Spring Boot:文件下载在项目根文件夹中创建一个新文件

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

import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.io.IOException;
import java.net.MalformedURLException;
import java.nio.file.Path;
import java.nio.file.Paths;

@RestController
public class FileDownloadController {

    @GetMapping("/download/{fileName}")
    public ResponseEntity<Resource> downloadFile(@PathVariable String fileName) {
        // 构建文件路径
        Path filePath = Paths.get("./" + fileName).normalize();
        try {
            // 加载文件资源
            Resource resource = new UrlResource(filePath.toUri());
            if (resource.exists()) {
                // 设置响应头信息
                HttpHeaders headers = new HttpHeaders();
                headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=" + resource.getFilename());
                headers.add(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_OCTET_STREAM_VALUE);
                // 构建响应对象
                return ResponseEntity.ok()
                        .headers(headers)
                        .body(resource);
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        // 文件不存在时返回404错误
        return ResponseEntity.notFound().build();
    }
}