Talk about the technical principles of SpringSource Javax XML Stream framework in the Java class library
SpringSource Javax XML Stream framework is a set of technical principles for processing XML data in the Java library.This article will discuss the working principle of the framework in detail and provide some Java code examples to illustrate.
A common requirement of using XML data in the Java library is analysis and generating XML documents.SpringSource Javax XML Stream framework provides a set of APIs for parsing and generating XML streams.It is based on the XML PULL parser, which is a lightweight and efficient parser.
First, let's take a look at how to use SpringSource Javax XML Stream framework to resolve XML data.To analyze XML, a XMLSTREAMREADER object needs to be created.You can obtain the XMLSTREAMREADER object through the newInstance method of XMLINPUTFACTORY.Next, you can use the XMLSTREAMREADER object to iterate the different parts of XML, such as elements, attributes, texts, etc.The following is a simple example:
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamReader;
import java.io.FileInputStream;
import java.io.InputStream;
public class XMLParserExample {
public static void main(String[] args) throws Exception {
// Create XMLINPUTFACTORY object
XMLInputFactory factory = XMLInputFactory.newInstance();
// Create xmlstreamReader objects
InputStream inputStream = new FileInputStream("example.xml");
XMLStreamReader reader = factory.createXMLStreamReader(inputStream);
// Start parsing XML
while (reader.hasNext()) {
int eventType = reader.next();
// Treatment of different types of XML nodes
switch (eventType) {
case XMLStreamReader.START_ELEMENT:
System.out.println ("Starting Element:" + Reader.getLocalName ());
break;
case XMLStreamReader.END_ELEMENT:
System.out.println ("Ending Element:" + Reader.getLocalName ());
break;
case XMLStreamReader.CHARACTERS:
System.out.println ("Text:" + Reader.gettext ());
break;
}
}
// Close the resource
reader.close();
}
}
In the above code, we created a XMLSTREAMREADER object and handled different nodes in XML through circulation.By calling the XMLSTREAMREADER object, we can obtain the type of node (such as starting elements, ending elements or text) and nodes.
In addition to analyzing XML, Springsource Javax XML Stream framework also provides API to generate XML documents.In order to generate XML, you need to use XMLOUTPUTFACTORY's Newinstance method to obtain XMLOUTPUTFACTORY objects.Then, the method of this object can be used to create the XMLSTREAMWRITER object so that the content can be written into the XML document.The following is a simple example:
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamWriter;
import java.io.FileOutputStream;
import java.io.OutputStream;
public class XMLGeneratorExample {
public static void main(String[] args) throws Exception {
// Create XMLOUTPUTFACTORY object
XMLOutputFactory factory = XMLOutputFactory.newInstance();
// Create xmlstreamWriter objects
OutputStream outputStream = new FileOutputStream("example.xml");
XMLStreamWriter writer = factory.createXMLStreamWriter(outputStream);
// Start generate XML
writer.writeStartDocument();
writer.writeStartElement("book");
writer.writeStartElement("title");
writer.writeCharacters("Java Programming");
writer.writeEndElement();
writer.writeStartElement("author");
writer.writeCharacters("John Smith");
writer.writeEndElement();
writer.writeEndElement();
writer.writeEndDocument();
// Close the resource
writer.close();
}
}
In the above code, we created a XMLSTREAMWRITER object and used the method of this object to build different parts of the XML document.By calling WriteStartelement, WriteCharacters, and WriteEndelement, we can specify the starting marks, content and end marks of the element.Finally, we call the WritendDocument method to complete the generating XML document.
In summary, Springsource Javax XML Stream framework provides APIs for parsing and generating XML in the Java class library.It is based on XML PULL parser and can efficiently process XML data.By using the method of XMLSTREAMREADER and XMLSTREAMWRITER, we can easily analyze and generate XML documents.
