commonmark-java 是一个用于解析和渲染 Markdown 文本的 Java 库;本文主要介绍其基本使用,文中所使用到的软件版本:Java 17.0.5、commonmark-java 0.25.1。
commonmark-java 可以用来解析抽象语法树(AST),访问和操作其节点,以及生成 HTML 或 Markdown。它最初是 commonmark.js 的移植版,但后来发展成为一个可扩展的库,具备以下特点:
pegdown 快 10 到 20 倍)commonmark-java 需要使用 Java 11 及以上版本。
解析 Markdown 时使用该样例文件。
test.md<dependency> <groupId>org.commonmark</groupId> <artifactId>commonmark</artifactId> <version>0.26.0</version></dependency><dependency> <groupId>org.commonmark</groupId> <artifactId>commonmark-ext-gfm-tables</artifactId> <version>0.26.0<version></dependency>
@Testpublic void serialize() {
Document document = new Document();
Heading heading = new Heading();
heading.setLevel(2);
heading.appendChild(new Text("1 Markdown语法教程"));
document.appendChild(heading);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.1 标题"));
document.appendChild(heading);
Paragraph paragraph = new Paragraph();
paragraph.appendChild(new Text("不同数量的"));
paragraph.appendChild(new Code("#"));
paragraph.appendChild(new Text("可以完成不同的标题,如下:"));
document.appendChild(paragraph);
heading = new Heading();
heading.setLevel(1);
heading.appendChild(new Text("一级标题"));
document.appendChild(heading);
heading = new Heading();
heading.setLevel(2);
heading.appendChild(new Text("二级标题"));
document.appendChild(heading);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("三级标题"));
document.appendChild(heading);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.2 字体"));
document.appendChild(heading);
paragraph = new Paragraph();
paragraph.appendChild(new Text("粗体、斜体、粗体和斜体,删除线,需要在文字前后加不同的标记符号。如下:"));
document.appendChild(paragraph);
paragraph = new Paragraph();
StrongEmphasis strongEmphasis = new StrongEmphasis();
strongEmphasis.appendChild(new Text("这个是粗体"));
paragraph.appendChild(strongEmphasis);
document.appendChild(paragraph);
paragraph = new Paragraph();
Emphasis emphasis = new Emphasis("*");
emphasis.appendChild(new Text("这个是斜体"));
paragraph.appendChild(emphasis);
document.appendChild(paragraph);
paragraph = new Paragraph();
strongEmphasis = new StrongEmphasis();
emphasis = new Emphasis("*");
emphasis.appendChild(new Text("这个是粗体加斜体"));
strongEmphasis.appendChild(emphasis);
paragraph.appendChild(strongEmphasis);
document.appendChild(paragraph);
paragraph = new Paragraph();
paragraph.appendChild(new Text("~~这里是删除线~~"));
document.appendChild(paragraph);
paragraph = new Paragraph();
paragraph.appendChild(new Text("注:如果想给字体换颜色、字体或者居中显示,需要使用内嵌HTML来实现。"));
document.appendChild(paragraph);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.3 无序列表"));
document.appendChild(heading);
paragraph = new Paragraph();
paragraph.appendChild(new Text("无序列表的使用,在符号"));
paragraph.appendChild(new Code("-"));
paragraph.appendChild(new Text("后加空格使用。如下:"));
document.appendChild(paragraph);
BulletList bulletList = new BulletList();
ListItem listItem = new ListItem();
listItem.appendChild(new Text("无序列表 1"));
bulletList.appendChild(listItem);
bulletList.appendChild(new SoftLineBreak());
listItem = new ListItem();
listItem.appendChild(new Text("无序列表 2"));
bulletList.appendChild(listItem);
bulletList.appendChild(new SoftLineBreak());
listItem = new ListItem();
listItem.appendChild(new Text("无序列表 3"));
bulletList.appendChild(listItem);
document.appendChild(bulletList);
paragraph = new Paragraph();
paragraph.appendChild(new Text("如果要控制列表的层级,则需要在符号"));
paragraph.appendChild(new Code("-"));
paragraph.appendChild(new Text("前使用空格。如下:"));
document.appendChild(paragraph);
bulletList = new BulletList();
listItem = new ListItem();
listItem.appendChild(new Text("无序列表 1"));
bulletList.appendChild(listItem);
bulletList.appendChild(new SoftLineBreak());
listItem = new ListItem();
listItem.appendChild(new Text("无序列表 2"));
bulletList.appendChild(listItem);
bulletList.appendChild(new SoftLineBreak());
BulletList bulletList2 = new BulletList();
listItem = new ListItem();
listItem.setMarkerIndent(2);
listItem.appendChild(new Text("无序列表 2.1"));
bulletList2.appendChild(listItem);
bulletList2.appendChild(new SoftLineBreak());
listItem = new ListItem();
listItem.setMarkerIndent(2);
listItem.appendChild(new Text("无序列表 2.2"));
bulletList2.appendChild(listItem);
bulletList.appendChild(bulletList2);
document.appendChild(bulletList);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.4 有序列表"));
document.appendChild(heading);
paragraph = new Paragraph();
paragraph.appendChild(new Text("有序列表的使用,在数字及符号"));
paragraph.appendChild(new Code("."));
paragraph.appendChild(new Text("后加空格后输入内容,如下:"));
document.appendChild(paragraph);
OrderedList orderedList = new OrderedList();
listItem = new ListItem();
listItem.appendChild(new Text("有序列表 1"));
orderedList.appendChild(listItem);
orderedList.appendChild(new SoftLineBreak());
listItem = new ListItem();
listItem.appendChild(new Text("有序列表 2"));
orderedList.appendChild(listItem);
orderedList.appendChild(new SoftLineBreak());
listItem = new ListItem();
listItem.appendChild(new Text("有序列表 3"));
orderedList.appendChild(listItem);
document.appendChild(orderedList);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.5 引用"));
document.appendChild(heading);
paragraph = new Paragraph();
paragraph.appendChild(new Text("引用的格式是在符号"));
paragraph.appendChild(new Code(">"));
paragraph.appendChild(new Text("后面书写文字。如下:"));
document.appendChild(paragraph);
BlockQuote blockQuote = new BlockQuote();
blockQuote.appendChild(new Text("读一本好书,就是在和高尚的人谈话。 ——歌德"));
document.appendChild(blockQuote);
blockQuote = new BlockQuote();
blockQuote.appendChild(new Text("雇用制度对工人不利,但工人根本无力摆脱这个制度。 ——阮一峰"));
document.appendChild(blockQuote);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.7 链接"));
document.appendChild(heading);
paragraph = new Paragraph();
paragraph.appendChild(new Text("微信公众号仅支持公众号文章链接,即域名为"));
paragraph.appendChild(new Code("https://mp.weixin.qq.com/"));
paragraph.appendChild(new Text("的合法链接。使用方法如下所示:"));
document.appendChild(paragraph);
paragraph = new Paragraph();
Link link = new Link("https://mp.weixin.qq.com/s/s5IhxV2ooX3JN_X416nidA", null);
link.appendChild(new Text("你是《未来世界的幸存者》么?"));
paragraph.appendChild(new Text("对于该论述,欢迎读者查阅之前发过的文章,"));
paragraph.appendChild(link);
document.appendChild(paragraph);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.8 图片"));
document.appendChild(heading);
paragraph = new Paragraph();
paragraph.appendChild(new Text("插入图片,格式如下:"));
document.appendChild(paragraph);
paragraph = new Paragraph();
Image image = new Image("https://markdown.com.cn/images/qrcode_for_gh_82cf87d482f0_258.jpg", null);
image.appendChild(new Text("这里写图片描述"));
paragraph.appendChild(image);
document.appendChild(paragraph);
paragraph = new Paragraph();
paragraph.appendChild(new Text("支持 jpg、png、gif、svg 等图片格式,"));
emphasis = new Emphasis("**");
emphasis.appendChild(new Text("其中 svg 文件仅可在微信公众平台中使用"));
paragraph.appendChild(emphasis);
paragraph.appendChild(new Text(",svg 文件示例如下:"));
document.appendChild(paragraph);
paragraph = new Paragraph();
image = new Image("tiyu.gov.cn.jnhjpj.cn", null);
paragraph.appendChild(image);
document.appendChild(paragraph);
paragraph = new Paragraph();
paragraph.appendChild(new Text("支持图片"));
strongEmphasis = new StrongEmphasis();
strongEmphasis.appendChild(new Text("拖拽和截图粘贴"));
paragraph.appendChild(strongEmphasis);
paragraph.appendChild(new Text("到编辑器中。"));
document.appendChild(paragraph);
paragraph = new Paragraph();
paragraph.appendChild(new Text("注:支持图片 "));
strongEmphasis = new StrongEmphasis();
emphasis = new Emphasis("*");
emphasis.appendChild(new Text("拖拽和截图粘贴"));
strongEmphasis.appendChild(emphasis);
paragraph.appendChild(strongEmphasis);
paragraph.appendChild(new Text(" 到编辑器中,仅支持 https 的图片,图片粘贴到微信时会自动上传微信服务器。"));
document.appendChild(paragraph);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.9 分割线"));
document.appendChild(heading);
paragraph = new Paragraph();
paragraph.appendChild(new Text("可以在一行中用三个以上的减号来建立一个分隔线,同时需要在分隔线的上面空一行。如下:"));
document.appendChild(paragraph);
ThematicBreak thematicBreak = new ThematicBreak();
thematicBreak.setLiteral("---");
document.appendChild(thematicBreak);
heading = new Heading();
heading.setLevel(3);
heading.appendChild(new Text("1.10 表格"));
document.appendChild(heading);
paragraph = new Paragraph();
paragraph.appendChild(new Text("可以使用冒号来定义表格的对齐方式,如下:"));
document.appendChild(paragraph);
TableBlock tableBlock = new TableBlock();
TableHead tableHead = new TableHead();
TableRow tableRow = new TableRow();
TableCell tableCell = new TableCell();
tableCell.appendChild(new Text("姓名"));
tableCell.setAlignment(TableCell.Alignment.LEFT);
tableRow.appendChild(tableCell);
tableCell = new TableCell();
tableCell.appendChild(new Text("年龄"));
tableCell.setAlignment(TableCell.Alignment.CENTER);
tableRow.appendChild(tableCell);
tableCell = new TableCell();
tableCell.appendChild(new Text("工作"));
tableCell.setAlignment(TableCell.Alignment.RIGHT);
tableRow.appendChild(tableCell);
tableHead.appendChild(tableRow);
TableBody tableBody = new TableBody();
tableRow = new TableRow();
tableCell = new TableCell();
tableCell.appendChild(new Text("小可爱"));
tableRow.appendChild(tableCell);
tableCell = new TableCell();
tableCell.appendChild(new Text("18"));
tableRow.appendChild(tableCell);
tableCell = new TableCell();
tableCell.appendChild(new Text("吃可爱多"));
tableRow.appendChild(tableCell);
tableBody.appendChild(tableRow);
tableRow = new TableRow();
tableCell = new TableCell();
tableCell.appendChild(new Text("小小勇敢"));
tableRow.appendChild(tableCell);
tableCell = new TableCell();
tableCell.appendChild(new Text("20"));
tableRow.appendChild(tableCell);
tableCell = new TableCell();
tableCell.appendChild(new Text("爬棵勇敢树"));
tableRow.appendChild(tableCell);
tableBody.appendChild(tableRow);
tableRow = new TableRow();
tableCell = new TableCell();
tableCell.appendChild(new Text("小小小机智"));
tableRow.appendChild(tableCell);
tableCell = new TableCell();
tableCell.appendChild(new Text("22"));
tableRow.appendChild(tableCell);
tableCell = new TableCell();
tableCell.appendChild(new Text("看一本机智书"));
tableRow.appendChild(tableCell);
tableBody.appendChild(tableRow);
tableBlock.appendChild(tableHead);
tableBlock.appendChild(tableBody);
document.appendChild(tableBlock);
List<Extension> extensions = List.of(TablesExtension.create());
MarkdownRenderer markdownRenderer = MarkdownRenderer.builder(www.tiyu.gov.cn.jnhjpj.cn).extensions(extensions).build(); //转成markdown格式
String md = markdownRenderer.render(document);
System.out.println(md);
HtmlRenderer htmlRenderer = HtmlRenderer.builder().extensions(extensions).build(); //转成html
String html = htmlRenderer.render(document);
System.out.println(html);
}
@Testpublic void deserialize() throws IOException {
List<Extension> extensions = List.of(TablesExtension.create());
Parser parser = Parser.builder(m.jnhjpj.cn).extensions(extensions).build();
InputStreamReader reader = new InputStreamReader(CommonmarkCase.class.getClassLoader().getResourceAsStream("test.md"));
Node document = parser.parseReader(reader);
Node node = document.getFirstChild(); while (node != null) {
System.out.println(node.getClass()); if (node.getClass().equals(Heading.class)) {//处理标题
Heading heading = (Heading) node;
Text text = (Text)heading.getFirstChild();
System.out.println wap.jnhjpj.cn (text.getLiteral());
} else if (node.getClass().equals(BulletList.class)) {//处理无序列表
BulletList bulletList = (BulletList) node;
Node node2 = bulletList.getFirstChild(); while (node2 != null) { if (node2.getClass().equals(ListItem.class)) {
Node node3 = node2.getFirstChild(); if (node3.getClass().equals(Paragraph.class)) {
Text text = (Text)node3.getFirstChild();
System.out.println(text.getLiteral());
} if (node3.getNext() != null && node3.getNext().getClass(tiyu.gov.cn.huadasp.cn).equals(BulletList.class)) {
System.out.println("二级无序列表"); //TODO: 继续解析 }
}
node2 = node2.getNext();
}
} //else if ...
node = node.getNext();
}
}
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