Java利用Apache PDFBox库为PDF添加文本水印：附详细代码示例

要在Java中为PDF添加水印，您可以使用Apache PDFBox库。以下是一个简单的示例代码，用于向PDF文件添加文本水印： ```java import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import javax.imageio.ImageIO; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.pdmodel.PDPage; import org.apache.pdfbox.pdmodel.PDPageContentStream; import org.apache.pdfbox.pdmodel.fontsize.PDFontSizeData; import org.apache.pdfbox.pdmodel.fontsize.PDType1Font; public class AddWatermarkToPDF { public static void main(String[] args) { try { // Load PDF document PDDocument document = PDDocument.load(new File("input.pdf")); // Create a watermark image with text and font size BufferedImage watermarkImage = createWatermarkImage("Watermark", 20); // Get the first page of the document PDPage page = document.getPage(0); // Create a content stream for the watermark to be added to the page PDPageContentStream contentStream = new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true); contentStream.beginText(); contentStream.setFont(PDType1Font.HELVETICA_BOLD, 12); // Set the font and font size for the watermark text contentStream.newLineAtOffset(50, 50); // Position the watermark at the top-left corner of the page contentStream.showText(watermarkImage); // Add the watermark text to the content stream contentStream.endText(); contentStream.close(); // Close the content stream after adding the watermark // Save the modified PDF document document.save("output.pdf"); document.close(); } catch (IOException e) { e.printStackTrace(); } } private static BufferedImage createWatermarkImage(String text, int fontSize) { BufferedImage watermarkImage = new BufferedImage(100, 50, BufferedImage.TYPE_INT_RGB); // Create a watermark image with a placeholder text string and font size Graphics2D graphics = watermarkImage.createGraphics(); // Create a graphics context for the watermark image graphics.setColor(Color.BLACK); // Set the color of the watermark text to black graphics.setFont(new Font("Arial", Font.PLAIN, fontSize)); // Set the font for the watermark text to Arial with a given font size graphics.drawString(text, 50, 50); // Draw the placeholder text string at the top-left corner of the watermark image with a given position and size graphics.dispose(); // Dispose of the graphics context after drawing the watermark text onto the image return watermarkImage; } } ``` 在上面的代码中，我们首先加载了一个PDF文件，然后使用`createWatermarkImage()`方法创建一个带有文本的水印图像。该方法将使用给定的文本字符串、字体和字体大小来创建图像。接下来，我们获取PDF文档中的第一页，并使用`PDPageContentStream`类创建一个内容流，以便将水印添加到页面上。在内容流中，我们使用字体和字体大小设置水印文本的样式，并将水印文本添加到页面上。我们将修改后的PDF文档保存到磁盘上。您需要将代码中的文件路径和文件名替换为您自己的文件路径和文件名。 ######[AI写代码神器 | 875点数解答 | 2024-02-22 18:17:43]