请问这个代码有什么问题吗?为什么会出现这样的错误提示?
Connection con = ConnectDatabase.connectDB();
Date borrowdate = new Date ();
String sql1 = "update book311 set position='外借'";
String sql2 = "insert into usbk(account,bookname,borrowdate)"+"values('"+accountt+"','"+bookname+"',"+borrowdate+")";
