Three ways to parse XML in Java

Three ways to parse XML in Java

1.SAX Event Parsing

Package Com.wzh.sax;import Org.xml.sax.attributes;import Org.xml.sax.saxexception;import Org.xml.sax.helpers.defaulthandler;//public class Saxhandler extends DefaultHandler {@Overridepublic void Startdocument () throws Saxexception {System.out.println ("Start parsing XML Document ...");} @Overridepublic void Enddocument () throws Saxexception {System.out.println ("End parsing XML Document ...");} @Overridepublic void Startelement (String uri, String localname, String Qname,attributes Attributes) throws Saxexception { TODO auto-generated Method Stubsuper.startelement (URI, LocalName, qName, attributes); System.out.println ("Start parsing node [" +qname+ "] ..."); SYSTEM.OUT.PRINTLN ("Common [" +attributes.getlength () + "] Properties");} @Overridepublic void characters (char[] ch, int start, int length) throws Saxexception {//TODO auto-generated method Stubsu Per.characters (CH, start, length); String content =new string (ch,start,length); SYSTEM.OUT.PRINTLN (content);} @Overridepublic void EndElement (String uri, String localname, String qName) throws Saxexception {//TODO auto-generated Method Stubsuper.endelement (URI, LocalName, QName); SYSTEM.OUT.PRINTLN ("End Parsing XML node ...");}}

　　

2.Dom Load parsing

Package Com.wzh.dom;import Java.util.iterator;import Javax.xml.parsers.documentbuilder;import Javax.xml.parsers.documentbuilderfactory;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;public class DomHandler {/* * Parse XML */ public void Read (String fileName) throws Exception {//Define factory API enables applications to obtain a parser that generates a DOM object tree from an XML document Documentbuilderfactory Factory = Documentbuilderfactory.newinstance ();//After obtaining an instance of this class, you will be able to parse Xmldocumentbuilder builder from various input sources = Factory.newdocumentbuilder ();//Builder.parse (This.getclass (). getResourceAsStream ("/" + fileName);// The document interface represents the entire HTML or XML documentation, conceptually, it is the root of the document tree and provides a basic access to the document data File = Builder.parse (This.getclass (). getResourceAsStream ("/" + fileName);//Get root node element root = Document.getdocumentelement (); System.out.println (Root.getnodename ());//Read the database node NodeList interface provides an abstraction of the ordered set of nodes nodeList nodeList = Root.getelementsbytagname ("database"); for (int i = 0; i < nodelist.getlength (); i++) {//Get a node nodes = Nodelist.item (i);//Get all the properties of the node NamedNodeMap attributes = Node.getattributes (); for (int j = 0; J &lt ; Attributes.getlength (); J + +) {Node attribute = Attributes.item (j); System.out.println (Attribute.getnodename () + ":" + attribute.getnodevalue ()); Get all child node Data nodelist childnodes=node.getchildnodes (); for (int j = 0; J < Childnodes.getlength (), j + +) {node childnode=c Hildnodes.item (j); System.out.println (Childnode.getnodename () + ":" +childnode.getnodevalue ());}}} public static void Main (string[] args) throws Exception {new Domhandler (). Read ("Data-source.xml");}}

　　

3.DOM4J parsing

Package com.wzh.dom4j;

Import Java.io.FileOutputStream;
Import Java.sql.DatabaseMetaData;
Import Java.util.Iterator;
Import java.util.List;

Import org.dom4j.*;
Import Org.dom4j.io.OutputFormat;
Import Org.dom4j.io.SAXReader;
Import Org.dom4j.io.XMLWriter;

public class Dom4jhandler {

public void Add () throws Exception {
//1. Create a document
Document document = Documenthelper.createdocument ();
2. Add data to document
Element root = Document.addelement ("DataSource");
Add a comment
Root.addcomment ("This is a comment message");
Add a child node under the root root node
Element database = root.addelement ("database");
Database.addattribute ("name", "MySQL");
Database.addattribute ("version", "5.0");
//Add child nodes
Database.addelement ("Driver"). SetText ("Com.mysql.jdbc.Driver");
Database.addelement ("url")
. SetText ("Jdbc:mysql://localhost:3306/myjdbc");
Database.addelement ("User"). SetText ("root");
Database.addelement ("password"). SetText ("root");
//3. Write document out of file
OutputFormat format = Outputformat.createprettyprint ();
Format.setencoding ("Utf-8");
///FileOutputStream the path generated by default at the root path
XMLWriter XW = new XMLWriter (New FileOutputStream ("Db.xml"), format);
Xw.write (document);
Xw.close ();
}

public void Update (String fileName) throws Exception {
SAX parser
Saxreader Saxreader = new Saxreader ();
Read the Object
Document document = Saxreader.read (This.getclass (). getResourceAsStream (
"/" + fileName);
Element root = Document.getrootelement ();
list<element> Databases_node = root.elements ("database");
for (Element Database_node:databases_node) {
if (Database_node.attributevalue ("name"). Equalsignorecase ("MySQL")) {
System.out.println ("Old:"
+ database_node.attributevalue ("name"));
Database_node.attribute ("name"). SetText ("Oracle");
System.out.println ("Update:"
+ database_node.attributevalue ("name"));

Database_node.element ("Driver"). SetText ("Oracel");
Database_node.element ("url"). SetText ("jdbc");

Delete Password node
Database_node.remove (database_node.element ("password"));

Delete Property
Database_node.remove (Database_node.attribute ("version"));
}
}

OutputFormat format = Outputformat.createprettyprint ();
Format.setencoding ("Utf-8");
FileOutputStream the default generated path in the root path
XMLWriter XW = new XMLWriter (New FileOutputStream ("Db2.xml"), format);
Xw.write (document);
Xw.close ();
}

public void Read (String fileName) throws Exception {
SAX parser
Saxreader Saxreader = new Saxreader ();
Read the Object
Document document = Saxreader.read (This.getclass (). getResourceAsStream (
"/" + fileName);
Element root = Document.getrootelement ();
SYSTEM.OUT.PRINTLN ("root node:" + Root.getname ());

//List<element> childelements=root.elements ();
List<element> childelements = root.elements ("database");
for (Element child:childelements) {
//Get property does not know property name when traversing method
List<attribute> attributes = Child.attributes ();
//For (Attribute attribute:attributes) {
//System.out.println (Attribute.getname () + ":" +attribute.getvalue () );
//}
String name = Child.attributevalue ("name");
//String Version = Child.attributevalue ("version");
String Version = Child.attribute ("version"). GetValue ();
System.out.println (name + ":" + version);

Get child nodes
List<element> childs=child.elements ();
for (Element element:childs) {
System.out.println (Element.getname () + ":" +element.gettext ());
// }
System.out.println (Child.elementtext ("Driver"));
System.out.println (child.element ("url"). GetText ());
System.out.println (Child.elementtexttrim ("user"));
System.out.println (child.element ("password"). Gettexttrim ());

}
}

public static void Main (string[] args) throws Exception {
New Dom4jhandler (). Read ("Data-source.xml");
New Dom4jhandler (). Add ();
New Dom4jhandler (). Update ("Data-source.xml");
}
}

Three ways to parse XML in Java