java后台生成pdf报告

该文章的为传递一整套html内容，后台转为pdf的方法，有一个小问题是（html里写的图片无法生成出来。。不知道为啥）

1、先引入jar包

	<!-- todo html转pdf-->
		<dependency>
			<groupId>com.itextpdf.tool</groupId>
			<artifactId>xmlworker</artifactId>
			<version>5.5.1</version>
		</dependency>
		<!-- 支持中文 -->
		<dependency>
			<groupId>com.itextpdf</groupId>
			<artifactId>itext-asian</artifactId>
			<version>5.2.0</version>
		</dependency>
		<!-- 支持css样式渲染 -->
		<dependency>
			<groupId>org.xhtmlrenderer</groupId>
			<artifactId>flying-saucer-pdf-itext5</artifactId>
			<version>9.0.3</version>
		</dependency>
		<!-- todo html转pdf-->

2、编写生成pdf的语句

public static void htmlTopdf(String html, File file) throws Exception {
		try {
			// step 1
			Document document = new Document();
			BaseFont bfChinese;
			bfChinese = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", false);
			MyFontProvider myFontProvider = new MyFontProvider(BaseColor.BLACK, "", "", false, false, 8, 1, bfChinese);
			// step 2
			PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(file));
			writer.setStrictImageSequence(true);
			// step 3
			document.open();
// todo 因为html无法生成图片，最后想了一个折中的办法，在pdf里生成，这个是直接通过网络路径转的
			String url=ImageBase64("https://img-blog.csdnimg.cn/24828250aeca4b38b7d2d1847ccc4df4.png");
			byte [] byteArray = Base64.getDecoder().decode(url);
			Image image2 = Image.getInstance(byteArray);
			document.add(image2);
			float currentWidth = image2.getWidth();
			float currentHeight = image2.getHeight();
			image2.scalePercent(50);
			float newWidth = image2.getWidth();
			float newHeight = image2.getHeight();
// todo --------------------也可能写错了，哈哈这段代码是从历史记录里翻出来的。不确定是不是写的有问题，懒得再找。不对的话，可以搜一下。可以肯定能实现图片这个功能
			final TagProcessorFactory tagProcessorFactory = Tags.getHtmlTagProcessorFactory();
			tagProcessorFactory.removeProcessor(HTML.Tag.IMG);

			final CssFilesImpl cssFiles = new CssFilesImpl();
			cssFiles.add(XMLWorkerHelper.getInstance().getDefaultCSS());
			final StyleAttrCSSResolver cssResolver = new StyleAttrCSSResolver(cssFiles);
			final HtmlPipelineContext hpc = new HtmlPipelineContext(new CssAppliersImpl(myFontProvider));
			hpc.setAcceptUnknown(true).autoBookmark(true).setTagFactory(tagProcessorFactory);
			final HtmlPipeline htmlPipeline = new HtmlPipeline(hpc, new PdfWriterPipeline(document, writer));
			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);

			ByteArrayInputStream bais = new ByteArrayInputStream(html.getBytes(StandardCharsets.UTF_8));
			xmlParser.parse(bais, charset);

			// step 5
			document.close();
			bais.close();
		} catch (Exception e) {
			throw new Exception(e);
		}
	}

3、网络图片转地址

rivate static String ImageBase64(String imgUrl) {
        URL url = null;
        InputStream is = null;
        ByteArrayOutputStream outStream = null;
        HttpURLConnection httpUrl = null;
        try{
            url = new URL(imgUrl);
            httpUrl = (HttpURLConnection) url.openConnection();
            httpUrl.connect();
            httpUrl.getInputStream();
            is = httpUrl.getInputStream();
 
            outStream = new ByteArrayOutputStream();
            //创建一个Buffer字符串
            byte[] buffer = new byte[1024];
            //每次读取的字符串长度，如果为-1，代表全部读取完毕
            int len = 0;
            //使用一个输入流从buffer里把数据读取出来
            while( (len=is.read(buffer)) != -1 ){
                //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
                outStream.write(buffer, 0, len);
            }
            // 对字节数组Base64编码
            // java11与后面版本用这个
            return new Base64Util().encode(outStream.toByteArray());
            // java11之前用这个
            return new BASE64Encoder().encode(outStream.toByteArray());
        }catch (Exception e) {
            e.printStackTrace();
        }
        finally{
            if(is != null)
            {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(outStream != null)
            {
                try {
                    outStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(httpUrl != null)
            {
                httpUrl.disconnect();
            }
        }
        return imgUrl;
    }

4、调用传值方法将要生成pdf的图片和内容传给2方法。对html语句要求比较严格，但是如果那个标签的结束符未写，是无法生成的。

public static void main(String[] args) {
		String content =
			"<html>\n" +
					"<head>\n" +
					"    <meta charset=\"UTF-8\"></meta>\n" +
					"    <meta name=\"viewport\" content=\"width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0\"></meta>\n" +
					"    <title>ddsa</title>\n" +
					"    <style>\n" +
					"</style>\n" +
					"</head>\n" +
					"<body style=\"width=1800px;\">\n" +

					"<div>123123123</div></body>\n" +
					"</html>";
		String url="d:/ss.pdf";
		File file = new File(url);


		try {
			htmlTopdf(content, file);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

最终样式：（图片太大我给注释了）