Spring Boot 初学者指南：PDF 转换为图片或 Word 实现-51CTO.COM

一、工具选型与准备

Apache PDFBox ：开源 Java 工具包，解析 PDF 准确，支持内容提取、文档创建等，适合初学者。

项目依赖：在 pom.xml 中添加以下关键依赖：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.pdfbox</groupId>
        <artifactId>pdfbox</artifactId>
        <version>2.0.27</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
    </dependency>
</dependencies>

二、Spring Boot 实现 PDF 转图片

1. 文件上传功能

前端表单：用于上传 PDF 文件。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>PDF 转换为图片</title>
</head>
<body>
    <form action="/upload" method="post" enctype="multipart/form-data">
        <input type="file" name="file" accept=".pdf"/>
        <button type="submit">上传 PDF</button>
    </form>
</body>
</html>

后端接口：处理文件上传。

@PostMapping("/upload")
public ResponseEntity<String> uploadFile(@RequestParam("file") MultipartFile file) {
    try {
        // 设置文件保存路径
        Path uploadPath = Paths.get("uploads");
        if (!Files.exists(uploadPath)) {
            Files.createDirectories(uploadPath);
        }
        // 保存文件到本地
        Path filePath = Paths.get(uploadPath + "/" + file.getOriginalFilename());
        Files.copy(file.getInputStream(), filePath, StandardCopyOption.REPLACE_EXISTING);
        return ResponseEntity.ok("文件上传成功！");
    } catch (IOException e) {
        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("文件上传失败！");
    }
}

2. PDF 转图片核心逻辑

@Service
public class PdfToImageService {

    public void convertPdfToImage(String pdfPath, String outputFolder) throws IOException {
        // 加载 PDF 文件
        try (PDDocument document = PDDocument.load(new File(pdfPath))) {
            PDFRenderer renderer = new PDFRenderer(document);
            // 遍历每一页进行渲染
            for (int pageIndex = 0; pageIndex < document.getNumberOfPages(); pageIndex++) {
                BufferedImage image = renderer.renderImageWithDPI(pageIndex, 300, ImageType.RGB);
                // 保存为图片
                String imageName = "page_" + (pageIndex + 1) + ".png";
                ImageIO.write(image, "PNG", new File(outputFolder + "/" + imageName));
            }
        }
    }
}

3. 图片下载功能

@GetMapping("/download/image/{fileName}")
public ResponseEntity<InputStreamResource> downloadImage(@PathVariable String fileName) throws IOException {
    // 设置资源文件路径
    String filePath = "uploads/" + fileName;
    InputStreamResource resource = new InputStreamResource(new FileInputStream(filePath));
    HttpHeaders headers = new HttpHeaders();
    headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename=" + fileName);
    return ResponseEntity.ok()
            .headers(headers)
            .contentLength(new File(filePath).length())
            .contentType(MediaType.IMAGE_PNG)
            .body(resource);
}

三、Spring Boot 实现 PDF 转 Word

（技术文章篇幅限制，此处仅展示关键代码片段）

// 引入 OpenAPI 库
// 在 porm.xml 中添加依赖
<dependency>
    <groupId>org.apache.tika</groupId>
    <artifactId>tika-core</artifactId>
    <version>1.28.3</version>
</dependency>
<dependency>
    <groupId> org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>5.2.3</version>
</dependency>

private void convertPdfToWord(String pdfPath, String docPath) throws Exception {
    // 解析 PDF 文本
    InputStream input = new FileInputStream(pdfPath);
    ContentHandler handler = new BodyContentHandler();
    Metadata metadata = new Metadata();
    ParseContext context = new ParseContext();
    PDFParser pdfParser = new PDFParser();
    pdfParser.parse(input, handler, metadata, context);
    String text = handler.toString();

    // 将文本写入 Word 文档
    XWPFDocument document = new XWPFDocument();
    XWPFParagraph paragraph = document.createParagraph();
    XWPFRun run = paragraph.createRun();
    run.setText(text);

    // 保存 Word 文档
    FileOutputStream out = new FileOutputStream(docPath);
    document.write(out);
    out.close();
}

四、测试与运行

启动项目：运行 DocumentConverterApplication 类中的 main 方法。
上传测试：访问 /upload 接口上传 PDF 文件。
转换测试：调用 PDF 转换服务，将在指定输出路径生成图片或 Word 文件。
下载测试：访问 /download/image/{fileName} 接口，下载转换后的图片或 Word 文件。