flying-saucer + iText + Freemarker实现pdf的导出，支持中文、css以及图片

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

　　　1508383793597.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；

参考

　　获取java项目根目录

　　freemarker+Flying sauser +Itext 整合生成PDF