Java使用pdfbox实现给pdf文件加图片水印
目录
引入依赖
代码
效果
引入依赖<dependency>
<groupId>org.apache.pdfbox</groupId>
<artifactId>pdfbox</artifactId>
<version>2.0.27</version>
</dependency>
代码
调节参数：图片宽高，旋转角度，几行几列 等等
package sjp.demo.workutils.utils;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.graphics.blend.BlendMode;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.pdmodel.graphics.state.PDExtendedGraphicsState;
import org.apache.pdfbox.util.Matrix;
import java.io.File;
import java.io.IOException;
public class PdfUtils {
public static void main(String[] args) throws IOException {
String file = "D:\\workspaces\\demo\\sjp-work-utils\\src\\main\\resources\\pdf\\阿拉丁统计平台SDK接入指南.pdf";
String imgPath = "D:\\workspaces\\demo\\sjp-work-utils\\src\\main\\resources\\imgs\\logo.png";
addImgWatermark(file, imgPath);
}
public static void addImgWatermark(String filePath, String imgPath) throws IOException {
String name = filePath.substring(filePath.lastIndexOf(File.separator), filePath.lastIndexOf(".pdf"));
String folder = filePath.substring(0, filePath.lastIndexOf(File.separator));
File file = new File(filePath);
try (PDDocument doc = PDDocument.load(file)) {
PDImageXObject pdImage = PDImageXObject.createFromFile(imgPath, doc);
WatermarkOptions options = new WatermarkOptions()
.size(120, 60)
.padding(20)
.layout(4, 3)
// 建议0-90度
.rotate(30);
for (PDPage page : doc.getPages()) {
addImgWatermark(doc, page, pdImage, options);
}
doc.save(folder + File.separator + name + "_WaterMark.pdf");
}
}
private static void addImgWatermark(PDDocument doc, PDPage page, PDImageXObject pdImage, WatermarkOptions options) throws IOException {
try (
PDPageContentStream cs = new PDPageContentStream(doc, page, PDPageContentStream.AppendMode.APPEND, true, true)
) {
float width = page.getMediaBox().getWidth();
float height = page.getMediaBox().getHeight();
// System.out.println("width=" + width + ",height=" + height);
//有一些pdf页面是有角度翻转的，修正一下
int rotation = page.getRotation();
// System.out.println("page.getRotation()=" + rotation);
switch (rotation) {
case 90:
width = page.getMediaBox().getHeight();
height = page.getMediaBox().getWidth();
cs.transform(Matrix.getRotateInstance(Math.toRadians(90), height, 0));
break;
case 180:
cs.transform(Matrix.getRotateInstance(Math.toRadians(180), width, height));
break;
case 270:
width = page.getMediaBox().getHeight();
height = page.getMediaBox().getWidth();
cs.transform(Matrix.getRotateInstance(Math.toRadians(270), 0, width));
break;
default:
break;
}
PDExtendedGraphicsState gs = new PDExtendedGraphicsState();
gs.setNonStrokingAlphaConstant(0.2f);// 设置透明度
gs.setAlphaSourceFlag(true);
gs.setBlendMode(BlendMode.NORMAL);
cs.setGraphicsStateParameters(gs);
int row = options.row;
int column = options.column;
float imgWidth = options.width;
float imgHeight = options.height;
float padding = options.padding;
int degree = options.degree;
// 计算获得每个单元格的宽高
float cellWidth = (width - padding * 2) / column;
float cellHeight = (height - padding * 2) / row;
// System.out.println("cellWidth=" + cellWidth + ",cellHeight=" + cellHeight);
// 偏移量，如果单元格宽高大于图片宽高，这可以使图片居中
float xOffset = padding + (cellWidth - imgWidth) / 2;
float yOffset = padding + (cellHeight - imgHeight) / 2;
float x;
float y;
for (int i = 0; i < row; i++) {
y = i * cellHeight + yOffset;
for (int j = 0; j < column; j++) {
x = j * cellWidth + xOffset;
// 旋转导致的x位置修正
x += Math.sin(Math.toRadians(degree)) * imgHeight;
// System.out.println((int) x + "," + (int) y);
Matrix matrix = new Matrix();
// 先移位
matrix.translate(x, y);
// 旋转
matrix.rotate(Math.toRadians(degree));
// 修改尺寸（必须在旋转后面，否则会变形）
matrix.scale(imgWidth, imgHeight);
// 画图
cs.drawImage(pdImage, matrix);
}
}
}
}
static class WatermarkOptions {
/**
* 边距
*/
float padding = 20;
/**
* 图片宽度
*/
float width;
/**
* 图片高度
*/
float height;
/**
* 旋转角度
*/
int degree = 0;
/**
* 行数
*/
int row = 1;
/**
* 列数
*/
int column = 1;
public WatermarkOptions() {
}
public WatermarkOptions padding(int p) {
if (p < 10) {
throw new IllegalArgumentException("边距不能小于0");
}
this.padding = p;
return this;
}
public WatermarkOptions layout(int row, int column) {
if (row <= 0 || column <= 0) {
throw new IllegalArgumentException("行数或列数必须大于0");
}
this.row = row;
this.column = column;
return this;
}
public WatermarkOptions size(float width, float height) {
this.width = width;
this.height = height;
return this;
}
public WatermarkOptions rotate(int degree) {
this.degree = degree;
return this;
}
}
}
效果
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