前言
项目中有个需求，需要将合同内容导出成pdf。上网查阅到了 iText ， iText 是一个生成PDF文档的开源Java库，能够动态的从XML或者数据库生成PDF，同时还可以对文档进行加密，权限控制，并且还支持Java/C#等，但是iText本身提供的HTML解析器还是不够强大，许多HTML标签和属性无法识别，更悲催的是简单的CSS它不认识，排版调整样式让人头大。那么有没有什么方式能够支持css呢，又查阅到了 flying-saucer， flying-saucer也是导出PDF的一种解决方案，并且是基于iText的开源API，并且实现了CSS解析器，能够很好的支持CSS2.1，以及少量的CSS。最终解决方案定为： flying-saucer + iText + Freemarker。
具体实现
流程如下
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.yzb.lee</groupId> <artifactId>itextpdf</artifactId> <packaging>war</packaging> <version>0.0.1-SNAPSHOT</version> <name>itextpdf Maven Webapp</name> <url>http://maven.apache.org</url> <dependencies> <dependency> <groupId>org.freemarker</groupId> <artifactId>freemarker</artifactId> <version>2.3.20</version> </dependency> <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> <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 --> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.4</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> </dependencies> <build> <finalName>itextpdf</finalName> </build> </project>
1、html内容的输出
模版文件fileTemplate.html
<html> <head> <title>${title}</title> <!-- link链接应该写文件服务器地址， 出于演示，这里用的localhost --> <link type="text/css" rel="stylesheet" href="http://localhost:8080/itextpdf/css/pdf.css" /> <style> @page { size: 8.5in 11in; @ bottom-center { content : "page " counter( page ) " of " counter( pages ); } } </style> </head> <body> <h1>Just a blank page.</h1> <div style="page-break-before: always;"> <div align="center"> <h1>${title}</h1> <!-- src链接应该写文件服务器地址， 出于演示，这里用的localhost --> <img alt="加载中..." src="http://localhost:8080/itextpdf/images/aloner.jpg" /> </div> <table> <tr> <td><b>Name</b></td> <td><b>Age</b></td> <td><b>Sex</b></td> </tr> <#list userList as user> <tr> <td>${user.name}</td> <td>${user.age}</td> <td><#if user.sex = 1> male <#else> female </#if></td> </tr> </#list> </table> </div> <div> <a href="https://www.baidu.com/" target="_blank">百度</a> </div> </body> </html>
动态数据的获取
public Map<String, Object> getContent() throws IOException { // 从数据库中获取数据， 出于演示目的， 这里数据不从数据库获取， 而是直接写死 Map<String, Object> variables = new HashMap<String, Object>(3); List<User> userList = new ArrayList<User>(); User tom = new User("Tom", 19, 1); User amy = new User("Amy", 28, 0); User leo = new User("Leo", 23, 1); userList.add(tom); userList.add(amy); userList.add(leo); variables.put("title", "用户列表"); variables.put("userList", userList); return variables; }
动态数据的绑定，html内容的输出
/** * Generate html string. * * @param template * the name of freemarker teamlate. * @param variables * the data of teamlate. * @return htmlStr * @throws Exception */ public static String generate(String template, Map<String, Object> variables) throws Exception { Configuration config = FreemarkerConfiguration.getConfiguation(); Template tp = config.getTemplate(template); StringWriter stringWriter = new StringWriter(); BufferedWriter writer = new BufferedWriter(stringWriter); tp.setEncoding("UTF-8"); tp.process(variables, writer); String htmlStr = stringWriter.toString(); writer.flush(); writer.close(); return htmlStr; }
2、pdf的导出
private void generatePdf(String htmlStr, OutputStream out) throws IOException, DocumentException { //final ServletContext servletContext = getServletContext(); Document document = new Document(PageSize.A4, 30, 30, 30, 30); document.setMargins(30, 30, 30, 30); PdfWriter writer = PdfWriter.getInstance(document, out); document.open(); // html内容解析 HtmlPipelineContext htmlContext = new HtmlPipelineContext( new CssAppliersImpl(new XMLWorkerFontProvider() { @Override public Font getFont(String fontname, String encoding, float size, final int style) { Font font = null; if (fontname == null) { //字体 String fontCn = getChineseFont(); BaseFont bf; try { //注意这里有一个,1 bf = BaseFont.createFont(fontCn+",1", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED); font = new Font(bf, size, style); } catch (DocumentException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } return font; } })) { @Override public HtmlPipelineContext clone() throws CloneNotSupportedException { HtmlPipelineContext context = super.clone(); try { ImageProvider imageProvider = this.getImageProvider(); context.setImageProvider(imageProvider); } catch (NoImageProviderException e) { } return context; } }; // 图片解析 htmlContext.setImageProvider(new AbstractImageProvider() { // String rootPath = servletContext.getRealPath("/"); @Override public String getImageRootPath() { return ""; } @Override public Image retrieve(String src) { if (StringUtils.isEmpty(src)) { return null; } try { // String imageFilePath = new File(rootPath, src).toURI().toString(); Image image = Image.getInstance(src); image.setAbsolutePosition(400, 400); if (image != null) { store(src, image); return image; } } catch (Throwable e) { e.printStackTrace(); } return super.retrieve(src); } }); htmlContext.setAcceptUnknown(true).autoBookmark(true) .setTagFactory(Tags.getHtmlTagProcessorFactory()); // css解析 CSSResolver cssResolver = XMLWorkerHelper.getInstance() .getDefaultCssResolver(true); cssResolver.setFileRetrieve(new FileRetrieve() { @Override public void processFromStream(InputStream in, ReadingProcessor processor) throws IOException { try (InputStreamReader reader = new InputStreamReader(in, CHARSET_NAME)) { int i = -1; while (-1 != (i = reader.read())) { processor.process(i); } } catch (Throwable e) { } } // 解析href @Override public void processFromHref(String href, ReadingProcessor processor) throws IOException { // InputStream is = servletContext.getResourceAsStream(href); URL url = new URL(href); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(5 * 1000); InputStream is = conn.getInputStream(); try (InputStreamReader reader = new InputStreamReader(is, CHARSET_NAME)) { int i = -1; while (-1 != (i = reader.read())) { processor.process(i); } } catch (Throwable e) { e.printStackTrace(); } } }); HtmlPipeline htmlPipeline = new HtmlPipeline(htmlContext, new PdfWriterPipeline(document, writer)); Pipeline<?> pipeline = new CssResolverPipeline(cssResolver, htmlPipeline); XMLWorker worker = null; worker = new XMLWorker(pipeline, true); XMLParser parser = new XMLParser(true, worker, Charset.forName(CHARSET_NAME)); try (InputStream inputStream = new ByteArrayInputStream( htmlStr.getBytes())) { parser.parse(inputStream, Charset.forName(CHARSET_NAME)); } document.close(); }
3、生成的pdf
注意点
1、博客中的代码不是一个完整工程，只依赖博客中的代码是运行不起来的；
2、文件路径的获取，本地文件与远程文件的获取是有区别的， 另外本地文件的获取又存在多种方式；
3、完整工程地址：itextpdf，仔细阅读readme.txt， 工程中存在多个版本， 而本博客对应的是版本4；
4、推荐将SIMSUN.TTC放到工程中， 这就不依赖操作系统了， 可移植性更强；