JSR173 API's technical principles in the Java class library
JSR 173 API's technical principles in the Java class library explore
introduction:
Java API For XML Processing (JAXP) is a standard API for the XML on the Java platform. It provides flexible and easy -to -use methods to analyze, create and operate XML documents.JSR 173 API is part of JAXP, which defines a set of generals for handling XML and an API independent of manufacturers.This article will explore the technical principles of the JSR 173 API in the Java class library and provide relevant Java code examples.
JSR 173 API Overview:
JSR 173 API is the abbreviation of Java Specification Requests. It is part of Java Community Process (JCP), which aims to formulate and update technical standards related to the Java platform.The JSR 173 defines a set of APIs for XML, which can analyze and build XML documents, and access and modify the XML document.
JSR 173 API technical principle:
The JSR 173 API is an event -based API that adopts a method of streaming processing.It uses events as the basic unit and processs XML data by triggering different types of events by parsing XML documents.
1. xmlReader interface:
The XMLREADER interface is the core interface of the JSR 173 API, which defines the registration mechanism to analyze the method of XML documents and event processors.The implementation class of the XMLREADER interface is responsible for reading the XML document and triggering the event during the analysis process.
The following is an example of a simple XMLREADER implementation:
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import java.io.FileInputStream;
import java.io.InputStream;
public class XMLParser {
public static void main(String[] args) {
try {
XMLInputFactory inputFactory = XMLInputFactory.newInstance();
InputStream input = new FileInputStream("example.xml");
XMLStreamReader reader = inputFactory.createXMLStreamReader(input);
while(reader.hasNext()){
int event = reader.next();
switch(event){
case XMLStreamReader.START_ELEMENT:
System.out.println("Start Element: " + reader.getLocalName());
break;
case XMLStreamReader.END_ELEMENT:
System.out.println("End Element: " + reader.getLocalName());
break;
case XMLStreamReader.CHARACTERS:
System.out.println("Text: " + reader.getText());
break;
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
2. Event processor:
Event processor is used to handle various events triggered by XMLREADER.JSR 173 API defines two standard event processor interfaces: ContentHandler and ErrorHandler.ContentHandler is used to handle elements, attributes and texts in XML documents, and ErrorHandler is used to handle errors and abnormalities in the parsing process.
Below is an example using ContentHandler:
import javax.xml.stream.events.StartElement;
import javax.xml.stream.events.EndElement;
import javax.xml.stream.events.Characters;
import javax.xml.stream.events.XMLEvent;
import javax.xml.stream.events.XMLEventReader;
import javax.xml.stream.XMLEventFactory;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLInputFactory;
import java.io.FileInputStream;
import java.io.InputStream;
public class XMLContentHandler {
public static void main(String[] args) {
try {
XMLInputFactory inputFactory = XMLInputFactory.newInstance();
InputStream input = new FileInputStream("example.xml");
XMLEventReader eventReader = inputFactory.createXMLEventReader(input);
while(eventReader.hasNext()){
XMLEvent event = eventReader.nextEvent();
if(event.isStartElement()){
StartElement startElement = event.asStartElement();
System.out.println("Start Element: " + startElement.getName().getLocalPart());
} else if(event.isEndElement()){
EndElement endElement = event.asEndElement();
System.out.println("End Element: " + endElement.getName().getLocalPart());
} else if(event.isCharacters()){
Characters characters = event.asCharacters();
System.out.println("Text: " + characters.getData());
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
Summarize:
The JSR 173 API provides a flexible and efficient way to handle XML documents for the Java platform.Its event -based processing method makes processing large XML documents more efficient, and provides event processors to handle different types of events.By using the JSR 173 API, developers can easily analyze, create and operate XML documents to make it suitable for various types of application development.
