嗨，我如何通过一笔交易来操作其他dao？

如何解决嗨，我如何通过一笔交易来操作其他dao？

我有 dao 哪些方法应该在一个事务中正确执行的最佳方法是什么？车道有以下方法

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;

    }

而令道有以下内容

@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笔交易中？我通过 Apache dhcp 连接池接收连接。

已编辑

这是课堂我在哪里建立联系公共类 MysqLDAOFactory 扩展了 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();
    }
}

解决方法

管理交易的方式有很多种。鉴于您的代码，最简单的方法是：

在 try 块中：

在包含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：

调用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。