Java class library JSR 173 stream API for XML reference to the original technical understanding of the realization framework
JSR 173 Stream API For XML References to the original technical understanding of the implementation framework
JSR 173 Stream API For XML Reference Implementation Framework is a Java class library used to process XML documents.It provides developers with a simple and flexible way to analyze and generate XML documents.The following is its technical principle explanation.
1. XML Analysis: JSR 173 Stream API allows developers to use the flow of XML documents.It uses an event -driven model to read each part of the XML document by the parser one by one, and trigger the corresponding event.Developers can register their own event processing procedures in order to deal with these events during the analysis process.This analysis method does not need to load the entire XML document to the memory, so it is very suitable for the processing of large XML documents.
Below is a simple example of using the JSR 173 stream API to resolve XML documents:
import javax.xml.stream.*;
import java.io.FileInputStream;
public class XMLParserExample {
public static void main(String[] args) {
try {
XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
XMLStreamReader xmlStreamReader = xmlInputFactory.createXMLStreamReader(new FileInputStream("example.xml"));
while (xmlStreamReader.hasNext()) {
int eventType = xmlStreamReader.next();
if (eventType == XMLStreamConstants.START_ELEMENT) {
String elementName = xmlStreamReader.getLocalName();
System.out.println("Start Element: " + elementName);
} else if (eventType == XMLStreamConstants.CHARACTERS) {
String text = xmlStreamReader.getText();
System.out.println("Text: " + text);
} else if (eventType == XMLStreamConstants.END_ELEMENT) {
String elementName = xmlStreamReader.getLocalName();
System.out.println("End Element: " + elementName);
}
}
xmlStreamReader.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
The above code uses XMLINPUTFACTORY to create a XMLSTREAMREADER object to resolve XML documents.We then use the WHILE cycle to iterate every event of XML stream.According to the type of event, we can perform the corresponding operations, such as obtaining element names or text content.
2. XML generation: JSR 173 stream API also allows developers to generate XML documents.Developers can use XMLSTREAMWRITER to create XML documents and add elements, attributes and text content as needed.Unlike analysis, when generating XML documents, we need to gradually build the XML structure and write the output stream.
The following is a simple example of using the JSR 173 stream API to generate XML documents:
import javax.xml.stream.*;
import java.io.FileOutputStream;
public class XMLGeneratorExample {
public static void main(String[] args) {
try {
XMLOutputFactory xmlOutputFactory = XMLOutputFactory.newInstance();
XMLStreamWriter xmlStreamWriter = xmlOutputFactory.createXMLStreamWriter(new FileOutputStream("example.xml"));
xmlStreamWriter.writeStartDocument();
xmlStreamWriter.writeStartElement("root");
xmlStreamWriter.writeStartElement("element1");
xmlStreamWriter.writeCharacters("Text content for element1");
xmlStreamWriter.writeEndElement();
xmlStreamWriter.writeStartElement("element2");
xmlStreamWriter.writeCharacters("Text content for element2");
xmlStreamWriter.writeEndElement();
xmlStreamWriter.writeEndElement();
xmlStreamWriter.writeEndDocument();
xmlStreamWriter.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
The above code uses XMLOUTPUTFACTORY to create a XMLSTREAMWRITER object to generate XML documents.We then use the WRITEXXX () method to build the XML structure.After completing the construction, we call the WritendDocument () method to end the writing of the XML document.
Summary: The reference framework of the JSR 173 stream API for XML provides a flexible and efficient way to process XML documents.By using event -driven models, developers can effectively analyze and generate large XML documents.The use of stream API can avoid loading the entire XML document into memory, thereby reducing memory consumption and improving performance.
