springboot 下载文件

import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
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;

@RestController
public class FileDownloadController {

    @GetMapping("/download/{fileName}")
    public ResponseEntity<Resource> downloadFile(@PathVariable String fileName) {
        Resource resource = new ClassPathResource("files/" + fileName);
        String contentType = "application/octet-stream";
        return ResponseEntity.ok()
                .contentType(MediaType.parseMediaType(contentType))
                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")
                .body(resource);
    }
}

if (!resource.exists()) {
    return ResponseEntity.notFound().build();
}

import org.springframework.core.io.InputStreamResource;
import java.io.File;
import java.io.FileInputStream;

File file = new File("path/to/file");
InputStreamResource resource = new InputStreamResource(new FileInputStream(file));

@PreAuthorize("hasRole('ROLE_USER')")
@GetMapping("/download/{fileName}")
public ResponseEntity<Resource> downloadFile(@PathVariable String fileName) {
    // 文件下载逻辑
}