<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>https://repo.e-iceblue.cn/repository/maven-public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.pdf</artifactId>
        <version>11.9.6</version>
    </dependency>
</dependencies>

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;
import com.spire.pdf.graphics.*;
import com.spire.pdf.graphics.layer.PdfLayer;

import java.awt.*;
import java.awt.geom.Dimension2D;
import java.io.IOException;

public class addLayersToPdf {

    public static void main(String[] args) throws IOException {

        //創(chuàng)建一個(gè)PdfDocument類(lèi)的對(duì)象
        PdfDocument pdf = new PdfDocument();

        //載入PDF文檔
        pdf.loadFromFile("示例.pdf");

        //使用AddLayerWatermark方法來(lái)添加水印圖層
        AddLayerWatermark(pdf);

        //使用AddLayerHeader來(lái)添加頁(yè)眉圖層
        AddLayerHeader(pdf);

        //保存文檔
        pdf.saveToFile("添加圖層.pdf");
        pdf.dispose();
    }

    private static void AddLayerWatermark(PdfDocument doc) {

        //創(chuàng)建一個(gè)名為“水印”的圖層
        PdfLayer layer = doc.getLayers().addLayer("水印");

        //創(chuàng)建字體
        PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("HarmonyOS Sans SC Medium", Font.PLAIN,48),true);

        //指定水印文本
        String watermarkText = "已修改";

        //獲取文本尺寸
        Dimension2D fontSize = font.measureString(watermarkText);

        //計(jì)算偏移量
        float offset1 = (float)(fontSize.getWidth() * Math.sqrt(2) / 4);
        float offset2 = (float)(fontSize.getHeight() * Math.sqrt(2) / 4);

        //獲取頁(yè)面數(shù)
        int pageCount = doc.getPages().getCount();

        //聲明兩個(gè)變量
        PdfPageBase page;
        PdfCanvas canvas;

        //循環(huán)遍歷所有頁(yè)面
        for (int i = 0; i < pageCount; i++) {

            page = doc.getPages().get(i);

            //為圖層創(chuàng)建畫(huà)布
            canvas = layer.createGraphics(page.getCanvas());
            canvas.translateTransform(canvas.getSize().getWidth() / 2 - offset1 - offset2, canvas.getSize().getHeight() / 2 + offset1 - offset2);
            canvas.setTransparency(0.4f);
            canvas.rotateTransform(-45);

            //將文本繪制在圖層畫(huà)布上
            canvas.drawString(watermarkText, font, PdfBrushes.getDarkBlue(), 0, 0);
        }
    }

    private static void AddLayerHeader(PdfDocument doc) {

        //創(chuàng)建名為“頁(yè)眉”的圖層
        PdfLayer layer = doc.getLayers().addLayer("頁(yè)眉");

        //獲取頁(yè)面尺寸
        Dimension2D size = doc.getPages().get(0).getSize();

        //獲取頁(yè)面數(shù)
        int pageCount = doc.getPages().getCount();

        //聲明兩個(gè)變量
        PdfPageBase page;
        PdfCanvas canvas;

        //循環(huán)遍歷所有頁(yè)面
        for (int i = 0; i < pageCount; i++) {

            //在圖層上繪制圖片
            PdfImage pdfImage = PdfImage.fromFile("頁(yè)眉.jpg");
            page = doc.getPages().get(i);
            float width = pdfImage.getWidth();
            float height = pdfImage.getHeight();
            float x = (float) size.getWidth()/2 - width/2;
            float y = 30;
            canvas = layer.createGraphics(page.getCanvas());
            canvas.drawImage(pdfImage, x, y, width, height);

            //在圖層上畫(huà)一條線(xiàn)
            PdfPen pen = new PdfPen(PdfBrushes.getDarkGray(), 2f);
            canvas.drawLine(pen, x, y + height + 5, size.getWidth() - x, y + height + 2);
        }
    }
}

import com.spire.pdf.FileFormat;
import com.spire.pdf.PdfDocument;
import com.spire.pdf.graphics.layer.PdfVisibility;

public class setLayerVisibility {
    public static void main(String[] args) {

        //創(chuàng)建一個(gè)PdfDocument類(lèi)的對(duì)象
        PdfDocument pdf = new PdfDocument();

        //載入PDF文檔
        pdf.loadFromFile("添加圖層.pdf");

        //將第一個(gè)圖層的可見(jiàn)性設(shè)置為Off
        pdf.getLayers().get(0).setVisibility(PdfVisibility.Off);

        //保存文檔
        pdf.saveToFile("隱藏圖層.pdf", FileFormat.PDF);
        pdf.dispose();
    }
}

import com.spire.pdf.PdfDocument;

public class deleteLayers {

    public static void main(String[] args) {

        //創(chuàng)建一個(gè)PdfDocument類(lèi)的對(duì)象
        PdfDocument pdf = new PdfDocument();

        //載入PDF文檔
        pdf.loadFromFile("添加圖層.pdf");

        //通過(guò)名稱(chēng)刪除指定圖層
        pdf.getLayers().removeLayer("頁(yè)眉");

        //保存文檔
        pdf.saveToFile("刪除圖層.pdf");
        pdf.close();
    }
}