Method deleteAll

ch3/UserDao.java:146–153

()

    }

    public void deleteAll() throws Exception {
        Connection conn = ds.getConnection();

        String sql = "delete from user_info ";

        PreparedStatement pstmt = conn.prepareStatement(sql); // SQL Injection공격, 성능향상
        pstmt.executeUpdate(); //  insert, delete, update
    }

    private void close(AutoCloseable... acs) {
        for(AutoCloseable ac :acs)