嗨，我怎样才能用一笔交易来操作别人的道？

Question

我知道在一个事务中应该使用哪些方法正确执行此操作的最佳方法是什么？ Car dao有以下方法

public Car findCar(int numOfPas,String carCategory){
        String query = "SELECT*FROM car_info WHERE numOfPas = ? AND carCategory=? AND carState='ready' ORDER BY RAND() LIMIT 1;";
        Car foundCar = null;
        ResultSet resultSet = null;
        try (Connection connection = MySQLDAOFactory.getConnection();
             PreparedStatement statement = connection.prepareStatement(query)){
            statement.setInt(1,numOfPas);
            statement.setString(2,carCategory);
            resultSet =statement.executeQuery();
            if(resultSet.next()){
                foundCar = new Car();
                foundCar.setCarId(resultSet.getInt("carId"));
                foundCar.setCarCategory(resultSet.getString("carCategory"));
                foundCar.setNumOfPas(resultSet.getInt("numOfPas"));
                foundCar.setCarState(resultSet.getString("carState"));
                foundCar.setCarName(resultSet.getString("carName"));
                foundCar.setCarImage(manager.byteToImage(resultSet.getBytes("carImage")));
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            if(resultSet!=null){
                try {
                    resultSet.close();
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
        }
        return foundCar;

    }

Order Dao 有以下内容

@Override
    public boolean insertOrder(Order order) {
        int rowNum = 0;
        String query = "INSERT INTO user_order(userId,carId,userAddress,userDestination,orderCost,orderDate) values(?,?,?,?,?,?)";
        ResultSet keys = null;
        try (Connection connection = MySQLDAOFactory.getConnection();
             PreparedStatement statement = connection.prepareStatement(query,Statement.RETURN_GENERATED_KEYS)){

            statement.setInt(1,order.getUserId());
            statement.setInt(2,order.getCarId());
            statement.setString(3, order.getUserAddress());
            statement.setString(4, order.getUserDestination());
            statement.setDouble(5,order.getOrderCost());
            statement.setTimestamp(6, Timestamp.valueOf(order.getOrderDate()));
            rowNum = statement.executeUpdate();
            keys = statement.getGeneratedKeys();
            if(keys.next()){
                order.setOrderId(keys.getInt(1));
            }

        } catch (SQLException throwables) {

            throwables.printStackTrace();
        }

        return rowNum>0;
    }

如何将这些操作放在一个事务中？我通过 Apache dhcp 连接池接收连接。

Edited

这是class 我在哪里得到连接 public class MySQLDAOFactory 扩展 DAOFactory {

    public static Connection getConnection(){

        Connection conn = null;
        try {
            Context initContext = new InitialContext();
            Context envContext = (Context) initContext.lookup("java:comp/env");
            DataSource ds = (DataSource) envContext.lookup("jdbc/UsersDB");
            conn = ds.getConnection();
        } catch (NamingException | SQLException e) {
            e.printStackTrace();
        }

        return conn;
    }
    @Override
    public CarDao getCarDao() {
        return new MySQLCarDao();
    }

    @Override
    public UserDao getUserDao() {
        return new MySQLUserDao();
    }
    @Override
    public OrderDao getOrderDao() {
        return new MySQLOrderDao();
    }

    @Override
    public CarCategoryDao getCarCategoryDao() {
        return new MySQLCarCategoryDao();
    }
}

Answer 1

管理交易的方式有很多种。根据您的代码，最简单的方法是：

在 try 块中：

在包装两个调用的调用方中创建您的 connection
执行connection.setAutoCommit(false)
调用每个方法 findCar() 和 insertOrder()
致电connection.commit();

在catch块中：

致电connection.rollback()

connection 不是在这些函数之外创建的，所以不要忘记从每个函数中删除连接设置。

嗨，我怎样才能用一笔交易来操作别人的道？

Hi, How can i do operation of others dao with one transaction?

java

mysql

dao

jdbc

apache-commons-dbcp