【SpringBoot+Layui实现pdf下载实现加水印功能】

SpringBoot+Layui实现pdf下载实现加水印功能

1、引入第三方包

com.itextpdf itextpdf 5.5.13 com.itextpdf itext-asian 5.2.0 2、水印帮助方法

package com.example.pdf.demo.util;

import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Element;
import com.itextpdf.text.Rectangle;
import com.itextpdf.text.pdf.*;

import javax.swing.;
import java.awt.;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

/**

• @author tiankk
  */
  public class PdfUtils {

  /**

  • pdf添加水印

  • @param inputFile 需要添加水印的文件

  • @param outputFile 添加完水印的文件存放路径

  • @param waterMarkName 需要添加的水印文字

  • @param opacity 水印字体透明度

  • @param fontsize 水印字体大小

  • @param angle 水印倾斜角度（0-360）

  • @param heightdensity 数值越大每页竖向水印越少

  • @param widthdensity 数值越大每页横向水印越少

  • @param cover 是否覆盖

  • @return
    */
    public static boolean addwaterMark(String inputFile, String outputFile, String waterMarkName,
    float opacity, int fontsize, int angle, int heightdensity, int widthdensity,boolean cover) {
    if (!cover){
    File file=new File(outputFile);
    if (file.exists()){
    return true;
    }
    }
    File file=new File(inputFile);
    if (!file.exists()){
    return false;
    }

    PdfReader reader = null;
    PdfStamper stamper = null;
    try {
    int interval = -5;
    reader = new PdfReader(inputFile);
    stamper = new PdfStamper(reader, new FileOutputStream(outputFile));
    BaseFont base = BaseFont.createFont(“STSong-Light”, “UniGB-UCS2-H”, BaseFont.EMBEDDED);
    Rectangle pageRect = null;
    PdfGState gs = new PdfGState();
    //这里是透明度设置
    gs.setFillOpacity(opacity);
    //这里是条纹不透明度
    gs.setStrokeOpacity(0.2f);
    int total = reader.getNumberOfPages() + 1;
    System.out.println(“Pdf页数：” + reader.getNumberOfPages());
    JLabel label = new JLabel();
    FontMetrics metrics;
    int textH = 0;
    int textW = 0;
    label.setText(waterMarkName);
    metrics = label.getFontMetrics(label.getFont());
    //字符串的高, 只和字体有关
    textH = metrics.getHeight();
    //字符串的宽
    textW = metrics.stringWidth(label.getText());
    PdfContentByte under;
    //这个循环是确保每一张PDF都加上水印
    for (int i = 1; i < total; i++) {
    pageRect = reader.getPageSizeWithRotation(i);
    under = stamper.getOverContent(i); //在内容上方添加水印
    //under = stamper.getUnderContent(i); //在内容下方添加水印
    under.saveState();
    under.setGState(gs);
    under.beginText();
    //under.setColorFill(BaseColor.PINK); //添加文字颜色 不能动态改变 放弃使用
    under.setFontAndSize(base, fontsize); //这里是水印字体大小
    for (int height = textH; height < pageRect.getHeight() * 2; height = height + textH * heightdensity) {
    for (int width = textW; width < pageRect.getWidth() * 1.5 + textW; width = width + textW * widthdensity) {
    // rotation:倾斜角度
    under.showTextAligned(Element.ALIGN_LEFT, waterMarkName, width - textW, height - textH, angle);
    }
    }
    //添加水印文字
    under.endText();
    }
    System.out.println(“添加水印成功！”);
    return true;
    } catch (IOException e) {
    System.out.println("添加水印失败！错误信息为: " + e);
    e.printStackTrace();
    return false;
    } catch (DocumentException e) {
    System.out.println("添加水印失败！错误信息为: " + e);
    e.printStackTrace();
    return false;
    } finally {
    //关闭流
    if (stamper != null) {
    try {
    stamper.close();
    } catch (DocumentException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    if (reader != null) {
    reader.close();
    }
    }
    }
    }
    3、调用帮助方法并输出文件流

package com.example.pdf.demo.controller;

import com.example.pdf.demo.util.PdfUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.UUID;

/**

• @author tiankk
  */
  @RestController
  @RequestMapping(“file”)
  public class FileController {

  @GetMapping(“downloadFile/{fileName}”)
  public void downloadFile(@PathVariable(“fileName”) String fileName, HttpServletResponse response) {
  //需要添加水印的文件
  String inputFile = “E:\ChromeDownLoad\test.pdf”;
  //添加完水印的文件存放路径
  String outputFile = “E:\ChromeDownLoad\test(水印).pdf”;
  //需要添加的水印文字
  String waterMarkName = “测试水印”;
  //水印字体透明度
  float opacity = 0.3f;
  //水印字体大小
  int fontsize = 30;
  //水印倾斜角度（0-360）
  int angle = 30;
  //数值越大每页竖向水印越少
  int heightdensity = 20;
  //数值越大每页横向水印越少
  int widthdensity = 4;

   PdfUtils.addwaterMark(inputFile, outputFile, waterMarkName, opacity, fontsize, angle, heightdensity, widthdensity,false);
  
   fileName = UUID.randomUUID().toString() + "_" + fileName + ".pdf";
   String path = null;
   response.setHeader("content-type", "application/octet-stream");
   response.setContentType("application/octet-stream");
   try {
       response.setHeader("Content-Disposition", "attachment;filename=" + java.net.URLEncoder.encode(fileName, "UTF-8"));
   } catch (UnsupportedEncodingException e2) {
       e2.printStackTrace();
   }
   byte[] buff = new byte[1024];
   BufferedInputStream bis = null;
   OutputStream os = null;
   try {
       path = "E:\\ChromeDownLoad";
       os = response.getOutputStream();
       bis = new BufferedInputStream(new FileInputStream(new File(path + "\\少有人走的路[派克](水印).pdf")));
       int i = bis.read(buff);
       while (i != -1) {
           os.write(buff, 0, buff.length);
           os.flush();
           i = bis.read(buff);
       }
   } catch (FileNotFoundException e1) {
   } catch (IOException e) {
       e.printStackTrace();
   } finally {
       if (bis != null) {
           try {
               bis.close();
           } catch (IOException e) {
               e.printStackTrace();
           }
       }
   }
  

  }
  }