JavaOracle Exhausted Result

Question

我一直在尝试修复任何错误，但仍然会导致结果集错误。我的代码有什么问题吗？

   stmt=con.createStatement();
   String sql = "SELECT * FROM CUSTOMER";
   rs=stmt.executeQuery(sql);

   rs.next();
           int id_col = rs.getInt("CUSTOMER_ID");
           String id = Integer.toString(id_col);
           String name= rs.getString("CUSTOMER_NAME");
           String address = rs.getString("CUSTOMER_ADDRESS");
           String phone = rs.getString ("CUSTOMER_PHONE");
           String email = rs.getString ("CUSTOMER_EMAIL");

           textID.setText(id);
           textName.setText(name);
           textAddress.setText(address);
           textPhone.setText(phone);
           textEmail.setText(email);


    }
    catch (SQLException err) {
        JOptionPane.showMessageDialog(ComputerShop.this,err.getMessage());
    }

}

Answer 1

通过阅读它在Java中看起来像SQL的代码，我理解了什么。例如，如果您尝试从单个表中选择乘法行，则也可以这样做。

public static void customerName(Connection b, String c) throws SQLException
{
    c = "'"+c+"'";

    try
    {
        b = DriverManager.getConnection(dbURL, user, password);
        b.clearWarnings();
        stmt = b.createStatement();
        ResultSet rs = stmt.executeQuery("SELECT CONTACTNAME FROM CUSTOMERS WHERE CUSTOMERID =" + c); // this is basicly where you install the SQL code minus the ";" at the end.

        while(rs.next())
        {
            System.out.print(rs.getString("CONTACTNAME") + " ");
        }
    }
        catch(SQLException e)
        {
            System.err.println(e.getMessage());
        }
    finally
    {
        if(!b.isClosed())
        {
        b.close();  
        }

    }

}   

我发现这通常有助于我保持一切清洁并组织我的代码。这将是我从我连接到数据库的主方法调用的方法。