java解析xml的几种方式
第一种:DOM。
DOM的全称是Document Object 
Model,也即文档对象模型。在应用程序中,基于DOM的XML分析器将一个XML文档转换成一个对象模型的集合(通常称DOM树),应用程序正是通过
对这个对象模型的操作,来实现对XML文档数据的操作。通过DOM接口,应用程序可以在任何时候访问XML文档中的任何一部分数据,因此,这种利用DOM
接口的机制也被称作随机访问机制。
DOM接口提供了一种通过分层对象模型来访问XML文档信息的方式,这些分层对象模型依据XML的文档
结构形成了一棵节点树。无论XML文档中所描述的是什么类型的信息,即便是制表数据、项目列表或一个文档,利用DOM所生成的模型都是节点树的形式。也就
是说,DOM强制使用树模型来访问XML文档中的信息。由于XML本质上就是一种分层结构,所以这种描述方法是相当有效的。
DOM树所提
供的随机访问方式给应用程序的开发带来了很大的灵活性,它可以任意地控制整个XML文档中的内容。然而,由于DOM分析器把整个XML文档转化成DOM树
放在了内存中,因此,当文档比较大或者结构比较复杂时,对内存的需求就比较高。而且,对于结构复杂的树的遍历也是一项耗时的操作。所以,DOM分析器对机
器性能的要求比较高,实现效率不十分理想。不过,由于DOM分析器所采用的树结构的思想与XML文档的结构相吻合,同时鉴于随机访问所带来的方便,因此,DOM分析器还是有很广泛的使用价值的。
- import java.io.File;
 - import javax.xml.parsers.DocumentBuilder;
 - import javax.xml.parsers.DocumentBuilderFactory;
 - import org.w3c.dom.Document;
 - import org.w3c.dom.Element;
 - import org.w3c.dom.NodeList;
 - public class DomTest1
 - {
 - public static void main(String[] args) throws Exception
 - {
 - // step 1: 获得dom解析器工厂(工作的作用是用于创建具体的解析器)
 - DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
 - // System.out.println("class name: " + dbf.getClass().getName());
 - // step 2:获得具体的dom解析器
 - DocumentBuilder db = dbf.newDocumentBuilder();
 - // System.out.println("class name: " + db.getClass().getName());
 - // step3: 解析一个xml文档,获得Document对象(根结点)
 - Document document = db.parse(new File("candidate.xml"));
 - NodeList list = document.getElementsByTagName("PERSON");
 - for(int i = 0; i < list.getLength(); i++)
 - {
 - Element element = (Element)list.item(i);
 - String content = element.getElementsByTagName("NAME").item(0).getFirstChild().getNodeValue();
 - System.out.println("name:" + content);
 - content = element.getElementsByTagName("ADDRESS").item(0).getFirstChild().getNodeValue();
 - System.out.println("address:" + content);
 - content = element.getElementsByTagName("TEL").item(0).getFirstChild().getNodeValue();
 - System.out.println("tel:" + content);
 - content = element.getElementsByTagName("FAX").item(0).getFirstChild().getNodeValue();
 - System.out.println("fax:" + content);
 - content = element.getElementsByTagName("EMAIL").item(0).getFirstChild().getNodeValue();
 - System.out.println("email:" + content);
 - System.out.println("--------------------------------------");
 - }
 - }
 - }
 
- import java.io.File;
 - import javax.xml.parsers.DocumentBuilder;
 - import javax.xml.parsers.DocumentBuilderFactory;
 - import org.w3c.dom.Attr;
 - import org.w3c.dom.Comment;
 - 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;
 - /**
 - * 使用递归解析给定的任意一个xml文档并且将其内容输出到命令行上
 - * @author zhanglong
 - *
 - */
 - public class DomTest3
 - {
 - public static void main(String[] args) throws Exception
 - {
 - DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
 - DocumentBuilder db = dbf.newDocumentBuilder();
 - Document doc = db.parse(new File("student.xml"));
 - //获得根元素结点
 - Element root = doc.getDocumentElement();
 - parseElement(root);
 - }
 - private static void parseElement(Element element)
 - {
 - String tagName = element.getNodeName();
 - NodeList children = element.getChildNodes();
 - System.out.print("<" + tagName);
 - //element元素的所有属性所构成的NamedNodeMap对象,需要对其进行判断
 - NamedNodeMap map = element.getAttributes();
 - //如果该元素存在属性
 - if(null != map)
 - {
 - for(int i = 0; i < map.getLength(); i++)
 - {
 - //获得该元素的每一个属性
 - Attr attr = (Attr)map.item(i);
 - String attrName = attr.getName();
 - String attrValue = attr.getValue();
 - System.out.print(" " + attrName + "=\"" + attrValue + "\"");
 - }
 - }
 - System.out.print(">");
 - for(int i = 0; i < children.getLength(); i++)
 - {
 - Node node = children.item(i);
 - //获得结点的类型
 - short nodeType = node.getNodeType();
 - if(nodeType == Node.ELEMENT_NODE)
 - {
 - //是元素,继续递归
 - parseElement((Element)node);
 - }
 - else if(nodeType == Node.TEXT_NODE)
 - {
 - //递归出口
 - System.out.print(node.getNodeValue());
 - }
 - else if(nodeType == Node.COMMENT_NODE)
 - {
 - System.out.print("<!--");
 - Comment comment = (Comment)node;
 - //注释内容
 - String data = comment.getData();
 - System.out.print(data);
 - System.out.print("-->");
 - }
 - }
 - System.out.print("</" + tagName + ">");
 - }
 - }
 
sax:SAX的全称是Simple APIs for 
XML,也即XML简单应用程序接口。与DOM不同,SAX提供的访问模式是一种顺序模式,这是一种快速读写XML数据的方式。当使用SAX分析器对
XML文档进行分析时,会触发一系列事件,并激活相应的事件处理函数,应用程序通过这些事件处理函数实现对XML文档的访问,因而SAX接口也被称作事件
驱动接口。
- import java.io.File;
 - import javax.xml.parsers.SAXParser;
 - import javax.xml.parsers.SAXParserFactory;
 - import org.xml.sax.Attributes;
 - import org.xml.sax.SAXException;
 - import org.xml.sax.helpers.DefaultHandler;
 - public class SaxTest1
 - {
 - public static void main(String[] args) throws Exception
 - {
 - //step1: 获得SAX解析器工厂实例
 - SAXParserFactory factory = SAXParserFactory.newInstance();
 - //step2: 获得SAX解析器实例
 - SAXParser parser = factory.newSAXParser();
 - //step3: 开始进行解析
 - parser.parse(new File("student.xml"), new MyHandler());
 - }
 - }
 - class MyHandler extends DefaultHandler
 - {
 - @Override
 - public void startDocument() throws SAXException
 - {
 - System.out.println("parse began");
 - }
 - @Override
 - public void endDocument() throws SAXException
 - {
 - System.out.println("parse finished");
 - }
 - @Override
 - public void startElement(String uri, String localName, String qName,
 - Attributes attributes) throws SAXException
 - {
 - System.out.println("start element");
 - }
 - @Override
 - public void endElement(String uri, String localName, String qName)
 - throws SAXException
 - {
 - System.out.println("finish element");
 - }
 - }
 
- import java.io.File;
 - import java.util.Stack;
 - import javax.xml.parsers.SAXParser;
 - import javax.xml.parsers.SAXParserFactory;
 - import org.xml.sax.Attributes;
 - import org.xml.sax.SAXException;
 - import org.xml.sax.helpers.DefaultHandler;
 - public class SaxTest2
 - {
 - public static void main(String[] args) throws Exception
 - {
 - SAXParserFactory factory = SAXParserFactory.newInstance();
 - SAXParser parser = factory.newSAXParser();
 - parser.parse(new File("student.xml"), new MyHandler2());
 - }
 - }
 - class MyHandler2 extends DefaultHandler
 - {
 - private Stack<String> stack = new Stack<String>();
 - private String name;
 - private String gender;
 - private String age;
 - @Override
 - public void startElement(String uri, String localName, String qName,
 - Attributes attributes) throws SAXException
 - {
 - stack.push(qName);
 - for(int i = 0; i < attributes.getLength(); i++)
 - {
 - String attrName = attributes.getQName(i);
 - String attrValue = attributes.getValue(i);
 - System.out.println(attrName + "=" + attrValue);
 - }
 - }
 - @Override
 - public void characters(char[] ch, int start, int length)
 - throws SAXException
 - {
 - String tag = stack.peek();
 - if("姓名".equals(tag))
 - {
 - name = new String(ch, start,length);
 - }
 - else if("性别".equals(tag))
 - {
 - gender = new String(ch, start, length);
 - }
 - else if("年龄".equals(tag))
 - {
 - age = new String(ch, start, length);
 - }
 - }
 - @Override
 - public void endElement(String uri, String localName, String qName)
 - throws SAXException
 - {
 - stack.pop(); //表示该元素已经解析完毕,需要从栈中弹出
 - if("学生".equals(qName))
 - {
 - System.out.println("姓名:" + name);
 - System.out.println("性别:" + gender);
 - System.out.println("年龄:" + age);
 - System.out.println();
 - }
 - }
 - }
 
JDOM:
JDOM是一个开源项目,它基于树型结构,利用纯JAVA的技术对XML文档实现解析、生成、序列化以及多种操作。(http://jdom.org)
•JDOM 直接为JAVA编程服务。它利用更为强有力的JAVA语言的诸多特性(方法重载、集合概念等),把SAX和DOM的功能有效地结合起来。
•JDOM是用Java语言读、写、操作XML的新API函数。在直接、简单和高效的前提下,这些API函数被最大限度的优化。
jdom创建xml
- import java.io.FileWriter;
 - import org.jdom.Attribute;
 - import org.jdom.Comment;
 - import org.jdom.Document;
 - import org.jdom.Element;
 - import org.jdom.output.Format;
 - import org.jdom.output.XMLOutputter;
 - public class JDomTest1
 - {
 - public static void main(String[] args) throws Exception
 - {
 - Document document = new Document();
 - Element root = new Element("root");
 - document.addContent(root);
 - Comment comment = new Comment("This is my comments");
 - root.addContent(comment);
 - Element e = new Element("hello");
 - e.setAttribute("sohu", "www.sohu.com");
 - root.addContent(e);
 - Element e2 = new Element("world");
 - Attribute attr = new Attribute("test", "hehe");
 - e2.setAttribute(attr);
 - e.addContent(e2);
 - e2.addContent(new Element("aaa").setAttribute("a", "b")
 - .setAttribute("x", "y").setAttribute("gg", "hh").setText("text content"));
 - Format format = Format.getPrettyFormat();
 - format.setIndent(" ");
 - // format.setEncoding("gbk");
 - XMLOutputter out = new XMLOutputter(format);
 - out.output(document, new FileWriter("jdom.xml"));
 - }
 - }
 
JDOM解析xml
- import java.io.File;
 - import java.io.FileOutputStream;
 - import java.util.List;
 - import org.jdom.Attribute;
 - import org.jdom.Document;
 - import org.jdom.Element;
 - import org.jdom.input.SAXBuilder;
 - import org.jdom.output.Format;
 - import org.jdom.output.XMLOutputter;
 - public class JDomTest2
 - {
 - public static void main(String[] args) throws Exception
 - {
 - SAXBuilder builder = new SAXBuilder();
 - Document doc = builder.build(new File("jdom.xml"));
 - Element element = doc.getRootElement();
 - System.out.println(element.getName());
 - Element hello = element.getChild("hello");
 - System.out.println(hello.getText());
 - List list = hello.getAttributes();
 - for(int i = 0 ;i < list.size(); i++)
 - {
 - Attribute attr = (Attribute)list.get(i);
 - String attrName = attr.getName();
 - String attrValue = attr.getValue();
 - System.out.println(attrName + "=" + attrValue);
 - }
 - hello.removeChild("world");
 - XMLOutputter out = new XMLOutputter(Format.getPrettyFormat().setIndent(" "));
 - out.output(doc, new FileOutputStream("jdom2.xml"));
 - }
 - }
 
Dom4j
- import java.io.FileOutputStream;
 - import java.io.FileWriter;
 - import org.dom4j.Document;
 - import org.dom4j.DocumentHelper;
 - import org.dom4j.Element;
 - import org.dom4j.io.OutputFormat;
 - import org.dom4j.io.XMLWriter;
 - public class Test1
 - {
 - public static void main(String[] args) throws Exception
 - {
 - // 创建文档并设置文档的根元素节点 :第一种方式
 - // Document document = DocumentHelper.createDocument();
 - //
 - // Element root = DocumentHelper.createElement("student");
 - //
 - // document.setRootElement(root);
 - // 创建文档并设置文档的根元素节点 :第二种方式
 - Element root = DocumentHelper.createElement("student");
 - Document document = DocumentHelper.createDocument(root);
 - root.addAttribute("name", "zhangsan");
 - Element helloElement = root.addElement("hello");
 - Element worldElement = root.addElement("world");
 - helloElement.setText("hello");
 - worldElement.setText("world");
 - helloElement.addAttribute("age", "20");
 - XMLWriter xmlWriter = new XMLWriter();
 - xmlWriter.write(document);
 - OutputFormat format = new OutputFormat(" ", true);
 - XMLWriter xmlWriter2 = new XMLWriter(new FileOutputStream("student2.xml"), format);
 - xmlWriter2.write(document);
 - XMLWriter xmlWriter3 = new XMLWriter(new FileWriter("student3.xml"), format);
 - xmlWriter3.write(document);
 - xmlWriter3.close();
 - }
 - }
 
- import java.io.File;
 - import java.util.Iterator;
 - import java.util.List;
 - import javax.xml.parsers.DocumentBuilder;
 - import javax.xml.parsers.DocumentBuilderFactory;
 - import org.dom4j.Document;
 - import org.dom4j.Element;
 - import org.dom4j.io.DOMReader;
 - import org.dom4j.io.SAXReader;
 - public class Test2
 - {
 - public static void main(String[] args) throws Exception
 - {
 - SAXReader saxReader = new SAXReader();
 - Document doc = saxReader.read(new File("student2.xml"));
 - Element root = doc.getRootElement();
 - System.out.println("root element: " + root.getName());
 - List childList = root.elements();
 - System.out.println(childList.size());
 - List childList2 = root.elements("hello");
 - System.out.println(childList2.size());
 - Element first = root.element("hello");
 - System.out.println(first.attributeValue("age"));
 - for(Iterator iter = root.elementIterator(); iter.hasNext();)
 - {
 - Element e = (Element)iter.next();
 - System.out.println(e.attributeValue("age"));
 - }
 - System.out.println("---------------------------");
 - DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
 - DocumentBuilder db = dbf.newDocumentBuilder();
 - org.w3c.dom.Document document = db.parse(new File("student2.xml"));
 - DOMReader domReader = new DOMReader();
 - //将JAXP的Document转换为dom4j的Document
 - Document d = domReader.read(document);
 - Element rootElement = d.getRootElement();
 - System.out.println(rootElement.getName());
 - }
 - }
 
- import java.io.FileWriter;
 - import org.jdom.Attribute;
 - import org.jdom.Document;
 - import org.jdom.Element;
 - import org.jdom.output.Format;
 - import org.jdom.output.XMLOutputter;
 - public class Test3
 - {
 - public static void main(String[] args) throws Exception
 - {
 - Document document = new Document();
 - Element root = new Element("联系人列表").setAttribute(new Attribute("公司",
 - "A集团"));
 - document.addContent(root);
 - Element contactPerson = new Element("联系人");
 - root.addContent(contactPerson);
 - contactPerson
 - .addContent(new Element("姓名").setText("张三"))
 - .addContent(new Element("公司").setText("A公司"))
 - .addContent(new Element("电话").setText("021-55556666"))
 - .addContent(
 - new Element("地址")
 - .addContent(new Element("街道").setText("5街"))
 - .addContent(new Element("城市").setText("上海"))
 - .addContent(new Element("省份").setText("上海市")));
 - XMLOutputter output = new XMLOutputter(Format.getPrettyFormat()
 - .setIndent(" ").setEncoding("gbk"));
 - output.output(document, new FileWriter("contact.xml"));
 - }
 - }
 
                    
                
                
            
        
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