在之前的文章里，有介绍如何将Html转成PDF的，详见：https://blog.terrynow.com/2021/08/10/itextpdf-5-x-convert-html-to-pdf-support-css-and-chinese/
本次又遇到一个新需求，就是Html里面有图片<img src="xxx" /> 期中xxx是http://192.168.1.1/xxx.jpg，这种链接方式的图片，发现图片是无法显示出来的，所以想办法src里面的图片转成base64的格式，例如<img src="data:image/png;base64,xxxxx" />，不过默认的情况下，iTextPDF还是无法识别并显示出来。
实现
这里，我们需要做一些特别的处理，让iTextPDF能识别这样的img格式。
新建ImageTagProcessor.java
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;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
/**
* @author Terry E-mail: yaoxinghuo at 126 dot com
* @date 2021/9/22 17:53
* @description
*/
public class ImageTagProcessor extends com.itextpdf.tool.xml.html.Image {
@Override
public 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<>(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 ignored) {
}
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;
}
}
新建AsianFontProvider.java 实现中文支持，解决中文乱码或者不显示的问题
import com.itextpdf.text.BaseColor;
import com.itextpdf.text.Font;
import com.itextpdf.text.pdf.BaseFont;
import com.itextpdf.tool.xml.XMLWorkerFontProvider;
/**
* @author Terry E-mail: yaoxinghuo at 126 dot com
* @date 2021/9/22 19:55
* @description
*/
public class AsianFontProvider extends XMLWorkerFontProvider {
private BaseFont baseFont;
private String pdfFontBold;
public AsianFontProvider(String pdfFontBasic, String pdfFontBold) {
this.baseFont = createBaseFont(pdfFontBasic);
this.pdfFontBold = pdfFontBold;
}
@Override
public Font getFont(String face, String encode, boolean b, float size, int style, BaseColor baseColor) {
BaseFont bfChinese;
// if (style == Font.BOLD) {
// bfChinese = createBaseFont("/Users/Terry/Downloads/WeiRuanYaQiHei-Bold/MicrosoftYaqiHeiBold-2.ttf");
// } else {
// bfChinese = createBaseFont("/Users/Terry/Downloads/WeiRuanYaHeiTi/WeiRuanYaHei-1.ttf");
// }
if (style == Font.BOLD) {
bfChinese = createBaseFont(pdfFontBold);
} else {
bfChinese = baseFont;
}
// System.out.println("get font called, s:" + face + ",s1:" + encode);
// BaseFont bfChinese = BaseFont.createFont("/Users/Terry/Downloads/STSong.ttf", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
// BaseFont bfChinese = BaseFont.createFont("STSongStd-Light", "UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);
return new Font(bfChinese, size, style, baseColor);
}
private static BaseFont createBaseFont(String fontDir) {
try {
return BaseFont.createFont(fontDir, BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
}
生成PDF的工具方法：
/**
* @param htmlFile 原始html文件
* @param pdfFontBasic 中文ttf字体的路径
* @param pdfFontBasic 中文ttf字体粗体的路径
* @return 这里返回的PDF我返回成了bytes，也可以稍加修改ByteArrayOutputStream改成FileOutputStream 输出到文件
*/
public static byte[] convertHtmlToPDF(String pdfFontBasic, String pdfFontBold, InputStream htmlFile) throws Exception {
Document document = new com.itextpdf.text.Document(PageSize.LETTER);
try {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
PdfWriter pdfWriter = PdfWriter.getInstance(document, bos);
document.open();
TagProcessorFactory tagProcessorFactory = Tags.getHtmlTagProcessorFactory();
tagProcessorFactory.removeProcessor(HTML.Tag.IMG);
tagProcessorFactory.addProcessor(new ImageTagProcessor(), HTML.Tag.IMG);
CssFilesImpl cssFiles = new CssFilesImpl();
cssFiles.add(XMLWorkerHelper.getInstance().getDefaultCSS());
StyleAttrCSSResolver cssResolver = new StyleAttrCSSResolver(cssFiles);
HtmlPipelineContext hpc = new HtmlPipelineContext(new CssAppliersImpl(new AsianFontProvider(pdfFontBasic, pdfFontBold)));
hpc.setAcceptUnknown(true).autoBookmark(true).setTagFactory(tagProcessorFactory);
HtmlPipeline htmlPipeline = new HtmlPipeline(hpc, new PdfWriterPipeline(document, pdfWriter));
CssResolverPipeline pipeline = new CssResolverPipeline(cssResolver, htmlPipeline);
XMLWorker worker = new XMLWorker(pipeline, true);
Charset charset = StandardCharsets.UTF_8;
XMLParser parser = new XMLParser(true, worker, StandardCharsets.UTF_8);
parser.parse(htmlFile, charset);
pdfWriter.flush();
pdfWriter.close();
return bos.toByteArray();
} finally {
document.close();
}
}
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