The working principle of the ATTOPARSER framework in the Java class library

Attoparser is a Java class library for analysis and processing HTML/XML documents.It is based on Apache Xercess and Antlr technology, and aims to provide a reliable and efficient parster to process HTML and XML files in Web development. The working principle of Attoparser is as follows: 1. Read document: Use Attoparser, we first need to obtain HTML/XML documents from files, string or networks.You can use Java input stream reading files, or use the HTTP client to obtain documents from the web server. File inputFile = new File("document.html"); Document doc = Jsoup.parse(inputFile, "UTF-8", "http://example.com/"); 2. Analysis document: Once we get the document, we can use Attoparser to start parsing.ATTOPARSER uses an event -based analysis model. It reads the label, attributes and text nodes in the document one by one, and generates corresponding events.We can register for appropriate processing procedures to handle these events. ParserDelegator parser = new ParserDelegator(); parser.parse(new StringReader(html), handler, true); 3. Processing event: In the analysis process, Attoparser will generate the following types of events: start labels, end labels, text, annotations, etc.We can realize the custom processor as needed to handle these events. class MyHandler extends DefaultHandler { public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { // Treat the start label event } public void endElement(String uri, String localName, String qName) throws SAXException { // Treatment the end label event } public void characters(char ch[], int start, int length) throws SAXException { // Treatment text events } } 4. Extract data: When processing the event, you can extract information from the HTML/XML document as needed.For example, we can extract the attribute values of specific tags, text content, etc. public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { if (qName.equalsIgnoreCase("a")) { String href = attributes.getValue("href"); // Extract the href attribute value in the <a> label } } 5. Complete analysis: Once the document is fully analyzed, we can perform some cleaning or processing work and close relevant resources. parser.finish(); Summarize: Attoparser is a powerful and easy -to -use Java class library for analysis and processing HTML/XML documents.It provides a reliable and efficient method to handle the HTML and XML files in Web development by reading the nodes in the document and generating the corresponding events one by one.Developers can use custom event processing procedures to extract data or perform other operations as needed to make it an ideal choice for handling Web documents.