
private Logger logger = Logger.getLogger(getClass().getName());
private Document doc=null;//新创建的DOM
private String path=null;//生成的XML文件绝对路径
}以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程网。
