如何利用Go语言开发点餐系统的预定餐厅功能

CREATE TABLE restaurants (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(255) NOT NULL,
    address VARCHAR(255) NOT NULL,
    capacity INT NOT NULL,
    available_time_start TIME NOT NULL,
    available_time_end TIME NOT NULL
);

CREATE TABLE reservations (
    id INT PRIMARY KEY AUTO_INCREMENT,
    restaurant_id INT NOT NULL,
    guest_name VARCHAR(255) NOT NULL,
    reservation_time DATETIME NOT NULL,
    FOREIGN KEY (restaurant_id) REFERENCES restaurants(id)
);

type Restaurant struct {
    ID               int
    Name             string
    Address          string
    Capacity         int
    AvailableTimeStart time.Time
    AvailableTimeEnd   time.Time
}

type Reservation struct {
    ID               int
    RestaurantID     int
    GuestName        string
    ReservationTime  time.Time
}

var db *sql.DB

func main() {
    var err error
    db, err = sql.Open("mysql", "root:passWord@tcp(localhost:3306)/restaurant")
    if err != nil {
        log.Fatal(err)
    }
    defer db.Close()

    // 运行Http服务器
    http.HandleFunc("/restaurants", getRestaurantsHandler)
    http.HandleFunc("/available-restaurants", getAvailableRestaurantsHandler)
    http.HandleFunc("/reservations", getReservationsHandler)
    http.HandleFunc("/reserve", addReservationHandler)

    log.Fatal(http.ListenAndServe(":8080", nil))
}

func getRestaurantsHandler(w http.ResponseWriter, r *http.Request) {
    rows, err := db.Query("SELECT * FROM restaurants")
    if err != nil {
        log.Fatal(err)
    }
    defer rows.Close()

    var restaurants []Restaurant
    for rows.Next() {
        var restaurant Restaurant
        err := rows.Scan(&restaurant.ID, &restaurant.Name, &restaurant.Address, &restaurant.Capacity, &restaurant.AvailableTimeStart, &restaurant.AvailableTimeEnd)
        if err != nil {
            log.Fatal(err)
        }
        restaurants = append(restaurants, restaurant)
    }

    JSON.NewEncoder(w).Encode(restaurants)
}

func getAvailableRestaurantsHandler(w http.ResponseWriter, r *http.Request) {
    currentTime := time.Now()
    rows, err := db.Query("SELECT * FROM restaurants WHERE available_time_start <= ? AND available_time_end >= ?", currentTime, currentTime)
    if err != nil {
        log.Fatal(err)
    }
    defer rows.Close()

    var restaurants []Restaurant
    for rows.Next() {
        var restaurant Restaurant
        err := rows.Scan(&restaurant.ID, &restaurant.Name, &restaurant.Address, &restaurant.Capacity, &restaurant.AvailableTimeStart, &restaurant.AvailableTimeEnd)
        if err != nil {
            log.Fatal(err)
        }
        restaurants = append(restaurants, restaurant)
    }

    json.NewEncoder(w).Encode(restaurants)
}

func getReservationsHandler(w http.ResponseWriter, r *http.Request) {
    rows, err := db.Query("SELECT * FROM reservations")
    if err != nil {
        log.Fatal(err)
    }
    defer rows.Close()

    var reservations []Reservation
    for rows.Next() {
        var reservation Reservation
        err := rows.Scan(&reservation.ID, &reservation.RestaurantID, &reservation.GuestName, &reservation.ReservationTime)
        if err != nil {
            log.Fatal(err)
        }
        reservations = append(reservations, reservation)
    }

    json.NewEncoder(w).Encode(reservations)
}

func addReservationHandler(w http.ResponseWriter, r *http.Request) {
    var reservation Reservation
    err := json.NewDecoder(r.Body).Decode(&reservation)
    if err != nil {
        http.Error(w, err.Error(), http.StatusBadRequest)
        return
    }

    stmt, err := db.Prepare("INSERT INTO reservations (restaurant_id, guest_name, reservation_time) VALUES (?, ?, ?)")
    if err != nil {
        log.Fatal(err)
    }
    defer stmt.Close()

    _, err = stmt.Exec(reservation.RestaurantID, reservation.GuestName, reservation.ReservationTime)
    if err != nil {
        log.Fatal(err)
    }

    w.WriteHeader(http.StatusOK)
}