不支持Spring boot POST PDF内容类型'application/pdf

<dependency>
  <groupId>com.itextpdf</groupId>
  <artifactId>itextpdf</artifactId>
  <version>5.5.13.2</version>
</dependency>
<dependency>
  <groupId>org.apache.commons</groupId>
  <artifactId>commons-io</artifactId>
  <version>1.3.2</version>
</dependency>

import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import org.apache.commons.io.IOUtils;

import java.io.FileOutputStream;
import java.io.IOException;

@RestController
public class PDFController {

    @PostMapping("/upload")
    public String uploadPDF(@RequestBody MultipartFile file) {
        try {
            byte[] bytes = file.getBytes();
            // 将上传的 PDF 文件保存到服务器
            FileOutputStream fos = new FileOutputStream("uploaded.pdf");
            IOUtils.write(bytes, fos);
            fos.close();
            return "Upload success!";
        } catch (IOException e) {
            e.printStackTrace();
            return "Upload failed.";
        }
    }
}

spring.servlet.multipart.max-file-size=10MB
spring.servlet.multipart.max-request-size=10MB

POST /upload
Content-Type: application/pdf

[PDF 文件内容]