1.在build.gradle中安装所需依赖：

implementation group: 'com.itextpdf', name: 'itextpdf', version: '5.5.13'
implementation group: 'com.itextpdf.tool', name: 'xmlworker', version: '5.5.13'
implementation group: 'org.jsoup', name: 'jsoup', version: '1.15.3'

2.创建工具类，实现转换方法

/*** convert the html to pdf.*/public void htmlToPdf(String oldFilePath, String newFilePath) throws IOException, com.itextpdf.text.DocumentException {Document doc = Jsoup.parse(new File(oldFilePath), "UTF-8");// jsoup标准化标签，生成闭合标签doc.outputSettings().syntax(org.jsoup.nodes.Document.OutputSettings.Syntax.xml);doc.outputSettings().escapeMode(Entities.EscapeMode.xhtml);com.itextpdf.text.Document document = new com.itextpdf.text.Document(PageSize.A4, 36, 36, 36, 36);PdfWriter pdfWriter = PdfWriter.getInstance(document, new FileOutputStream(newFilePath));document.open();//html to pdf, base64 image support.final TagProcessorFactory tagProcessorFactory = Tags.getHtmlTagProcessorFactory();tagProcessorFactory.removeProcessor(HTML.Tag.IMG);tagProcessorFactory.addProcessor(new ImageTagRefreshFilter(), HTML.Tag.IMG);//设置中文字体final CssFilesImpl cssFiles = new CssFilesImpl();cssFiles.add(XMLWorkerHelper.getInstance().getDefaultCSS());final StyleAttrCSSResolver cssResolver = new StyleAttrCSSResolver(cssFiles);final HtmlPipelineContext hpc = new HtmlPipelineContext(new CssAppliersImpl(asianFontRefreshFilter));hpc.setAcceptUnknown(true).autoBookmark(true).setTagFactory(tagProcessorFactory);final HtmlPipeline htmlPipeline = new HtmlPipeline(hpc, new PdfWriterPipeline(document, pdfWriter));final Pipeline<?> pipeline = new CssResolverPipeline(cssResolver, htmlPipeline);final XMLWorker worker = new XMLWorker(pipeline, true);final Charset charset = StandardCharsets.UTF_8;final XMLParser xmlParser = new XMLParser(true, worker, charset);InputStream inputStream = new ByteArrayInputStream(doc.html().getBytes());xmlParser.parse(inputStream, charset);
//        XMLWorkerHelper.getInstance().parseXHtml(pdfWriter, document, inputStream, Charset.forName("UTF-8"));document.close();}

3.base64过滤类：

import com.itextpdf.text.Chunk;
import com.itextpdf.text.Element;
import com.itextpdf.text.Image;
import com.itextpdf.text.pdf.codec.Base64;
import com.itextpdf.tool.xml.NoCustomContextException;
import com.itextpdf.tool.xml.Tag;
import com.itextpdf.tool.xml.WorkerContext;
import com.itextpdf.tool.xml.exceptions.RuntimeWorkerException;
import com.itextpdf.tool.xml.html.HTML;
import com.itextpdf.tool.xml.pipeline.html.HtmlPipelineContext;public class ImageTagRefreshFilter extends com.itextpdf.tool.xml.html.Image {/*** html to pdf, base64 image support.* */@Overridepublic List<Element> end(final WorkerContext ctx, final Tag tag, final List<Element> currentContent) {final Map<String, String> attributes = tag.getAttributes();String src = attributes.get(HTML.Attribute.SRC);List<Element> elements = new ArrayList<Element>(1);if (null != src && src.length() > 0) {Image img = null;if (src.startsWith("data:image/")) {final String base64Data = src.substring(src.indexOf(",") + 1);try {img = Image.getInstance(Base64.decode(base64Data));} catch (Exception e) {throw new RuntimeException(e);}if (img != null) {try {final HtmlPipelineContext htmlPipelineContext = getHtmlPipelineContext(ctx);elements.add(getCssAppliers().apply(new Chunk((com.itextpdf.text.Image) getCssAppliers().apply(img, tag, htmlPipelineContext), 0, 0, true), tag,htmlPipelineContext));} catch (NoCustomContextException e) {throw new RuntimeWorkerException(e);}}}if (img == null) {elements = super.end(ctx, tag, currentContent);}}return elements;}
}

4.字体类代码，window用户可在C:\windows\font\中寻找自己所需字体即可。我这里用的为黑体：

simhei.ttf

import com.itextpdf.text.Font;
import com.itextpdf.text.pdf.BaseFont;
import com.itextpdf.tool.xml.XMLWorkerFontProvider;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;@Component
public class AsianFontRefreshFilter extends XMLWorkerFontProvider {//此处写字体文件的绝对路径private String fontPath;@Overridepublic Font getFont(String fontname, String encoding, float size, final int style) {try {//字体文件绝对路径BaseFont bfChinese = BaseFont.createFont(fontPath, BaseFont.IDENTITY_H, BaseFont.EMBEDDED);return new Font(bfChinese, size, style);} catch (Exception e) {e.printStackTrace();}return super.getFont(fontname, encoding, size, style);}
}

效果如下：

html页面预览：

pdf页面预览：