springboot 使用itextpdf 框架实现多个图片合成一个pdf文件

以下两个方法引入头

import com.lowagie.text.*;
import com.lowagie.text.pdf.PdfWriter;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.ImageType;
import org.apache.pdfbox.rendering.PDFRenderer;
import org.springframework.stereotype.Component;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;

1、图片转pdf文件

pom 文件引入

    <dependency>
            <groupId>com.lowagie</groupId>
            <artifactId>itext</artifactId>
            <version>2.1.7</version>
        </dependency>

 public File imageToPdf(List<String> imageUrllist, String mOutputPdfFileName) {

        String TAG = "PdfManager";
        Document doc = new Document(PageSize.A4, 20, 20, 20, 20);
        try {
            PdfWriter.getInstance(doc, new FileOutputStream(mOutputPdfFileName));
            doc.open();
            for (int i = 0; i < imageUrllist.size(); i++) {
                doc.newPage();
//                doc.add(new Paragraph("简单使用iText"));
                Image png1 = Image.getInstance(imageUrllist.get(i));
                float heigth = png1.getHeight();
                float width = png1.getWidth();
                int percent = getPercent2(heigth, width);
                png1.setAlignment(Image.MIDDLE);
                png1.scalePercent(percent+3);// 表示是原来图像的比例;
                doc.add(png1);
            }

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            doc.close();

        }
        File mOutputPdfFile = new File(mOutputPdfFileName);
        if (!mOutputPdfFile.exists()) {
            mOutputPdfFile.deleteOnExit();
            return null;
        }
        return mOutputPdfFile;
    }

/**
 * 第一种解决方案 在不改变图片形状的同时，判断，如果h>w，则按h压缩，否则在w>h或w=h的情况下，按宽度压缩
 *
 * @param h
 * @param w
 * @return
 */
private  int getPercent(float h, float w) {
    int p = 0;
    float p2 = 0.0f;
    if (h > w) {
        p2 = 297 / h * 100;
    } else {
        p2 = 210 / w * 100;
    }
    p = Math.round(p2);
    return p;
}

/**
 * 第二种解决方案，统一按照宽度压缩 这样来的效果是，所有图片的宽度是相等的，自我认为给客户的效果是最好的
 *
 * @param
 */
private int getPercent2(float h, float w) {
    int p = 0;
    float p2 = 0.0f;
    p2 = 530 / w * 100;
    p = Math.round(p2);
    return p;
}

2、pdf 转图片

pom 引入

<dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>pdfbox</artifactId>
            <version>2.0.1</version>
        </dependency>

 //经过测试,dpi为96,100,105,120,150,200中,105显示效果较为清晰,体积稳定,dpi越高图片体积越大
    //一般电脑显示分辨率为96
    public static final float DEFAULT_DPI=105;
    /**pdf转图片
     * @param pdfPath
     */
    public  String pdfToImage(String pdfPath, HttpServletResponse res, HttpServletRequest request){
        try{
            if(pdfPath==null||"".equals(pdfPath)||!pdfPath.endsWith(".pdf"))
                return null;
            //图像合并使用参数
            int width = 0; // 总宽度
            int[] singleImgRGB; // 保存一张图片中的RGB数据
            int shiftHeight = 0;
            BufferedImage imageResult = null;//保存每张图片的像素值
            //利用PdfBox生成图像
            PDDocument pdDocument = PDDocument.load(new File(pdfPath));
            PDFRenderer renderer = new PDFRenderer(pdDocument);
            //循环每个页码
            for(int i=0,len=pdDocument.getNumberOfPages(); i<len; i++){
                BufferedImage image=renderer.renderImageWithDPI(i, DEFAULT_DPI, ImageType.RGB);
                int imageHeight=image.getHeight();
                int imageWidth=image.getWidth();
                if(i==0){//计算高度和偏移量
                    width=imageWidth;//使用第一张图片宽度;
                    //保存每页图片的像素值
                    imageResult= new BufferedImage(width, imageHeight*len, BufferedImage.TYPE_INT_RGB);
                }else{
                    shiftHeight += imageHeight; // 计算偏移高度
                }
                singleImgRGB= image.getRGB(0, 0, width, imageHeight, null, 0, width);
                imageResult.setRGB(0, shiftHeight, width, imageHeight, singleImgRGB, 0, width); // 写入流中
            }
            pdDocument.close();
            String outPath = pdfPath.replace(".pdf", "_"+DEFAULT_DPI+".jpg");
            File outFile = new File(outPath);
            ImageIO.write(imageResult, "jpg", outFile);// 写图片

            return outPath;
        }catch (Exception e) {
            e.printStackTrace();
        }
          return null;
    }