java为PDF添加水印，文字水印和图片水印
一个需求，下载pdf、word、excel文件时要带有水印，要求铺满。先分开，先介绍为PDF文件添加文字水印和图片水印。
所需jar包：itext-2.0.1.jar。（itextpdf-5.5.8.jar，这个类似）
jar包可在这里下载：/
创建水印图片的类
import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.RenderingHints;import java.awt.Transparency;import java.awt.image.BufferedImage;import java.io.File;import javax.imageio.ImageIO;public class ImageUtil {/*** 生成背景透明的文字水印图片，文字位于中央，且倾斜* @param content 水印文字* @return*/public static BufferedImage createWaterMark(String content) {//生成图片宽度int width = 250;//生成图片高度int heigth = 160;//获取bufferedImage对象BufferedImage image = new BufferedImage(width, heigth, BufferedImage.TYPE_INT_RGB);//得到画笔对象Graphics2D g2d = image.createGraphics();//使得背景透明image = g2d.getDeviceConfiguration().createCompatibleImage(width, heigth, Transparency.TRANSLUCENT);g2d.dispose();g2d = image.createGraphics();//设置对线段的锯齿状边缘处理g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);//设置水印旋转，倾斜度g2d.rotate(-0.5, (double) image.getWidth()/2, (double) image.getHeight()/2);//设置颜色，这是黑色，第4个参数是透明度g2d.setColor(new Color(0, 0, 0, 20));//设置字体Font font = new Font("宋体", Font.ROMAN_BASELINE, 22);g2d.setFont(font);float fontSize = font.getSize();//计算绘图偏移x、y，使得使得水印文字在图片中居中float x = 0.5f * fontSize;float y = 0.5f * heigth + x;//取绘制的字串宽度、高度中间点进行偏移，使得文字在图片坐标中居中g2d.drawString(content, x, y);//释放资源g2d.dispose();return image;}public static void main(String[] args) throws Exception {BufferedImage bi = createWaterMark("水印图片 -12-32");ImageIO.write(bi, "png", new File("E:\\waterMark.png")); //写入文件}}
效果图
PDF添加图片水印的类
import java.io.FileOutputStream;import com.lowagie.text.Image;import com.lowagie.text.pdf.PdfContentByte;import com.lowagie.text.pdf.PdfGState;import com.lowagie.text.pdf.PdfReader;import com.lowagie.text.pdf.PdfStamper;public class PDFUtil {/*** pdf文件添加图片水印* itext-2.0.1.jar* @param srcPath 输入的文件路径* @param destPath 输出的文件路径* @param imagePath 水印图片的路径* @throws Exception*/public static void addPDFImageWaterMark(String srcPath, String destPath, String imagePath) throws Exception {PdfReader reader = new PdfReader(srcPath);PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(destPath));//加载图片Image image = Image.getInstance(imagePath);PdfGState gs = new PdfGState();//gs.setFillOpacity(0.2f);//图片水印透明度//gs.setStrokeOpacity(0.4f);//设置笔触字体不透明度PdfContentByte content = null;int total = reader.getNumberOfPages();//pdf文件页数for (int i=0; i<total; i++) {float x = reader.getPageSize(i+1).width();//页宽度float y = reader.getPageSize(i+1).height();//页高度content = stamper.getOverContent(i+1);content.setGState(gs);content.beginText();//开始写入//每页7行，一行3个for (int j=0; j<3; j++) {for (int k=0; k<7; k++) {//setAbsolutePosition 方法的参数（输出水印X轴位置，Y轴位置）image.setAbsolutePosition(x/3*j-30, y/7*k-20);content.addImage(image);}}content.endText();//结束写入}//关闭流stamper.close();reader.close();}public static void main(String[] args) throws Exception {addPDFImageWaterMark("E:\\测试.pdf", "E:\\测试水印img.pdf", "E:\\waterMark.png");}}
效果图
PDF添加文字水印的类
与图片水印的类似，稍微改动
import java.io.FileOutputStream;import com.lowagie.text.Element;import com.lowagie.text.Image;import com.lowagie.text.pdf.BaseFont;import com.lowagie.text.pdf.PdfContentByte;import com.lowagie.text.pdf.PdfGState;import com.lowagie.text.pdf.PdfReader;import com.lowagie.text.pdf.PdfStamper;public class PDFUtil {/*** pdf文件添加文字水印* @param srcPath 输入的文件路径* @param destPath 输出的文件路径* @param word 水印文字* @throws Exception*/public static void addPDFWaterMark(String srcPath, String destPath, String word) throws Exception {PdfReader reader = new PdfReader(srcPath);PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(destPath));//使用系统字体String prefixFont = null;String os = System.getProperties().getProperty("os.name");if (os.startsWith("win") || os.startsWith("Win")) {prefixFont = "C:\\Windows\\Fonts\\SIMSUN.TTC,1";} else {prefixFont = "/usr/share/fonts/chinese/TrueType/uming.ttf";}//创建字体，第一个参数是字体路径BaseFont base = BaseFont.createFont(prefixFont, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);//BaseFont base = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", BaseFont.EMBEDDED);PdfGState gs = new PdfGState();gs.setFillOpacity(0.2f);//图片水印透明度//gs.setStrokeOpacity(0.4f);//设置笔触字体不透明度PdfContentByte content = null;int total = reader.getNumberOfPages();//pdf文件页数for (int i=0; i<total; i++) {float x = reader.getPageSize(i+1).width();//页宽度float y = reader.getPageSize(i+1).height();//页高度content = stamper.getOverContent(i+1);content.setGState(gs);content.beginText();//开始写入content.setFontAndSize(base, 20);//字体大小//每页7行，一行3个for (int j=0; j<3; j++) {for (int k=0; k<7; k++) {//showTextAligned 方法的参数（文字对齐方式，位置内容，输出水印X轴位置，Y轴位置，旋转角度）content.showTextAligned(Element.ALIGN_CENTER, word, x/3*j+90, y/7*k, 25);}}content.endText();//结束写入}//关闭流stamper.close();reader.close();}public static void main(String[] args) throws Exception {addPDFWaterMark("E:\\测试.pdf", "E:\\测试水印.pdf", "水印测试 -12-32");}}
效果图
若用的是itextpdf-5.5.8.jar，则需改动以下两处
float x = reader.getPageSize(i+1).getWidth(); //页宽度
float y = reader.getPageSize(i+1).getHeight(); //页高度
