如何使用Springboot REST从数据库下载记录

// 实体类
@Entity
@Table(name = "records")
public class Record {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    // 省略其他属性和方法
}

// 数据访问层接口
public interface RecordRepository extends JpaRepository<Record, Long> {
    @Query("SELECT r FROM Record r")
    List<Record> findAllRecords();
}

// 控制器
@RestController
public class RecordController {
    @Autowired
    private RecordRepository recordRepository;

    @GetMapping("/download")
    public ResponseEntity<Resource> downloadRecords() throws IOException {
        List<Record> records = recordRepository.findAllRecords();

        // 创建一个CSV文件，并将记录写入其中
        File file = File.createTempFile("records", ".csv");
        FileWriter writer = new FileWriter(file);
        for (Record record : records) {
            writer.write(record.getName() + "\n");
        }
        writer.close();

        // 设置HTTP头信息，使浏览器能够正确地下载文件
        HttpHeaders headers = new HttpHeaders();
        headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=records.csv");

        // 将文件转换为Resource对象，并返回给客户端
        Resource resource = new FileSystemResource(file);
        return ResponseEntity.ok()
                .headers(headers)
                .contentType(MediaType.APPLICATION_OCTET_STREAM)
                .body(resource);
    }
}