Analytic method of document tree

The XML text used in this summary

1, <?xml version= "1.0" encoding= "UTF-8" standalone= "no"?>
<!--introduction of a DTD file tagged--><!--<! DOCTYPE Bookshelf SYSTEM "BOOK.DTD" >-
< bookshelf >
< book isbn= "a" press = "Publishing House" >
< title > Kingdoms </title >
< author > Luo guanzhong </author >
< wholesale price >500￥</wholesale price >
< price >100$</price >
</book >
< book isbn= "B" press = "Publishing House" >
< title > Journey to </title >
< author > Wu Chengen </author >
< price >55￥</price >
</book >
</Bookshelf >
Second, using JAXP to carry on the DOM analytic method
1, first to obtain the Analytical factorydocumentbuilderfactory
Javax.xml.parsers class

**documentbuilderfactory: Defines a factory API that enables applications to get parsers that generate DOM objects from an XML document.

Documentbuilderfactory factory = documentbuilderfactory.newinstance ();

**newinstance () Method: Gets the new real class of the documentbuilderfactory. This static method creates a new factory real class.
2. Get the parserDocumentbuilder
Class Documentbuilder
* * Define the API to make it from the XML document to the DOM document Real class. Application programmers can get a document from XML

Documentbuilder builder = Factory.Newdocumentbuilder ();

**newdocumentbuilder: Creates a new Documentbuilder real class with the parameters of the current configuration.

3. Parse the developed XML document. Get the Document object for the DOM tree that represents memory

DocumentDocument = Builder.Parse ("Src/book.xml");
**builder.parse () method: Resolves the contents of a given input source to an XML document. and returns a new DOM document object

Third, get the content of a specific node: columns such as: Print the author of the second book
1, according to the contents of the label to obtain all the author's name
NodeList nodelist=document.getElementsByTagName ()
NodeList: interface provides an abstraction of an ordered set of nodes
2. Get the second author element by index
Node node=nodelist.Item (1);
3. Print the text of the element
String Text=node.gettextcontent ();
System.out.println (text);
Iv. traversing all ELEMENT nodes: the node name of the printed element
1. Determine if the current node is a node of an element
Short Nd=node.getnodetype ();
if (Nd==node.element_node) {
If it is: print the name of the element node
System.out.println (Node.getnodename ());
}
If not to find their child node
NodeList nodelist=node.getchildnodes ();
int length=nodelist.getlength ();//Gets the length of the Child's node
for (int 1=0;i<length;i++) {
Traverse child nodes for recursion
Node N=nodelist.item (i);
Test2 (n);
}
V. Modifying the topic content of ELEMENT nodes
1, column: Find the price of the first book
NodeList NodeList = docuement.getelementsbytagname ("price");
2. Set the content of the theme
Node No=nodelist.item (0);//Get his nodes
No.settextcontent ("100$");//Set his subject content
3.write the document tree in memory back into the XML
Transformerfactory factory = Transformertactory.newinstance ();
Transformer tr = Factory.newtransformer ();
Tr.transformer (New Domsource (doument), New Streamresult ("Src/book.xml"));
Vi. adding child element nodes to the specified element node
1. Create a new element and set its contents
Element element = element.createelement ("Internal price");
Set his text content
Element.settexstcontent ("300$");
2. Find the first book
NodeList NodeList = document.getElementsByTagName ("book");
Node first =nodelist.item (0);
3. Attach the new node to the first book
First.appendchild (Element)
4. Write the document tree in memory into XML
Transformerfactory factory = Transformerfactory.newinstace ();
Transformer Tr=factory.newtransformer ();
Tr.transformer (new Domsource (document), New Streamresult ("Src/book.xml"));
Add a sibling element node to the specified element node: Columns such as: Add a wholesale price before the price of the first book
1. Create and set up the theme content
Element element = documcnet.createelement ("wholesale price");
Element.settextcontent ("500$");
2. Find the price of the first book
NodeList NodeList = document.getElementsByTagName ("price");
Node node=nodelist.item (0);
3. Add the newly created element in front of the selling price:
To add a child node, be sure to use the parent element to
Node.getparentnode (). insertbefore (Element,node);
4. Write the document tree in memory back into XML
Transformerfactory factory = Transformerfactory.newinstance ();
Transformer tr = Factory.newtransformer ()
Tr.transformer (new Domsource (document), New Streamresult ("Src/book.xml"));
Viii. Delete the node of the specified element
1. Deleting child nodes requires parent node to delete
Columns such as: Find internal price to delete
NodeList NodeList = document.getElementsByTagName ("Internal price");
Node node = nodelist.item (0);
Node.getpraentnode (). Removechhild (n);
2. Write the memory's document tree back into the XML
Transformerfactory factory=transformerfactory.newinstance ();
Transformer tr=factory. Transformer ();
Tr.transformer (new Domsource (document), New Streamresult ("Src/book.xml"));
Ix. manipulating XML element properties: Printing the first book's Publishing house
1, first to get the first
Node node = document.getelementsbytagname ("book"). Item (0);
2. Print the value of the specified property
Element e = (element) n;
System.out.println (E.getattribute ("Publishing house"));

Analytic method of document tree