spring boot上传文件只允许图片

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

@RestController
@RequestMapping("/upload")
public class FileUploadController {

    @PostMapping("/image")
    public String uploadImage(@RequestParam("file") MultipartFile file) {
        // 校验文件类型
        if (!isImage(file)) {
            return "只允许上传图片文件";
        }

        // 保存文件
        try {
            String fileName = file.getOriginalFilename();
            String filePath = "/path/to/save/image/" + fileName;
            file.transferTo(new File(filePath));
            return "文件上传成功";
        } catch (IOException e) {
            e.printStackTrace();
            return "文件上传失败";
        }
    }

    private boolean isImage(MultipartFile file) {
        // 根据文件后缀名或MIME类型判断文件是否为图片类型
        String fileName = file.getOriginalFilename();
        String fileExtension = fileName.substring(fileName.lastIndexOf(".") + 1).toLowerCase();
        return fileExtension.equals("jpg") || fileExtension.equals("jpeg") || fileExtension.equals("png");
    }
}