iText的showTextAligned方法

java使用itext的showTextAligned方法给pdf添加文字水印(watermark)

 

2013-07-22 17:39:59   来源：   评论：0 点击：3582

 

java的开源pdf库-Itext可以给pdf添加水印,主要是使用showTextAligned这个方法.ShowTextAligned方法可以设置输出水印的文本和水印文本的旋转角度,ShowTextAligned方法具体的参数说明如下:

public void ShowTextAligned(int alignment, String text, float x,float y, float rotation)

参数	参数说明：
alignment	左、右、居中(ALIGN_CENTER, ALIGN_RIGHT or ALIGN_LEFT)
text	要输出的文本
x	文本输入的X坐标
y	文本输入的Y坐标
rotation	文本的旋转角度

将itext-5.4.2.zip压缩包解压缩后得到7个文件：itextpdf-5.4.2.jar(核心组件)、itextpdf-5.4.2-javadoc.jar(API文档)、itextpdf-5.4.2-sources.jar(源代码)、itext-xtra-5.4.2.jar、itext-xtra-5.4.2-javadoc.jar、itext-xtra-5.4.2-sources.jar ,如果是输出中文pdf,需要用到itext-asian.jar这个jar包,这个jar包在extrajars-2.3.zip中,下载地址:请点这里

private static void addWatermark(PdfStamper pdfStamper
, String waterMarkName) {
PdfContentByte content = null;
BaseFont base = null;
Rectangle pageRect = null;
PdfGState gs = new PdfGState();
try { // 设置字体
base = BaseFont.createFont("STSongStd-Light",
"UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);
} catch (DocumentException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (base == null || pdfStamper == null) { return; }
// 设置透明度为0.4
gs.setFillOpacity(0.4f);
gs.setStrokeOpacity(0.4f);
int toPage = pdfStamper.getReader().getNumberOfPages();
for (int i = 1; i <= toPage; i++) {
pageRect = pdfStamper.getReader(). getPageSizeWithRotation(i);
// 计算水印X,Y坐标
float x = pageRect.getWidth() / 2;
float y = pageRect.getHeight() / 2;
//获得PDF最顶层
content = pdfStamper.getOverContent(i);
content.saveState();
// set Transparency
content.setGState(gs);
content.beginText();
content.setColorFill(BaseColor.GRAY);
content.setFontAndSize(base, 60);
// 水印文字成45度角倾斜
content.showTextAligned(Element.ALIGN_CENTER ,
waterMarkName, x, y, 45); content.endText(); }
} catch (Exception ex) {
ex.printStackTrace();
}
finally {
content = null;
base = null;
pageRect = null;
}
}

java使用itext的showTextAligned方法给pdf添加文字水印的完整代码如下:

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package com.pdf;     import java.io.FileOutputStream; import java.io.IOException;    import com.itextpdf.text.BaseColor; import com.itextpdf.text.Chunk; import com.itextpdf.text.Document; import com.itextpdf.text.DocumentException; import com.itextpdf.text.Element; import com.itextpdf.text.Font; import com.itextpdf.text.PageSize; import com.itextpdf.text.Paragraph; import com.itextpdf.text.Rectangle; import com.itextpdf.text.pdf.BaseFont; import com.itextpdf.text.pdf.PdfContentByte; import com.itextpdf.text.pdf.PdfGState; import com.itextpdf.text.pdf.PdfPCell; import com.itextpdf.text.pdf.PdfPTable; import com.itextpdf.text.pdf.PdfReader; import com.itextpdf.text.pdf.PdfStamper; import com.itextpdf.text.pdf.PdfWriter;    public class ItextHelloword {         public static void main(String[] args) throws Exception {         String pdfFilePath = "f:/itext-demo.pdf";          PdfReader pdfReader = new PdfReader("f:/itext-demo.pdf");         // Get the PdfStamper object         PdfStamper pdfStamper = new PdfStamper(pdfReader             , new FileOutputStream(                 "f:/itext-demo22.pdf"));         addWatermark(pdfStamper, "www.360sdn.com");            pdfStamper.close();      }         private static void addWatermark(PdfStamper pdfStamper           , String waterMarkName) {             PdfContentByte content = null;             BaseFont base = null;             Rectangle pageRect = null;             PdfGState gs = new PdfGState();             try {                 // 设置字体             base = BaseFont.createFont("STSongStd-Light",  "UniGB-UCS2-H",         BaseFont.NOT_EMBEDDED);             } catch (DocumentException e) {                 e.printStackTrace();             } catch (IOException e) {                 e.printStackTrace();             }             try {                 if (base == null || pdfStamper == null) {                     return;                 }                 // 设置透明度为0.4                 gs.setFillOpacity(0.4f);                 gs.setStrokeOpacity(0.4f);                 int toPage = pdfStamper.getReader().getNumberOfPages();                 for (int i = 1; i <= toPage; i++) {                     pageRect = pdfStamper.getReader().                        getPageSizeWithRotation(i);                     // 计算水印X,Y坐标                     float x = pageRect.getWidth() / 2;                     float y = pageRect.getHeight() / 2;                     //获得PDF最顶层                     content = pdfStamper.getOverContent(i);                     content.saveState();                     // set Transparency                     content.setGState(gs);                     content.beginText();                     content.setColorFill(BaseColor.GRAY);                     content.setFontAndSize(base, 60);                     // 水印文字成45度角倾斜                     content.showTextAligned(Element.ALIGN_CENTER                             , waterMarkName, x,                             y, 45);                     content.endText();                  }             } catch (Exception ex) {                 ex.printStackTrace();             } finally {                 content = null;                 base = null;                 pageRect = null;             }         }  }