java将html转换为pdf，支持中文。

这段时间接到报表导出pdf功能的测试，要求兼容ie5，所以前端无法兼容，就由后端来处理。在开发过程中查找了大量的资料，最终确认用html2pdf工具来进行转换，开发很顺利，但是测试过程中发现当报表列数过多的时显示不全，后来想到将列数过多的报表先使用html2image工具将其转为图片后在插入导pdf中，来实现pdf的导出，但是现在有个问题就是转图片后的清晰度不是很理想。如果大家有更好的方法请指导一下。

需要导入中文字体：

相关jar的引入

	 <dependency>
        <groupId>com.itextpdf</groupId>
        <artifactId>itextpdf</artifactId>
        <version>5.5.11</version>
      </dependency>
      <dependency>
        <groupId>com.itextpdf</groupId>
        <artifactId>itext-asian</artifactId>
        <version>5.2.0</version>
      </dependency>
      <dependency>
        <groupId>gui.ava</groupId>
        <artifactId>html2image</artifactId>
        <version>0.9</version>
      </dependency>
      <dependency>
        <groupId>com.itextpdf</groupId>
        <artifactId>html2pdf</artifactId>
        <version>2.1.0</version>
      </dependency>

直接上代码：列数少的报表直接转pdf

 public static void exportToPdf(String name, String htmlText,
                                   HttpServletRequest request, HttpServletResponse response) {
        try {

            // 设置文件名称
            name = name + "_" + DateUtils.getNow("yyyyMMddHHmmss");

            // 设置文件名字编码集
            String fileName =  URLEncoder.encode(name,"UTF8") + ".pdf";
            ConverterProperties props = new ConverterProperties();
            FontProvider fp = new FontProvider();
            fp.addStandardPdfFonts();
            String resources = ReportHelper.class.getResource("/font").getPath();
            fp.addDirectory(resources);
            props.setFontProvider(fp);
            OutputStream os = response.getOutputStream();
            List<IElement> elements = HtmlConverter.convertToElements(htmlText, props);
            PdfDocument pdf = new PdfDocument(new PdfWriter(os));
            Document document = new Document(pdf, PageSize.A4, true);
            for (IElement element : elements) {
                    document.add((IBlockElement) element);
            }

            // 响应数据
            response.setContentType("application/pdf; charset=utf-8");
            response.setHeader("Content-Disposition", String.format("attachment; filename=%s", fileName));
            response.setHeader("Set-Cookie", "fileDownload=true; path=/");
            document.close();
            os.flush();
            os.close();
        } catch (IOException e) {
            throw new Exception("PDF导出失败", e.getMessage());
        }
    }

报表列数过多先将其转为图片进行缩小后插入pdf：

public static void exportToPdfImage(String name, String htmlText,
                                        HttpServletRequest request, HttpServletResponse response) {
        String fileName = "";
        try {
            // 设置文件名称
            name = name + "_" + DateUtils.getNow("yyyyMMddHHmmss");
            // 设置文件名字编码集
            fileName = URLEncoder.encode(name, "UTF8") + ".pdf";
            OutputStream os = response.getOutputStream();
            Document document = new Document(PageSize.A4);
            // html转成图片
            HtmlImageGenerator imageGenerator = new HtmlImageGenerator();
            imageGenerator.loadHtml(htmlText);
            imageGenerator.getBufferedImage();
            imageGenerator.saveAsImage(fileName + ".png");
            // 响应数据
            response.setContentType("application/pdf; charset=utf-8");
            response.setHeader("Content-Disposition", String.format("attachment; filename=%s", fileName));
            response.setHeader("Set-Cookie", "fileDownload=true; path=/");
            PdfWriter.getInstance(document, os);
            document.open();
            Image image = Image.getInstance(fileName + ".png");
            float imageHeight = image.getScaledHeight();
            float imageWidth = image.getScaledWidth();
            int i = 0;
            while (imageHeight > 800 || imageWidth > 500) {
                image.scalePercent(100 - i);
                i++;
                imageHeight = image.getScaledHeight();
                imageWidth = image.getScaledWidth();
            }
            image.setAlignment(Image.MIDDLE);
            document.add(image);
            document.close();
            os.flush();
            os.close();
        } catch (Exception e) {
            throw new Exception("PDF导出失败", e.getMessage());
        } finally {
            // 获取文件进行删除
            File file = new File(fileName + ".png");
            boolean isok = file.exists();
            if (isok) {
                file.delete();
            }
        }
    }

本文地址：https://blog.csdn.net/weixin_44673689/article/details/111865994