In -depth analysis of the HTML parser framework in the Java library
In -depth analysis of the HTML parser framework in the Java library
Brief introduction
HTML parser is one of the tools commonly used in web development. It can resolve the HTML document into a data structure that can be used for program operations.In Java, there are many types of libraries that provide powerful and flexible HTML parser frameworks. This article will deeply analyze several commonly used Java class libraries and demonstrate its usage through code examples.
1. Jsoup
JSOUP is a Java -based HTML parsing library. It provides a set of APIs that are easy to use, which can easily extract and operate data from HTML.The following is a simple example code, which demonstrates the process of using JSOUP to analyze HTML and obtain element content:
String html = "<html><head><title>Jsoup示例</title></head>"
+ "<body> <div ID = 'Content'> This is a sample content </div> </body> </html>" ";;
Document doc = Jsoup.parse(html);
Element divElement = doc.getElementById("content");
String content = divElement.text();
System.out.println (Content); // Output: "This is a sample content"
2. HTML Parser
HTML Parser is another popular Java HTML parsing library, which provides rich functions and flexible APIs.The following example code shows how to use HTML Parser to resolve HTML and extract the hyperlink content:
String html = "<html> <body> <a href='https://www.example.com'> Example link
Parser parser = new Parser();
parser.setInputHTML(html);
NodeList nodeList = parser.parse(null);
NodeFilter filter = new TagNameFilter("a");
NodeList filteredList = nodeList.extractAllNodesThatMatch(filter, true);
LinkTag linkTag = (LinkTag) filteredList.elementAt(0);
String link = linkTag.getLinkText();
System.out.println (link); // Output: "Example link"
3. TagSoup
Tagsoup is an open source HTML parsing gallery, which is specially used to handle HTML of "non -standard" or "broken".It can analyze various irregular HTML documents and convert it into a standard XML format.The following is an example code that shows how to use Tagsoup to analyze and repair the damaged HTML:
String html = "<html> <body> <h1> Damage title </h2> </body> </html>" "";;;
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser saxParser = new SAXParser(spf.newSAXParser());
TagSoupParser tagSoupParser = new TagSoupParser();
saxParser.setContentHandler(tagSoupParser);
saxParser.setFeature(TagSoupParser.CLEAN_NAMESPACES_FEATURE, true);
saxParser.parse(new InputSource(new StringReader(html)));
String fixedHtml = tagSoupParser.getFixedHTML();
System.out.println (fixedhtml); // Output: "<html> <body> <h1> Damage title </h1> </body> </html>" "" ""
in conclusion
In the Java class library, there are many powerful and flexible HTML parser frameworks to choose from.This article introduces several commonly used parsing library and demonstrates its basic usage through code examples.By understanding and using these frameworks, developers can easily extract and process data in HTML documents to provide richer functions for Web development.
