Understand the principle and technology of the MARKED framework in the Java class library
The Marked framework is a tool to analyze and convey the Markdown text, which is widely used in the Java library.This article will introduce the principles and implementation technology of the MARKED framework, and provide some related Java code examples.
1. Overview of the MARKED framework
The Marked framework is an excellent open source project. It can easily display and share documents by converting Markdown text into HTML, Latex and other formats.The framework supports a wide range of Markdown syntax marks and provides rich configuration options to meet different needs.
Second, the principle of the MARKED framework
The core principle of the Marked framework is based on the collaborative work of parsers and renderers.It decomposes the input Markdown text into a grammatical unit, and recognizes and analyzes the grammatical mark through parsers.The parser follows a series of parsing rules, such as title, paragraphs, lists, links, etc., and converts it into the corresponding HTML or other formats.The rendereer then rendered these resolution results into the final output.
Third, the implementation technology of the MARKED framework
1. The implementation of the parser:
The Marked framework adopts a line -by -line analysis method to read every line of text and use a series of regular expressions for matching and analysis, thereby identifying and processing the MarkDown syntax mark.
Here are a simple analyzer example to analyze and handle the title mark of Markdown:
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Parser {
private static final Pattern HEADER_PATTERN = Pattern.compile("^(#+)(.*)");
public String parseHeader(String line) {
Matcher matcher = HEADER_PATTERN.matcher(line);
if (matcher.find()) {
int level = matcher.group (1) .length (); // title level
String content = matcher.group (2) .trim (); // Title content
return "<h" + level + ">" + content + "</h" + level + ">";
}
return null;
}
}
2. Realization of the renderer:
The MARKED framework provides the default renderer to convert the Markdown syntax of the parser to HTML format.The rendereer traverses the resolution results returned by the parser and performs the corresponding HTML rendering based on different types.
The following is a simple example of rendering device. It is used to convert the title marking of Markdown to the title element of HTML:
public class Renderer {
public String renderHeader(String content, int level) {
return "<h" + level + ">" + content + "</h" + level + ">";
}
}
Finally, combine the parseper and renderer to complete the analysis and conversion of the entire Markdown text:
public class Marked {
private Parser parser;
private Renderer renderer;
public Marked() {
this.parser = new Parser();
this.renderer = new Renderer();
}
public String parse(String markdown) {
StringBuilder result = new StringBuilder();
String[] lines = markdown.split("
");
for (String line : lines) {
String header = parser.parseHeader(line);
if (header != null) {
result.append(header);
}
}
return result.toString();
}
}
Fourth, summary
The Marked framework uses the collaborative work of parsers and renderers to realize the conversion from the Markdown text to HTML and other formats.It recognizes and parsed the Markdown syntax mark, and then renders the resolution results into a final output by the renderer.This method of analysis and conversion provides us with efficient and flexible tools to show and share Markdown documents.
