[Backup] XML parsing tool in java-Introduction to dom4j

To use dom4j to read and write XML documents, you need to first download the dom4j package, dom4j official website in http://www.dom4j.org/

Currently the latest dom4j package: http://nchc.dl.sourceforge.net/sourceforge/dom4j/dom4j-1.6.1.zip

There are two packages after the UNDO, only the XML document to operate the dom4j-1.6.1.jar to add the project can be, if you need to use XPath also need to add the package jaxen-1.1-beta-7.jar.

Perform the following operations:

1. Document Object-related

1. Read the XML file and obtain the document object.
Saxreader reader = new saxreader ();
Document document = reader. Read (new file ("input. xml "));

2. parse the text in XML format to obtain the document object.
String text = "<members> </members> ";
Document document = incluenthelper. parseText (text );
3. Create a document Object.
Document document = incluenthelper. createDocument ();
Element root = document. addElement ("members"); // create a root node

Ii. node Problems

1. Get the root node of the document.
Element rootElm = document. getRootElement ();
2. Obtain a single subnode of a node.
Element memberElm = root. element ("member"); // "member" is the node name.
3. Get the node text
String text = memberElm. getText ();
You can also use:
String text = root. elementText ("name"); this is the text that retrieves the name byte under the root node.

4. retrieve all the byte points under a node named "member" 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 subnodes under a node.
For (iterator it = root. elementiterator (); it. hasnext ();){
Element element = (element) it. Next ();
// Do something
}
6. Add a subnode 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, and parentelm is the parent node.

Iii. property-related

1. Obtain an attribute under a node
Element root = document. getRootElement ();
Attribute attribute = root. Attribute ("size"); // attribute name
2. Get the attribute text
String text = attribute. getText ();
You can also use:
String text2 = root. element ("name"). attributeValue ("firstname"); this is the value of the firstname attribute of the name byte point under the root node.

3. traverse all attributes of a node
Element root = document. getRootElement ();
For (Iterator it = root. attributeIterator (); it. hasNext ();){
Attribute attribute Attribute = (Attribute) it. next ();
String text = attribute. getText ();
System. out. println (text );
}
4. Set attributes and text of a node.
NewMemberElm. addattrielm ("name", "sitinspring ");
5. Set the attribute text
Attribute attribute = root. Attribute ("name ");
Attribute. setText ("sitinspring ");
6. delete an attribute
Attribute attribute = root. Attribute ("size"); // attribute name
Root. remove (attribute );

4. Write documents into XML files

1. The document is in full English and is written directly without encoding.
XMLWriter writer = new XMLWriter (new FileWriter ("output. xml "));
Writer. write (document );
Writer. close ();
2. The document contains Chinese characters and sets the encoding format for writing.
OutputFormat format = OutputFormat. createPrettyPrint ();
Format. setEncoding ("GBK"); // specify the XML Encoding
XMLWriter writer = new XMLWriter (new FileWriter ("output. xml"), format );

Writer. Write (document );
Writer. Close ();

5. Conversion of strings and XML

1. convert a string to XML
String text = "<members> <member> sitinspring </member> </members> ";
Document document = incluenthelper. parsetext (text );
2. Convert the XML of the document or node into 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 ();

6. Use XPath to quickly find a node

Example of an XML document read
<? 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 the 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 ();
}
}