public int denglu(String name,String password) throws ClassNotFoundException, SQLException { int flag=0; try{ java.sql.DriverManager.registerDriver(new com.mysql.jdbc.Driver()); } catch(SQLException ex) { System.err.println("连接失败"); System.exit(1); } String URL = "jdbc:mysql://localhost:3306/denglu";try{ Connection con = java.sql.DriverManager.getConnection(URL,"root","891123"); String sql = "select ID from login where ID=? and mima=?"; PreparedStatement stmt = con.prepareStatement(sql); stmt.setString(1,name); stmt.setString(2,password); ResultSet rs = stmt.executeQuery(sql); while (rs.next()) { //该用户合法 flag=1; } rs.close(); stmt.close(); con.close();} catch(SQLException e){System.out.print(e);} return flag; }不知道为什么会出现： You have an error in your SQL syntax; check the manual that corresponds to your MySQL