一个订单的案例

一个订单应该包括一个订单项,和一个订单
订单项的商品id关联商品表,订单项的订单id关联订单表
一个订单项应该包括:订单项ID,商品ID,订单ID,数量和小计
一个订单表应该包括:订单ID,订单时间,订单总金,收货人,电话,地址,状态,用户ID

一个订单项的实体:

class OrderItem {
    //订单项ID
    private String itemid;
    //数量
    private Integer count;
    //小计
    private Double subtotal;
    //订单项id直接由订单实体对象代替
    private Order order;
    //商品ID也由商品实体对象代替
    private Product product;
    public String getItemid() {
        return itemid;
    }
    public void setItemid(String itemid) {
        this.itemid = itemid;
    }
    public Integer getCount() {
        return count;
    }
    public void setCount(Integer count) {
        this.count = count;
    }
    public Double getSubtotal() {
        return subtotal;
    }
    public void setSubtotal(Double subtotal) {
        this.subtotal = subtotal;
    }
    public Product getProduct() {
        return product;
    }
    public void setProduct(Product product) {
        this.product = product;
    }
    public Order getOrder() {
        return order;
    }
    public void setOrder(Order order) {
        this.order = order;
    }
}

一个订单的实体:

class Order{
    //订单的ID
    private String oid;
    //订单的创建时间
    private Date ordertime;
    //订单的总金额
    private Double total;
    //订单的状态
    private Integer state; // 1:未付款   2:已经付款,未发货. 3:已结发货,没有确认收货.  4:已结确认收货,订单结束.
    //订单的地址
    private String address;
    //订单的收件人
    private String name;
    //订单的收件人电话
    private String telephone;
    //订单关联的用户信息id,由用户实体对象代替
    private User user;
    //订单关联的订单项的集合
    private List<OrderItem> orderItems = new ArrayList<OrderItem>();
    public String getOid() {
        return oid;
    }

    public void setOid(String oid) {
        this.oid = oid;
    }

    public Date getOrdertime() {
        return ordertime;
    }

    public void setOrdertime(Date ordertime) {
        this.ordertime = ordertime;
    }

    public Double getTotal() {
        return total;
    }

    public void setTotal(Double total) {
        this.total = total;
    }

    public Integer getState() {
        return state;
    }

    public void setState(Integer state) {
        this.state = state;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getTelephone() {
        return telephone;
    }

    public void setTelephone(String telephone) {
        this.telephone = telephone;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public List<OrderItem> getOrderItems() {
        return orderItems;
    }

    public void setOrderItems(List<OrderItem> orderItems) {
        this.orderItems = orderItems;
    }
}

在用户点击提交订单的时候,需要清空购物车,跳转到一个servlet的saveCart()方法
在这个方法中要封装order和orderItem对象
下面是这个方法,省略service层和dao层

public String saveOrder(HttpServletRequest request,HttpServletResponse response) {
    //首先创建order实体对象
    Order order = new  order();
    //设置订单的编号,由uuid的工具类直接生成
    order.setOid(UUIDUtils.getUUID());
    //设置订单的生成时间
    order.setOrderTime(new Date());
    //设置付款状态
    order.setState(1);
    //首先获得购物车对象,
    Cart cart = (Cart) request.getSession().getAttribute("cart");
    //判断购物车是否为空
    if(cart == null) {
        request.setAttribute("msg", "购物车是空的!");
        return "/jsp/msg.jsp";
    }
    //设置总金额
    order.setTotal(cart.getTotal());
    //获得User对象
    User user = (User) request.getSession().getAttribute("existUser");
    //判断用户是否登录
    if(user == null) {
        request.setAttribute("msg", "您还没有登录!");
        return "/jsp/login.jsp";
    }
    //设置订单的客户
    order.setUser(user);
    
    //创建订单项的实体
    OrderItem orderItem = new OrderItem();
    //因为不确定一个订单中有多少个订单项,所以遍历为购物车中的购物项设置值
    for(CartItem cartItem:cart.getMap().values()) {
        //设置订单项id
        orderItem .setItemid(UUIDUtils.getUUID());
        //设置数量
        orderItem.setCount(cartItem.getCount());
        //设置小计
        orderItem.setSubtotal(cartItem.getSubtotal());
        //设置商品
        orderItem.setProduct(cartItem.getProduct());
        //设置订单
        orderItem.setOrder(order);
    }
    //调用业务层保存把order保存到数据库中
    OrderService os = new OrderServiceImpl();
    os.save(order);
    //订单一旦生成就清空购物车
    cart.clearCart();
    //把order保存到域对象然后转发
    request.setAttribute("order", order);
    return "/jsp/order_info.jsp";
}