Java Spring Boot PDF 上传并按页数重命名为图片保存

1. 首先需要引入相关依赖，包括 Spring Boot、Apache Commons FileUpload 和 iTextPDF。

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.4</version>
</dependency>

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13.2</version>
</dependency>

2. 创建一个 Controller 来处理文件上传请求，并将上传的文件保存到本地。

@RestController
public class FileUploadController {

    @PostMapping("/upload")
    public String uploadFile(@RequestParam("file") MultipartFile file) {
        if (file.isEmpty()) {
            return "File is empty";
        }

        try {
            byte[] bytes = file.getBytes();
            Path path = Paths.get(file.getOriginalFilename());
            Files.write(path, bytes);
            return "File uploaded successfully";
        } catch (IOException e) {
            e.printStackTrace();
        }

        return "Error uploading file";
    }

}

3. 在上传文件的方法中，添加处理 PDF 文件的代码。使用 iTextPDF 库将 PDF 文件转换为多个图片，并将每个图片重命名为其页数。

@PostMapping("/upload")
public String uploadFile(@RequestParam("file") MultipartFile file) {
    if (file.isEmpty()) {
        return "File is empty";
    }

    try {
        byte[] bytes = file.getBytes();
        Path path = Paths.get(file.getOriginalFilename());
        Files.write(path, bytes);

        // Convert PDF to images and rename them by page number
        PdfReader reader = new PdfReader(path.toString());
        for (int i = 1; i <= reader.getNumberOfPages(); i++) {
            String imageName = "page_" + i + ".png";
            FileOutputStream fos = new FileOutputStream(imageName);
            Image image = Image.getInstance(reader, i);
            BufferedImage bufferedImage = image.getBufferedImage();
            ImageIO.write(bufferedImage, "png", fos);
            fos.close();
        }

        return "File uploaded successfully";
    } catch (IOException | DocumentException e) {
        e.printStackTrace();
    }

    return "Error uploading file";
}

4. 完整的 Controller 代码如下：

@RestController
public class FileUploadController {

    @PostMapping("/upload")
    public String uploadFile(@RequestParam("file") MultipartFile file) {
        if (file.isEmpty()) {
            return "File is empty";
        }

        try {
            byte[] bytes = file.getBytes();
            Path path = Paths.get(file.getOriginalFilename());
            Files.write(path, bytes);

            // Convert PDF to images and rename them by page number
            PdfReader reader = new PdfReader(path.toString());
            for (int i = 1; i <= reader.getNumberOfPages(); i++) {
                String imageName = "page_" + i + ".png";
                FileOutputStream fos = new FileOutputStream(imageName);
                Image image = Image.getInstance(reader, i);
                BufferedImage bufferedImage = image.getBufferedImage();
                ImageIO.write(bufferedImage, "png", fos);
                fos.close();
            }

            return "File uploaded successfully";
        } catch (IOException | DocumentException e) {
            e.printStackTrace();
        }

        return "Error uploading file";
    }

}