Question

这样，“雇员”应该能够看到数据库中的所有订单。而那些不是雇员的人必须能够根据其userId查看自己的订单。

问题只是我的executeQuery出错了。

错误提示：

变量p可能尚未初始化

例如，如果我输入PreparedStatement p = null，它会告诉我第一个SQL是“ NullPointerException ”

ArrayList<Order> orders = new ArrayList<>(); // tom collection.

    try {
        Connection cc = Connector.connection();
        String SQL;
        PreparedStatement p;
        if("employee".equals(user.getRole()))
        {
            SQL = "SELECT * FROM orders ORDER BY orderId DESC";
        }
        else
        {
            SQL = "SELECT * FROM orders WHERE userId = ? ORDER BY orderId DESC";
            p = cc.prepareStatement(SQL);
            p.setInt(1, user.getId());
        }



        try(ResultSet rs = p.executeQuery();)
        {
            while(rs.next())
            {

                orders.add(new Order(
                            rs.getInt("orderId"), 
                            user, 
                            rs.getInt("length"), 
                            rs.getInt("width"), 
                            rs.getInt("height"), 
                            rs.getDate("date"), 
                            rs.getDate("shippingDate"), 
                            rs.getBoolean("shipped")));
            }
        }

        return orders;
    }
    catch(ClassNotFoundException | SQLException ex){
        throw new Other(ex.getMessage());
    }

我有一个拥有这些值的构造函数。

public Order(int orderid, User user, int length, int width, int height, Date dt, Date shippingDate, boolean shipped) {
    this.OrderId = orderid;
    this.user = user;
    this.length = length;
    this.width = width;
    this.height = height;
    this.dt = dt;
    this.shippingDate = shippingDate;
    this.shipped = shipped;
}

作为起点，我仅使用OrderID，length，width，height，date，shippingDate和{{1 }}。

Answer 1

您还需要在PrepareStatement p块中if（就像在else中一样）。喜欢，

PreparedStatement p;
if("employee".equals(user.getRole())) {
    SQL = "SELECT * FROM orders ORDER BY orderId DESC";
    // Add this...
    p = cc.prepareStatement(SQL);
} else {
    SQL = "SELECT * FROM orders WHERE userId = ? ORDER BY orderId DESC";
    // Just like here
    p = cc.prepareStatement(SQL);
    p.setInt(1, user.getId());
}

而那些不是雇员的人-如何确保它在executeQuery中不会出错？

1 个答案: