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POI库的引入与Excel水印处理

1. POI库的引入

在项目中引入必要的库文件，可以通过以下方式实现：

   
    
    
     org.apache.poi
    
    
    
     poi
    
    
    
     4.1.2
    
   
   
    
    
     net.sourceforge.jexcelapi
    
    
    
     jxl
    
    
    
     2.6.11
    
   

2. 生成水印图片的工具类

package org.publiccms.common.excelutil;
import java.awt.AlphaComposite;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.ImageIO;
import java.io.File;
import java.io.IOException;
public class Utilss {
    private static int width = 800;
    private static int height = 1020;
    public static File createWaterMark(String watermark) throws IOException {
        File file = new File("watermark.bmp");
        BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = bi.createGraphics();
        g2.setColor(Color.LIGHT_GRAY);
        g2.setFont(new Font("Serif", Font.ITALIC, 20));
        g2.rotate(Math.toRadians(0), width / 2, height / 2);
        Rectangle2D bounds = g2.getFontRenderContext().getStringBounds(watermark, g2);
        g2.drawString(watermark, (int) (width - bounds.getWidth()) / 2, (int) (height - bounds.getHeight()) / 2);
        ImageIO.write(bi, "bmp", file);
        return file;
    }
    public static File createWaterMark1(String watermarkMessage) throws IOException {
        File file = new File("watermark.bmp");
        BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        for (int i = 0; i < width; i++) {
            for (int j = 0; j < height; j++) {
                bi.setRGB(i, j, 0xFFFFFF);
            }
        }
        Graphics2D g2d = bi.createGraphics();
        g2d.setColor(Color.LIGHT_GRAY);
        g2d.setFont(new Font("Serif", Font.ITALIC, 40));
        g2d.rotate(Math.toRadians(-8));
        for (int i = 1; i < 7; i++) {
            g2d.drawString(" : " + watermarkMessage, 0, 180 * i + 40 * (i + 1));
        }
        g2d.dispose();
        ImageIO.write(bi, "bmp", file);
        return file;
    }
}

3. Excel添加水印工具类

package org.publiccms.common.excelutil;
import myjxl.Workbook;
import myjxl.write.WritableSheet;
import myjxl.write.WritableWorkbook;
public class ExcelUtil {
    public static void addWatermark(String watermarkText) throws Exception {
        File inputStreamFile = new File("in.xls");
        File outputFilePath = new File("out.xls");
        Workbook wb = Workbook.getWorkbook(new FileInputStream(inputStreamFile));
        WritableWorkbook wwb = Workbook.createWorkbook(outputFilePath, wb);
        WritableSheet ws = wwb.getSheet(0);
        File watermarkImage = createWaterMark1(watermarkText);
        byte[] imageData = new byte[watermarkImage.length()];
        FileInputStream fis = new FileInputStream(watermarkImage);
        fis.read(imageData);
        ws.setWatermarkImage(imageData, width, height);
        wwb.write();
        wwb.close();
        fis.close();
    }
}

4. 测试代码

ExcelUtil excelUtil = new ExcelUtil();
excelUtil.addWatermark("水印测试");

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