The technical principles of JSR173 API framework in the Java library detailed explanation
The JSR173 API framework is a common technology in the Java library. It provides a convenient way to process XML data.In this article, we will explore the technical principles of the JSR173 API framework and provide relevant Java code examples.
1. What is the JSR173 API framework?
The JSR173 API framework is a XML processing technology in the Java Standard Edition (Java SE), which is called "Java Specification Request 173".It defines a set of interfaces and classes used to analyze, generate and operate XML documents.The JSR173 API is a lightweight XML processing method. It does not need to rely on complex XML parser or traditional XML processing technology such as DOM/SAX.
2. The technical principle of the JSR173 API framework
The JSR173 API framework is based on an event -driven XML processing model. It processs XML data by converting XML documents into a series of events.Developers can listen to these events through registered event processors and take corresponding operations at appropriate.The following is the general workflow of the JSR173 API framework:
-Colon a XML document to be treated with XML input source and specify.
-Colon an event reader (EventReader), which is responsible for analyzing XML documents and converting it into an event stream.
-In the use of event readers to read the event flow, obtain different types of events including element start, element end, character data and other types of events.
-Che corresponding operations according to the type of event, such as extracting the attribute values of the element, the text content of obtaining the element.
-In the same, you can create an event writer to generate XML documents.
3. Code example of the JSR173 API framework
Now, let's understand the use of the JSR173 API framework through a simple code example.Suppose we have a XML file called "Books.xml", which contains some books information.We want to use the JSR173 API framework to analyze the XML file and print the title and author of each book.
First of all, we need to introduce related class libraries for the JSR173 API framework.You can use maven and other construction tools to add the following dependencies to the pom.xml file in the project:
<dependency>
<groupId>javax.xml.stream</groupId>
<artifactId>stax-api</artifactId>
<version>1.0-2</version>
</dependency>
Next, we use the following java code to analyze the title and author of the "Books.xml" file and print the book:
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamReader;
import java.io.FileInputStream;
import java.io.InputStream;
public class XMLParser {
private static final String XML_FILE = "books.xml";
public static void main(String[] args) {
try {
InputStream inputStream = new FileInputStream(XML_FILE);
XMLInputFactory factory = XMLInputFactory.newInstance();
XMLStreamReader reader = factory.createXMLStreamReader(inputStream);
String title = "";
String author = "";
while (reader.hasNext()) {
int event = reader.next();
switch (event) {
case XMLStreamConstants.START_ELEMENT:
if ("title".equals(reader.getLocalName())) {
title = reader.getElementText();
} else if ("author".equals(reader.getLocalName())) {
author = reader.getElementText();
}
break;
case XMLStreamReader.END_ELEMENT:
if ("book".equals(reader.getLocalName())) {
System.out.println("Title: " + title);
System.out.println("Author: " + author);
System.out.println("----------------------");
}
break;
}
}
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
In the above example, we use the XMLSTREAMREADER class to read the event flow of the XML document.Through iterative reading incidents, we extracted text contents of the elements of "Title" and "Author" and printed them.Note that when the "Book" element ended the label, we print a complete book information.
4. Summary
The JSR173 API framework is a common technology used in the Java class library to process XML data.It is based on event -driven XML processing model and operates XML data by converting XML documents into event flows and monitoring related events.In this article, we discussed the technical principles of the JSR173 API framework in detail, and provided a simple code example to analyze the XML document and extract information.It is hoped that this article can better understand and use the JSR173 API framework.
