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
<!-- pdfbox-->
<dependency>
<groupId>org.apache.pdfbox</groupId>
<artifactId>pdfbox</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<scope>provided</scope>
</dependency>
<!-- 提供 HttpServlet 相关类 -->
<dependency>
<groupId>jakarta.servlet</groupId>
<artifactId>jakarta.servlet-api</artifactId>
</dependency>
新增水印配置类
@Data
@NoArgsConstructor
public 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"));
}