java 如何处理每行数据的列数不一致问题？

Question

数据如下（逗号分割）：
13701912508,20180310,14:51,123,456,156,365,789
13951863852,20180312,8:58,123,456,156,365,789,698
15968339885,20180312,16:15,456,156,365
13757327050,20180313,13:35,365,789,698
13958037749,20180314,15:47,365
15958366077,20180315,15:36,456,156
18357378777,20180315,15:32,698
13905731841,20180317,0:16,456,2