JAva接続mysql削除操作

public void deleteStudent(int sid){
		
		DBConnection db=new DBConnection();
		PreparedStatement preStmt=null;
		try {
			preStmt=db.getConn().prepareStatement("delete from student where sid=?");
			preStmt.setInt(1, sid);
			preStmt.executeUpdate();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

//   jsp    

		 students = (ArrayList) request
					.getAttribute("students");
			if (students != null) {
				for (int i = 0; i < students.size(); i++) {
		%>