Get方法返回空值springboot[closed]

Question

在get方法中尝试在springboot中按id查找行时，收到一个空值。我在这里对数据库的调用是否有误？

存储库-

ConnectionRequest findConnectionRequestById(Long id);

服务-

   public void getFromConnectionRequest(Long id) {
        System.out.println(id);
        connectionRequestRepository.findConnectionRequestById(id);
    }

控制器-

@GetMapping(value="/test")
public ResponseEntity<?> findConnection(Long id) {
    targetLocationService.getFromConnectionRequest(id);
    return new ResponseEntity<Authenticator.Success>(HttpStatus.OK);
}

Answer 1

您只返回一个200 http响应；如果要返回ConnectionRequest，可以在服务中更新方法：

   public ConnectionRequest getFromConnectionRequest(Long id) {
        System.out.println(id);
        return connectionRequestRepository.findConnectionRequestById(id);
    }

并在控制器中返回以下内容：

@GetMapping(value="/test")
public ResponseEntity<ConnectionRequest> findConnection(Long id) {
    ConnectionRequest result = targetLocationService.getFromConnectionRequest(id);
    return new ResponseEntity<>(result, HttpStatus.OK);
}