@OneToMany(mappedBy="order",fetch=FetchType.EAGER,cascade={CascadeType.ALL})
private List<OrderItem> orderItem;
order
该属性的值是“多”方class里的“一”方的变量名
OrderItem里边Order的变量名order
@OneToMany(mappedBy="order",fetch=FetchType.EAGER,cascade={CascadeType.ALL})
private List<OrderItem> orderItem;
order