关键代码
String sql = "select * from wuliu.order where orderid = ? ";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1,Integer.parseInt(orderid));
ResultSet rs=ps.executeQuery(sql);
错误信息： You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 1

是不是问号用全角而不是半角了

之前常不小心出错是 sql语句后面加了;

con吧应该、