Mybatis插入空值时，需要制定jdbcType
?jdbcType:
BIT?????????FLOAT??????CHAR???????????TIMESTAMP???????OTHER???????UNDEFINED
TINYINT?????REAL???????VARCHAR????????BINARY??????????BLOB????????NVARCHAR
SMALLINT????DOUBLE?????LONGVARCHAR????VARBINARY???????CLOB????????NCHAR
INTEGER?????NUMERIC????DATE???????????LONGVARBINARY???BOOLEAN?????NCLOB
BIGINT??????DECIMAL????TIME???????????NULL????????????CURSOR
