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Java中富文本转markdown

news 来源：原创 2024/5/12 15:09:09

实现富文本即html语法转md，要求是尽可能展示效果一样，可以有少许误差，另外只实现了html中的body转md，其他标签如head等未实现。

大致思路是：通过jsoup工具获取html节点，再穷举替换。前提是熟悉html以及md语法

依赖如下：

        <dependency><groupId>org.jsoup</groupId><artifactId>jsoup</artifactId><version>1.16.1</version></dependency>

代码如下：

import lombok.Data;
import org.apache.commons.lang3.StringUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;import java.util.ArrayList;
import java.util.List;public class Html2MarkdownUtil {public static void main(String[] args) {String html = "<p style=\"padding: 0; margin: 10px 0; line-height: 1.5; font-size: 16px;\"><b style=\"padding: 0; margin: 0;\">Hello<font color=\"#c24f4a\" style=\"padding: 0; margin: 0;\">world</font></b></p>";System.out.println(parseHtml2Markdown(html));}/*** 解析html2md** @param html html* @return {@link String}*/public static String parseHtml2Markdown(String html) {Document doc = Jsoup.parse(html);StringBuilder sb = new StringBuilder();for (Element element : doc.body().children()) {HtmlElement htmlElement = new HtmlElement(element);sb.append(htmlElement.getMarkdownText());}return sb.toString();}/*** 标记文本** @param element 要素* @return {@link String}*/public static String toMarkdownText(Element element) {StringBuilder sb = new StringBuilder();String tagName = element.tagName().toLowerCase();String text = element.ownText();switch (tagName) {case "h1":sb.append("# ").append(text);break;case "h2":sb.append("## ").append(text);break;case "h3":sb.append("### ").append(text);break;case "h4":sb.append("#### ").append(text);break;case "h5":sb.append("##### ").append(text);break;case "h6":sb.append("###### ").append(text);break;case "p":case "font":case "b":case "span":sb.append(text);break;case "ul":for (Element child : element.children()) {sb.append("* ").append(child.text().trim()).append("\n");}break;case "ol":int index = 1;for (Element child : element.children()) {sb.append(index).append(". ").append(child.text().trim()).append("\n");index++;}break;case "a":sb.append("[").append(text).append("](").append(element.attr("href")).append(")");break;case "strong":sb.append("**").append(text).append("**");break;case "em":sb.append("_").append(text).append("_");break;case "blockquote":sb.append("> ").append(text);break;case "img":sb.append("![");if (element.hasAttr("alt")) {sb.append(element.attr("alt"));}sb.append("](").append(element.attr("src")).append(")");break;default:break;}return sb.toString();}@Datapublic static class HtmlElement {private Element element;private String tagName;private String ownText;private boolean isNewline;private List<HtmlElement> children;public HtmlElement(Element element) {this.element = element;this.tagName = element.tagName().toLowerCase();this.ownText = element.ownText();this.isNewline = isNewline();if (!StringUtils.equalsAny(this.tagName, "ul", "ol")) {Elements children = element.children();if (children.size() > 0) {this.children = new ArrayList<>();for (Element child : children) {this.children.add(new HtmlElement(child));}}}}public boolean isNewline() {return StringUtils.equalsAny(tagName, "h1", "h2", "h3", "h4", "h5", "h6", "p", "ul", "ol", "blockquote");}public String getMarkdownText() {StringBuilder sb = new StringBuilder();sb.append(toMarkdownText(element));if (children != null && children.size() > 0) {for (HtmlElement child : children) {sb.append(child.getMarkdownText());}}if (isNewline) {sb.append("\n");}return sb.toString();}}
}