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

如下两个方法引入头

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;

 

一、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，若是h>w，则按h压缩，不然在w>h或w=h的状况下，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，全部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;
}

二、pdf 转图片

pom 引入

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

 

//通过测试,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 //通常电脑显示分辨率为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); //循环每一个页码
            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; }