java 读取PDF文件生成图片形式

浅浅的花香味﹌ 2023-01-02 02:29 176阅读 0赞

引入所需maven依赖

<dependency>
            <groupId>org.icepdf.os</groupId>
            <artifactId>icepdf-core</artifactId>
            <version>6.2.2</version>
            <exclusions>
                <exclusion>
                    <groupId>javax.media</groupId>
                    <artifactId>jai_core</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

JAVA代码工具类

package com.util;
    
    import com.lowagie.text.pdf.PdfReader;
    import lombok.extern.slf4j.Slf4j;
    import org.icepdf.core.pobjects.Document;
    import org.icepdf.core.pobjects.Page;
    import org.icepdf.core.util.GraphicsRenderingHints;
    import org.springframework.web.multipart.MultipartFile;
    import javax.imageio.ImageIO;
    import javax.servlet.http.HttpServletResponse;
    import java.awt.image.BufferedImage;
    import java.io.BufferedInputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.net.URLEncoder;
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.List;
    import java.util.zip.ZipEntry;
    import java.util.zip.ZipOutputStream;
    
    //java 项目 www.fhadmin.org
    @Slf4j
    public class PdfToImageUtil {
    
        //支持文件格式
        public static final String SUPPORT_FILE = "pdf";
        //图片文件格式
        public static final String IMAGE_SUFFIX = "jpg"; //png
        //压缩文件格式
        public static final String ZIP_SUFFIX = "zip";
        //PDF是否为一页
        private static boolean isImage;
    
        /**
         * 对外的开放接口，用于将PDF文件转换为图片文件压缩包进行下载
         * @param file SpringMVC获取的图片文件
         */
        public static synchronized void pdfToTransformation(MultipartFile file, HttpServletResponse response) throws Exception {
            String fileName = file.getOriginalFilename();
            if(null == fileName) return;
            String suffix = fileName.substring(fileName.lastIndexOf(".") + 1);
            log.info("文件名称：" + fileName + ",文件后缀：" + suffix);
            if(!SUPPORT_FILE.equals(suffix)) return;
            isImage = false;
            File imageFile = generateFile(file);
            log.info("文件生成成功!");
            downloadFile(imageFile, response);
        }
    
        /**
         * 将PDF文件转换为多张图片并放入一个压缩包中
         * @param file SpringMVC获取的图片文件
         * @return 图片文件压缩包
         * @throws Exception 抛出异常
         */
        private static File generateFile(MultipartFile file) throws Exception {
            String fileName = file.getOriginalFilename();
            if(null == fileName) return null;
            Document document = new Document();
            document.setByteArray(file.getBytes(), 0, file.getBytes().length, fileName);
            log.info("PDF页数：" + document.getNumberOfPages());
            isImage = 1 == document.getNumberOfPages();
            File imageReturnFile = null;
            List<File> fileList = new ArrayList<>();
            for (int i = 0; i < document.getNumberOfPages(); i++) {
                BufferedImage image = (BufferedImage) document.getPageImage(i, GraphicsRenderingHints.SCREEN,
                        Page.BOUNDARY_CROPBOX, 0F, 2.5F);
                File imageFile = new File((i + 1) + "." + IMAGE_SUFFIX);
                ImageIO.write(image, IMAGE_SUFFIX, imageFile);
                image.flush();
                if(isImage){
                    imageReturnFile = imageFile;
                    break;
                }
                fileList.add(imageFile);
            }
            document.dispose();
            if(isImage) return imageReturnFile;
            //压缩图片文件
            String directoryName = fileName.substring(0, fileName.lastIndexOf("."));
            File zipFile = new File(directoryName + "." + ZIP_SUFFIX);
            ZipOutputStream zipOutputStream = new ZipOutputStream(new FileOutputStream(zipFile));
            zipFile(fileList, zipOutputStream);
            zipOutputStream.close();
            return zipFile;
        }
    
        /**
         * 下载image/zip文件
         * @param downloadFile 文件
         * @param response HttpServletResponse
         * @throws IOException IO异常
         */
        private static void downloadFile(File downloadFile, HttpServletResponse response) throws IOException {
            FileInputStream fileInputStream = new FileInputStream(downloadFile);
            byte[] bytes = new byte[fileInputStream.available()];
            fileInputStream.read(bytes);
            fileInputStream.close();
            //设置response参数
            response.reset();
            if(isImage){
                response.setContentType("image/jpeg");
            } else {
                response.setContentType("application/zip");
            }
            response.setCharacterEncoding("UTF-8");
            response.setHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(downloadFile.getName(), "UTF-8"));
            OutputStream outputStream = response.getOutputStream();
            outputStream.write(bytes);
            outputStream.flush();
            outputStream.close();
            if(!isImage) downloadFile.delete();
        }
    
        /**
         * 压缩文件
         * @param inputFiles 具体需要压缩的文件集合
         * @param zipOutputStream ZipOutputStream对象
         * @throws IOException IO异常
         */
        private static void zipFile(List<File> inputFiles, ZipOutputStream zipOutputStream) throws IOException {
            byte[] buffer = new byte[1024];
            for (File file : inputFiles) {
                if (file.exists()) {
                    if (file.isFile()) {
                        BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
                        zipOutputStream.putNextEntry(new ZipEntry(file.getName()));
                        int size = 0;
                        while ((size = bis.read(buffer)) > 0) {
                            zipOutputStream.write(buffer, 0, size);
                        }
                        zipOutputStream.closeEntry();
                        bis.close();
                        file.delete();
                    } else {
                        File[] files = file.listFiles();
                        if(null == files) continue;
                        List<File> childrenFileList = Arrays.asList(files);
                        zipFile(childrenFileList, zipOutputStream);
                    }
                }
            }
        }
    
        /**
         * 获取PDF页数
         * @throws IOException
         */
        public static String getPdfPageSize(MultipartFile file) throws IOException {
            PdfReader pdfReader = new PdfReader(file.getBytes());
            int pages = pdfReader.getNumberOfPages();
            return String.valueOf(pages);
        }
    }

生成图片PdfController.java

package com.web.transformation.controller;
    
    import com.util.PdfToImageUtil;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    import org.springframework.web.multipart.MultipartFile;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    //java项目 www.fhadmin.org
    @Controller
    public class PdfController {
    
        //PDF转图片或者ZIP
        @RequestMapping("/pdfToImage")
        @ResponseBody
        public void pdfToImage(MultipartFile file, HttpServletResponse response) throws Exception{
            PdfToImageUtil.pdfToTransformation(file,response);
        }
    
        //获取PDF页数
        @RequestMapping("/getPdfPageSize")
        @ResponseBody
        public String pdfToImage(MultipartFile file) throws IOException {
            return PdfToImageUtil.getPdfPageSize(file);
        }
    
    }

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