【资料图】

简述

最近有个需求需要给pdf加文字水印，于是开始搜索大法，但是发现网络上的代码基本都是将字体文件直接放在jar包里面。个人强迫症发作（手动狗头），想要像poi一样直接加载系统字体，于是研究了一下午pdfbox的源代码，发现FontFileFinder类可以实现这个功能。废话不多说，直接上代码。

引入依赖

    org.apache.pdfbox    pdfbox    org.projectlombok    lombok    provided    jakarta.servlet    jakarta.servlet-api

新增水印配置类

@Data@NoArgsConstructorpublic class PdfWatermarkProperties {    public PdfWatermarkProperties(String content) {        this.content = content;    }    /**     * 文字水印内容     */    private String content = "";    /**     * ttf类型字体文件. 为null则使用默认字体     */    private File fontFile;    private float fontSize = 13;    /**     * cmyk颜色.参数值范围为 0-255     */    private int[] color = {0, 0, 0, 210};    /**     * 透明度     */    private float transparency = 0.3f;    /**     * 倾斜度. 默认30°     */    private double rotate = 0.3;    /**     * 初始添加水印的点位     */    private int x = -10;    private int y = 10;    /**     * 内容区域的宽高.即单个水印范围的大小     */    private int width = 200;    private int height = 200;}

工具类

import org.apache.fontbox.ttf.TTFParser;import org.apache.fontbox.ttf.TrueTypeCollection;import org.apache.fontbox.ttf.TrueTypeFont;import org.apache.fontbox.util.autodetect.FontFileFinder;import org.apache.pdfbox.pdmodel.PDDocument;import org.apache.pdfbox.pdmodel.PDPage;import org.apache.pdfbox.pdmodel.PDPageContentStream;import org.apache.pdfbox.pdmodel.font.PDFont;import org.apache.pdfbox.pdmodel.font.PDType0Font;import org.apache.pdfbox.pdmodel.graphics.state.PDExtendedGraphicsState;import org.apache.pdfbox.util.Matrix;import javax.servlet.http.HttpServletResponse;import java.io.*;import java.net.URI;import java.net.URLEncoder;public class PdfUtil {    private static final String DEFAULT_TTF_FILENAME = "simsun.ttf";    private static final String DEFAULT_TTC_FILENAME = "simsun.ttc";    private static final String DEFAULT_FONT_NAME = "SimSun";    private static final TrueTypeFont DEFAULT_FONT;    static {        DEFAULT_FONT = loadSystemFont();    }    /**     * 加载系统字体,提供默认字体     *     * @return     */    private synchronized static TrueTypeFont loadSystemFont() {        //load 操作系统的默认字体. 宋体        FontFileFinder fontFileFinder = new FontFileFinder();        for (URI uri : fontFileFinder.find()) {            try {                final String filePath = uri.getPath();                if (filePath.endsWith(DEFAULT_TTF_FILENAME)) {                    return new TTFParser(false).parse(filePath);                } else if (filePath.endsWith(DEFAULT_TTC_FILENAME)) {                    TrueTypeCollection trueTypeCollection = new TrueTypeCollection(new FileInputStream(filePath));                    final TrueTypeFont font = trueTypeCollection.getFontByName(DEFAULT_FONT_NAME);                    //复制完之后关闭ttc                    trueTypeCollection.close();                    return font;                }            } catch (Exception e) {                throw new RuntimeException("加载操作系统字体失败", e);            }        }        return null;    }    /**     * 添加文本水印     * * 使用内嵌字体模式，pdf文件大小会增加1MB左右     *     * @param sourceFile 需要加水印的文件     * @param descFile   目标存储路径     * @param props      水印配置     * @throws IOException     */    public static void addTextWatermark(File sourceFile, String descFile, PdfWatermarkProperties props) throws IOException {        // 加载PDF文件        PDDocument document = PDDocument.load(sourceFile);        addTextToDocument(document, props);        document.save(descFile);        document.close();    }    /**     * 添加文本水印     *     * @param inputStream  需要加水印的文件流     * @param outputStream 加水印之后的流。执行完之后会关闭outputStream, 建议使用{@link BufferedOutputStream}     * @param props        水印配置     * @throws IOException     */    public static void addTextWatermark(InputStream inputStream, OutputStream outputStream, PdfWatermarkProperties props) throws IOException {        // 加载PDF文件        PDDocument document = PDDocument.load(inputStream);        addTextToDocument(document, props);        document.save(outputStream);    }    /**     * 处理PDDocument,添加文本水印     *     * @param document     * @param props     * @throws IOException     */    public static void addTextToDocument(PDDocument document, PdfWatermarkProperties props) throws IOException {        document.setAllSecurityToBeRemoved(true);        // 遍历PDF文件，在每一页加上水印        for (PDPage page : document.getPages()) {            PDPageContentStream stream = new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true, true);            // 加载水印字体            if (DEFAULT_FONT == null) {                throw new RuntimeException(String.format("未提供默认字体.请安装字体文件%s或%s", DEFAULT_TTF_FILENAME, DEFAULT_TTC_FILENAME));            }            PDFont font;            if (props.getFontFile() != null) {                font = PDType0Font.load(document, props.getFontFile());            } else {                //当TrueTypeFont为字体集合时, embedSubSet 需要设置为true, 嵌入其子集                font = PDType0Font.load(document, DEFAULT_FONT, true);            }            PDExtendedGraphicsState r = new PDExtendedGraphicsState();            // 设置透明度            r.setNonStrokingAlphaConstant(props.getTransparency());            r.setAlphaSourceFlag(true);            stream.setGraphicsStateParameters(r);            // 设置水印字体颜色            final int[] color = props.getColor();            stream.setNonStrokingColor(color[0], color[1], color[2], color[3]);            stream.beginText();            stream.setFont(font, props.getFontSize());            // 获取PDF页面大小            float pageHeight = page.getMediaBox().getHeight();            float pageWidth = page.getMediaBox().getWidth();            // 根据纸张大小添加水印，30度倾斜            for (int h = props.getY(); h < pageHeight; h = h + props.getHeight()) {                for (int w = props.getX(); w < pageWidth; w = w + props.getWidth()) {                    stream.setTextMatrix(Matrix.getRotateInstance(props.getRotate(), w, h));                    stream.showText(props.getContent());                }            }            // 结束渲染，关闭流            stream.endText();            stream.restoreGraphicsState();            stream.close();        }    }    /**     * 设置pdf文件输出的响应头     *     * @param response web response     * @param fileName 文件名(不含扩展名)     */    public static void setPdfResponseHeader(HttpServletResponse response, String fileName) throws UnsupportedEncodingException {        response.setContentType("application/pdf");        response.setCharacterEncoding("utf-8");        response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8") + ".pdf");    }}

测试

@GetMapping("/t")public void getFile(HttpServletResponse response) throws IOException {    PdfUtil.setPdfResponseHeader(response, "watermark");    final ServletOutputStream out = response.getOutputStream();    PdfUtil.addTextWatermark(new FileInputStream("D:/测试文件.pdf"), out, new PdfWatermarkProperties("测试pdf水印"));}