java.lang.NullPointerException,文本导入sql server时异常

Connection con = null;
ResultSet rs = null;
Statement smt = null;

try
{
con = ConnectionManager.getConnection();

// 将用户上行记录存入userinput表中

String sql= "insert into userinput from " + file + " with (fieldterminator= ', ',rowterminator= '\n ') ";

smt.executeUpdate(sql);
smt.close();smt=null;
con.close();con=null;
}
catch(Exception e)
{

try{if(smt!=null) smt.close();}catch(SQLException sqle){}
try{if(con!=null) con.close();}catch(SQLException sqle){}

}


------解决方法--------------------------------------------------------
smt.executeUpdate(sql);

这个smt你就没创建，怎么能用呢，不NullPointerException才怪

smt=con.createStatement();