XML series: (6) XML parsing-dom4j Dom parsing method reading XML

Dom4j tool, is unofficial, not in the JDK.

Steps to use:

1) Import the core package of dom4j. Dom4j-1.6.1.jar

2) write the code dom4j read the XML file

Animals.xml

<?xml version= "1.0" encoding= "UTF-8"? ><animals><cat id= "c001" name= "Meow Mew" ><Home> Mars 

1. Read XML

1.1. Get the Document Object
Package Com.rk.xml.f_dom4j_read;import Java.io.file;import Org.dom4j.document;import org.dom4j.DocumentException; Import org.dom4j.io.saxreader;/** * First DOM4J Read XML document example * Get Document Object * @author RK */public class Demo01{public static Voi D main (string[] args) {try{//1. Create an XML parser object Saxreader reader = new Saxreader ();//2. Read XML document, return Document Object doc = Reader.read (New File ("./src/animals.xml")); System.out.println (DOC);} catch (Documentexception e) {e.printstacktrace (); throw new RuntimeException (e);}}

1.2. read XML file contents: node, tag, attribute, text
package com.rk.xml.f_dom4j_read;import java.util.list;import java.io.file;import  java.util.iterator;import org.dom4j.document;import org.dom4j.documentexception;import  org.dom4j.element;import org.dom4j.node;import org.dom4j.attribute;import  org.dom4j.io.saxreader;import org.junit.test;/** *  second dom4j reads XML file contents  *  nodes  *   Tags  *  properties  *  text  *  @author  rk * */public class demo02 {/** *  Get the node  * 1, get the root element document.getrootelement ()  * 2 through the document file, get all the child nodes under the tag element  branch.nodeiterator ()  * 3, the name of the acquired node, type: Node.getname (),  node.getnodetype (),  Node.getnodetypename ()  */@Testpublic  void testnode () {try{//1. read XML document, return Document Object Saxreader  reader = new saxreader ();D Ocument doc = reader.read (New File ("./src/ Products.xml "));//2, get root tag element rootelement = doc.getrooteLement ();//3, traverse all nodes of the document Getchildnodes (rootelement);} catch  (documentexception e) {e.printstacktrace ();}} Private void getchildnodes (Element elem) {//nodeiterator:  gets all child node objects under the current node (nodes that do not contain grandchildren) @ Suppresswarnings ("Unchecked") iterator<node> it = elem.nodeiterator (); while (It.hasNext ()) { Node node = it.next (); System.out.println (Node.getname ()  +  "= = ="  + node.getnodetype ()  +  "= = ="  +  node.getnodetypename ());//determine if the Label element if (node instanceof element) {getchildnodes (Element) node);}} /** *  get the label  * 1, get a specific label  element.element (string name)  :  Get the first sub-label of the specified name under the current tab &NBSP;*&NBSP;2, get all sub-tags  element.elementiterator (string name):   Gets all the child tags of the specified name under the current label  */@Testpublic  void testelement ()  throws exception{//1. Read the XML document, Returns the Document object Saxreader reader = new saxreader ();D Ocument doc = reader.read ( New fIle ("./src/animals.xml"));//2. Get root Tag System.out.println ("===================================2"); Element rootelement = doc.getrootelement ();//Get node-related information string name =  Rootelement.getname ();//Get Node name Short type = rootelement.getnodetype ();//Get node type string  Typename = rootelement.getnodetypename ();//Gets the node type name System.out.println (name +  "\ T"  +  type +  "\ T"  + typename)//3. Gets the first sub-label of the specified name under the current label System.out.println ("================== =================3 "); Element productelement = rootelement.element ("Dog"); System.out.println (Productelement.getname ())//4. Gets all the child tags of the specified name under the current label System.out.println ("======================== ===========4 "), @SuppressWarnings (" unchecked ") iterator<element> it =   Rootelement.elementiterator ("Cat"), while (It.hasnext ()) {element elem = it.next (); System.out.println (Elem.getname ());} 5. Get all the sub-tags under the current tab SYSTEM.OUT.PRINTLN ("===================================5 "), @SuppressWarnings (" Unchecked ") list<element> list = rootelement.elements (); /Traversal list Method//1) traditional for loop   2) enhanced for loop  3) iterator//for (Int i=0;i<list.size (); i++)//{// System.out.println (List.get (i). GetName ());//}//for (element elem : list)//{//system.out.println ( Elem.getname ());//}iterator<element> iterator = list.iterator (); while (Iterator.hasNext ()) {Element elem = iterator.next (); System.out.println (Elem.getname ());} 6, to obtain a deeper level of the label (method can only be a layer of access) System.out.println ("===================================6"); Element nameelement = rootelement.element ("Dog"). Element ("Home"); System.out.println (Nameelement.getname ()); System.out.println (Nameelement.gettext ()); System.out.println (Nameelement.getpath ()); System.out.println (Nameelement.getuniquepath ());} /** *  gets the property  * 1, gets a specific property  * 2, gets all the attributes under the tag element  */@Testpublic  void  Testattribute ()  throws exception{//reads an XML document, returns the File Object Saxreader reader = new saxreader ();D ocument doc =  Reader.read (New file ("./src/animals.xml")); Element rootelement = doc.getrootelement ();//Gets the property: (The Label object where the property is first obtained, and then the property can be obtained)//1. Get the Tag object element  dogelement = rootelement.element ("Dog");//2. Gets the attribute//2.1   gets the property value of the specified name System.out.println ( "===================================2.1"); String idvalue = dogelement.attributevalue ("id"); System.out.println (idvalue);//2.2  Gets the Property object with the specified property name System.out.println ("===================================2.2 "); Attribute idattr = dogelement.attribute ("name");//getname:  property name      GetValue: Attribute value System.out.println (idattr.getname ()  +  "="  + idattr.getvalue ());//2.3  Get all Property objects, return the list collection System.out.println ("===================================2.3"); @SuppressWarnings ("Unchecked") List<attribute> list = dogelement.attributes ();//Traverse property for (Attribute&nbsP;attr : list) {System.out.println (Attr.getname ()  +  "="  + attr.getvalue ());} 2.4  gets all the property objects, returns the iterator System.out.println ("===================================2.4"); @SuppressWarnings (" Unchecked ") iterator<attribute> iterator = rootelement.element (" Cat "). AttributeIterator (); while (Iterator.hasnext ()) {attribute attr = iterator.next (); System.out.println (Attr.getname ()  +  "="  + attr.getvalue ());}} /** *  Gets the text  * 1, gets the text of the current LABEL element Element.gettext ()  * 2, gets the text of the child label Element Element.elementtext ( String name)  */@Testpublic  void testtext ()  throws exception{//read the XML document, Returns the Document object Saxreader reader = new saxreader ();D Ocument doc = reader.read ( New file ("./src/animals.xml")); Element rootelement = doc.getrootelement ();//note:  spaces and line breaks are also XML content string content =  rootelement.gettext (); System.out.println ("==start=="  + content +  "==end==");//Get the text (get the label first, then get the text on the label) element borndateelement =  Rootelement.element ("Cat"). Element ("Borndate");//1.  get text string text =  Borndateelement.gettext (); The text of System.out.println (Borndateelement.getname ()  +  "element is"  + text);//2.  Gets the text content of the specified sub-label name String text2 = rootelement.element ("Dog"). Elementtext ("Home"); System.out.println (Text2);}}


1.3. Practice-Read the contents of the XML document in full
package com.rk.xml.f_dom4j_read;import java.io.file;import java.util.iterator;import  org.dom4j.document;import org.dom4j.node;import org.dom4j.element;import org.dom4j.attribute; import org.dom4j.io.saxreader;/** *  exercise-Full Read XML document content  *  @author  rk * */ Public class demo03{public static void main (String[] args)  throws  exception{//read XML document Saxreader reader = new saxreader ();D ocument doc =  Reader.read (New file ("./src/animals.xml"));//Read root tag element rootelement = doc.getrootelement (); Stringbuilder sb = new stringbuilder (); Getchildnodes (ROOTELEMENT,SB); System.out.println (Sb.tostring ());} /** *  gets all child nodes of the current label  */private static void getchildnodes (element  CURRENTELEMENT,&NBSP;STRINGBUILDER&NBSP;SB) {string name = currentelement.getname ();// Start label Startsb.append ("<" +name);//Get the list of attributes for the label @suppresswarnings ("Unchecked") iterator<attribute> iterator =  Currentelement.attributeiterator (); while (Iterator.hasnext ()) {attribute attr = iterator.next (); String attrname = attr.getname (); String attrvalue = attr.getvalue (); Sb.append (" "  + attrName +  "=\" "  + attrValue +  "\" ");} Start tag endsb.append (">");//Get child node @suppresswarnings ("Unchecked") iterator<node> it =  Currentelement.nodeiterator (); while (It.hasnext ()) {node node = it.next (); short type =  node.getnodetype (); if (Type == node.element_node) {getchildnodes (ELEMENT) NODE,&NBSP;SB);} Else if (Type == node.text_node) {sb.append (Node.gettext ());} else{//other cases, do not do the processing}}//end tag sb.append ("</"  + name +  ">");}}



2. Mind Mapping
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XML series: (6) XML parsing-dom4j Dom parsing method reading XML