The application scenario of the HTMLPARSER framework in the Java library
The HTMLPARSER framework is a Java class library for parsing and processing HTML documents. It provides a convenient way to extract, operate, and convert data in HTML.It can play an important role in many application scenarios. The following are some common application scenarios and corresponding Java code examples.
1. Network crawler: HTMLPARSER can help developers climb online and extract the required data from the webpage.By analyzing the HTML mark, you can extract information such as title, text, links, pictures.
import org.htmlparser.Parser;
import org.htmlparser.util.NodeList;
import org.htmlparser.tags.LinkTag;
import org.htmlparser.util.ParserException;
public class WebCrawler {
public static void main(String[] args) {
try {
// Create Parser objects and specify URL
Parser parser = new Parser("http://example.com");
// Get all link tags
NodeList list = parser.extractAllNodesThatMatch(node -> node instanceof LinkTag);
for (int i = 0; i < list.size(); i++) {
LinkTag link = (LinkTag) list.elementAt(i);
System.out.println("Link: " + link.getLink());
}
} catch (ParserException e) {
e.printStackTrace();
}
}
}
2. Data extraction and conversion: HTMLPARSER can help developers extract specific data from HTML and convert it into a suitable format.This is very useful for data mining, text analysis and information extraction.
import org.htmlparser.Parser;
import org.htmlparser.util.NodeList;
import org.htmlparser.tags.TableColumn;
import org.htmlparser.util.ParserException;
public class DataExtraction {
public static void main(String[] args) {
try {
// Create Parser objects and specify HTML content
Parser parser = new Parser("<table><tr><td>Hello</td><td>World</td></tr></table>");
// Getting all the table columns tags
NodeList list = parser.extractAllNodesThatMatch(node -> node instanceof TableColumn);
for (int i = 0; i < list.size(); i++) {
TableColumn column = (TableColumn) list.elementAt(i);
System.out.println("Column: " + column.toPlainTextString());
}
} catch (ParserException e) {
e.printStackTrace();
}
}
}
3. Data cleaning and processing: HTMLPARSER can help developers clean up and process HTML documents.It provides rich APIs to delete irrelevant marks, format texts, and process special characters.
import org.htmlparser.Parser;
import org.htmlparser.util.NodeIterator;
import org.htmlparser.util.NodeList;
import org.htmlparser.tags.BodyTag;
import org.htmlparser.util.ParserException;
public class DataCleaning {
public static void main(String[] args) {
try {
// Create Parser objects and specify HTML content
Parser parser = new Parser("<html><body><p>Hello <b>World!</b></p></body></html>");
// Get all body tags
NodeList list = parser.extractAllNodesThatMatch(node -> node instanceof BodyTag);
if (list.size() > 0) {
BodyTag bodyTag = (BodyTag) list.elementAt(0);
// Delete all sub -nodes
NodeIterator iterator = bodyTag.getChildren().elements();
while (iterator.hasMoreNodes()) {
iterator.nextNode().getParent().removeChild(iterator.nextNode());
}
System.out.println("Cleaned HTML: " + bodyTag.toPlainTextString());
}
} catch (ParserException e) {
e.printStackTrace();
}
}
}
In short, the HTMLPARSER framework can be widely used in the JAVA class library in the Java library, which can be widely used in network crawlers, data extraction and conversion, data cleaning and processing.Through this framework, developers can easily analyze and process HTML documents and extract the required data from them.
