Java API For XML Processing framework: Introduction to the Technical Principles of Java API Processing Framework)

Java API for XML Processing (referred to as JAXP) is the Java framework for processing XML.It provides a set of APIs for analysis, generation, conversion, and verification of XML documents.JAXP is part of the Javaee platform that can be used in Java applications and Java Applet. JAXP's technical principles mainly involve three aspects: parser (Parser), document object models (DOM) and Transformer. The parser is one of the core components used by JAXP to analyze XML documents.It converts the XML document into an internal representation form that can be read and operated by the program.JAXP supports two parsers: DOM parser and SAX parser.The DOM parser loads the entire XML document to the memory. It is represented by a tree structure, allowing the application to easily traverse and modify the document.The SAX parser uses an event -driven method to analyze the XML document, read the XML node one by one, and trigger the corresponding event callback method. It is suitable for large XML documents and performance -sensitive environments. Document object model (DOM) is a standard interface used by JAXP to represent XML documents.It provides a layered, object -based method to operate XML documents.DOM represents the entire XML document as a node tree, and each node is an object with attributes and methods.Developers can traverse, query and modify the content of XML documents by operating the DOM. The converter is a component for JAXP to convert XML documents.It can convert one XML document into another XML document, HTML document, text document or binary document.JAXP provides an XSLT converter to convert the XML document through the XSLT style table.Developers can use XSLT to convert the structure, content and style of the XML document to generate formats that meet their needs. Here are some examples of Java code using JAXP: 1. Use the DOM parser to parse the XML document: // Import jaxp -related classes import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.DocumentBuilder; import org.w3c.dom.Document; import org.w3c.dom.NodeList; import org.w3c.dom.Node; // Create a DocumentBuilderFactory object DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); // Create the DocumentBuilder object DocumentBuilder builder = factory.newDocumentBuilder(); // Use documentbuilder to parse XML documents Document document = builder.parse(new File("input.xml")); // Get the root node Node root = document.getDocumentElement(); // Traversing sub -nodes NodeList nodeList = root.getChildNodes(); for (int i = 0; i < nodeList.getLength(); i++) { Node node = nodeList.item(i); // Process node data ... } 2. Use the XSLT converter to convert XML documents: // Import jaxp -related classes import javax.xml.transform.TransformerFactory; import javax.xml.transform.Transformer; import javax.xml.transform.Source; import javax.xml.transform.Result; import javax.xml.transform.stream.StreamSource; import javax.xml.transform.stream.StreamResult; // Create transformerFactory objects TransformerFactory factory = TransformerFactory.newInstance(); // Create Transformer Object Transformer transformer = factory.newTransformer(new StreamSource("stylesheet.xsl")); // Create a source object Source input = new StreamSource("input.xml"); // Create a Result object Result output = new StreamResult("output.xml"); // Execute XML conversion transformer.transform(input, output); In short, the Java API For XML Processing is a powerful XML processing framework. It provides rich functions through parsers, document object models and converters to analyze, generate, convey, and verify XML documents to facilitate developers processing and operating XML data.Essence