图片转为pdf，直接调用代码传入图片地址和保存pdf地址即可

import com.itextpdf.text.Document;
import com.itextpdf.text.Image;
import com.itextpdf.text.pdf.PdfWriter;
import java.io.FileOutputStream;

	/**
    * @param imgPaths          图片地址
    * @param pdf_save_address  pdf保存地址
    */
   public static void imageToPDF(String imgPaths, String pdf_save_address) {
       try {
           Document document = new Document();
           PdfWriter.getInstance(document, new FileOutputStream(pdf_save_address));
           document.open();
           Image img = Image.getInstance(imgPaths);
           float scale = ((document.getPageSize().getWidth() - document.leftMargin()
                   - document.rightMargin() - 0) / img.getWidth()) * 100;
           img.scalePercent(scale);
           img.setAlignment(Image.ALIGN_CENTER | Image.ALIGN_TOP);
           document.add(img);
           document.close();
       } catch (Exception e) {
		e.printStackTrace();
       }
   }

iTextpdf.jar下载