ORA-01157:cannot identify/local data file

Error info:
ORA-01157: cannot identify/lock data file 5
ORA-01110: data file 5 ‘/u01/app/oracle/oradata/SID/users02.dbf’

Solution1:
> sqlplus / as sysdba
SQL> startup mount;
SQL> alter database datafile  ‘/u01/app/oracle/oradata/SID/users02.dbf‘ offline drop;
SQL> alter database open;
Database altered.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup

Solution2:
SQL>startup mount;
SQL>recover datafile filename;
SQL>alter database open;

Doc:
http://oracle.na7.info/11_2_datafile.html