POST方法提交请求时，List类型映射失败

{"phone":"13333333333","orderId":"156456456","fileList":[{"file":"a.txt","num":"1"},{"file":"b.txt","num":"2"}]}

@Data
@Builder
@ToString
public class MergeRequestVo {
    private String phone;
    private String orderId;
    private List<MergeRequestFileListVo> fileList;

    @Data
    @ToString
    public class MergeRequestFileListVo {
       private String file;
       private String num;
    }
}

@PostMapping("/transfer")
public String transfer(@RequestBody MergeRequestVo data){
……
}