java解析xml的几种方式
第一种:DOM。
DOM的全称是DocumentObjectModel,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")); } }