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;

    <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;}

<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96public 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;}