HTML parser: introduction and envoy in the Java class library
HTML parser is a tool to analyze HTML documents and extract information.In the Java class library, there are many excellent HTML parsers to use.This article will introduce several commonly used Java libraries and provide some example code to show their usage and functions.
1. Jsoup:
JSOUP is a very popular HTML parser, which analyzes HTML documents in a simple and intuitive way.It provides rich APIs that can easily handle HTML elements, attributes and text content.The following is an example of using JSOUP to analyze HTML and extract links:
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
public class JsoupExample {
public static void main(String[] args) throws Exception {
String html = "<html><body><div><a href='https://www.example.com'>Example</a></div></body></html>";
Document document = Jsoup.parse(html);
Elements links = document.select("a[href]");
for (Element link : links) {
System.out.println("Link: " + link.attr("href"));
System.out.println("Text: " + link.text());
}
}
}
2. HTML Cleaner:
HTML Cleaner is another popular HTML parser that can clean up and format HTML documents and provide simple APIs to navigate and extract data.The following is an example of using HTML Cleaner to resolve HTML and extract the label content:
import org.htmlcleaner.HtmlCleaner;
import org.htmlcleaner.TagNode;
import org.htmlcleaner.XPatherException;
public class HtmlCleanerExample {
public static void main(String[] args) throws Exception {
String html = "<html><body><div><h1>Title</h1><p>Content</p></div></body></html>";
HtmlCleaner cleaner = new HtmlCleaner();
TagNode node = cleaner.clean(html);
Object[] titleNodes = node.evaluateXPath("//h1");
if (titleNodes.length > 0) {
TagNode titleNode = (TagNode) titleNodes[0];
System.out.println("Title: " + titleNode.getText().toString());
}
Object[] contentNodes = node.evaluateXPath("//p");
for (Object contentNode : contentNodes) {
TagNode pTag = (TagNode) contentNode;
System.out.println("Content: " + pTag.getText().toString());
}
}
}
3. Jericho HTML Parser:
Jericho HTML Parser is a fast, flexible and easy -to -use HTML parser that can resolve, modify and build HTML documents.The following is an example of using Jericho HTML Parser to analyze HTML and extract the picture link:
import net.htmlparser.jericho.Element;
import net.htmlparser.jericho.Source;
import java.util.List;
public class JerichoHtmlParserExample {
public static void main(String[] args) throws Exception {
String html = "<html><body><div><img src='image.jpg' alt='Image'></div></body></html>";
Source source = new Source(html);
List<Element> imgElements = source.getAllElements("img");
for (Element imgElement : imgElements) {
System.out.println("Image URL: " + imgElement.getAttributeValue("src"));
System.out.println("Alternative Text: " + imgElement.getAttributeValue("alt"));
}
}
}
These example code demonstrates the usage of three commonly used Java HTML parsers.According to specific needs, you can choose a suitable parser to analyze and extract data in HTML documents.I hope this article can help you better understand and use the HTML parser.
