dom4j downloading and using dom4j Read and write XML introduction

To read and write XML documents using DOM4J, you need to download the DOM4J package first, dom4j the official website in http://www.dom4j.org/
Currently the latest dom4j package download address: Http://nchc.dl.sourceforge.net/sourceforge/dom4j/dom4j-1.6.1.zip

After unlocking there are two packages, just manipulate the XML document to add Dom4j-1.6.1.jar to the project, if you need to use XPath, you also need to add the package Jaxen-1.1-beta-7.jar.

The following are the relevant actions:

I. Document Object-related

1. Read the XML file and get the Document object.
Saxreader reader = new Saxreader ();
Document document = Reader.read (new File ("Input.xml"));

2. Parse the text in XML form to get the Document object.
String Text = "<members></members>";
Document document = Documenthelper.parsetext (text);
3. Proactively create document objects.
Document document = Documenthelper.createdocument ();
Element root = Document.addelement ("members");//Create root node
Two. Node-related

1. Gets the root node of the document.
Element Rootelm = Document.getrootelement ();
2. Obtain a single child node of a node.
Element memberelm=root.element ("member");//"member" is a node name
3. Get the text of the node
String Text=memberelm.gettext ();
You can also use:
String text=root.elementtext ("name"), which is the text that gets the name byte point under the root node.

4. Obtain all the byte points named "member" under a node and traverse them.
List nodes = rootelm.elements ("member");

for (Iterator it = Nodes.iterator (); It.hasnext ();) {
Element elm = (Element) It.next ();
Do something
}
5. Traverse all child nodes under a node.
For (Iterator it=root.elementiterator (); It.hasnext ();) {
element element = (Element) It.next ();
Do something
}
6. Add a child node under a node.
Element Ageelm = newmemberelm.addelement ("Age");
7. Set the node text.
Ageelm.settext ("29");
8. Delete a node.
Parentelm.remove (Childelm);//Childelm is the node to be deleted, Parentelm is its parent node
Three. Attribute-related.
1. Get a property under a node
Element root=document.getrootelement ();
Attribute attribute=root.attribute ("size");//Property name Name
2. Get the text of the attribute
String Text=attribute.gettext ();
You can also use:
String text2=root.element ("name"). AttributeValue ("FirstName"); This is the value of the property firstname that gets the name byte point under the root node.

3. Traverse all properties of a node
Element root=document.getrootelement ();
For (Iterator it=root.attributeiterator (); It.hasnext ();) {
Attribute Attribute = (Attribute) it.next ();
String Text=attribute.gettext ();
System.out.println (text);
}
4. Set the properties and text of a node.
Newmemberelm.addattribute ("name", "sitinspring");
5. Set the text of a property
Attribute Attribute=root.attribute ("name");
Attribute.settext ("sitinspring");
6. Delete a property
Attribute attribute=root.attribute ("size");//Property name Name
Root.remove (attribute);
Four. Write the document to an XML file.
1. The document is all in English, does not set the encoding, the direct writing form.
XMLWriter writer = new XMLWriter (New FileWriter ("Output.xml"));
Writer.write (document);
Writer.close ();
2. The document contains Chinese, formatting the format of the written form of the encoding.
OutputFormat format = Outputformat.createprettyprint ();
Format.setencoding ("GBK"); Specify XML encoding
XMLWriter writer = new XMLWriter (New FileWriter ("Output.xml"), format);

Writer.write (document);
Writer.close ();
Five. Conversion of strings to XML
1. Converting a string to XML
String Text = "<members> <member>sitinspring</member> </members>";
Document document = Documenthelper.parsetext (text);
2. Convert the XML of a document or node to a string.
Saxreader reader = new Saxreader ();
Document document = Reader.read (new File ("Input.xml"));
Element root=document.getrootelement ();
String Docxmltext=document.asxml ();
String Rootxmltext=root.asxml ();
Element memberelm=root.element ("member");
String Memberxmltext=memberelm.asxml ();
Six. Use XPath to quickly locate the node.
Example of a read XML document
<?xml version= "1.0" encoding= "UTF-8"?>
<projectDescription>
<name>MemberManagement</name>
<comment></comment>
<projects>
<project>PRJ1</project>
<project>PRJ2</project>
<project>PRJ3</project>
<project>PRJ4</project>
</projects>
<buildSpec>
<buildCommand>
<name>org.eclipse.jdt.core.javabuilder</name>
<arguments>
</arguments>
</buildCommand>
</buildSpec>
<natures>
<nature>org.eclipse.jdt.core.javanature</nature>
</natures>
</projectDescription>

Use XPath to quickly find node project.
public static void Main (string[] args) {
Saxreader reader = new Saxreader ();

try{
Document doc = Reader.read (new File ("Sample.xml"));

List projects=doc.selectnodes ("/projectdescription/projects/project");

Iterator It=projects.iterator ();

while (It.hasnext ()) {
Element elm= (Element) It.next ();
System.out.println (Elm.gettext ());
}

}
catch (Exception ex) {
Ex.printstacktrace ();
}
}