<dependencies>
    <!-- PDFBox -->
    <dependency>
        <groupId>org.apache.pdfbox</groupId>
        <artifactId>pdfbox</artifactId>
        <version>2.0.24</version>
    </dependency>

    <!-- Spring Boot Starter Web (如果你還沒有添加) -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

import org.apache.pdfbox.pdmodel.PDDocument;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

@RestController
public class PdfExportController {

    @PostMapping("/export/pdf")
    public ResponseEntity<byte[]> exportPdf(@RequestBody String base64Pdf) {
        // 移除Base64的編碼前綴（如果有的話）
        base64Pdf = base64Pdf.replaceFirst("data:application/pdf;base64,", "");

        // Base64解碼
        byte[] pdfBytes = java.util.Base64.getDecoder().decode(base64Pdf);

        // 這里其實(shí)已經(jīng)解碼成了PDF的字節(jié)流，但為了演示如何操作PDF，我們可以選擇加載并重新保存
        // 實(shí)際應(yīng)用中，如果直接返回解碼后的字節(jié)流即可

        // 如果需要對(duì)PDF進(jìn)行進(jìn)一步處理，可以加載這個(gè)PDF
        // PDDocument doc = PDDocument.load(new ByteArrayInputStream(pdfBytes));
        // ... 進(jìn)行PDF處理 ...
        // doc.save(new FileOutputStream("path/to/save/modified.pdf"));
        // doc.close();

        // 如果沒有修改，直接返回原始PDF字節(jié)流
        HttpHeaders headers = new HttpHeaders();
        headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=downloaded.pdf");
        headers.add(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_PDF_VALUE);

        return new ResponseEntity<>(pdfBytes, headers, HttpStatus.OK);
    }
}