Hibernate學習筆記(一)——插入一條帶有外鍵的數據

存在兩張表，它們是多對一的關係

@Entity
@Table(name = "goods", schema = "weitao")
public class Goods {

    private int id;
    private String name;
    private Double price;
    private Integer number;
    private String description;
    private TinyCategory categoryId;
}

@Entity
@Table(name = "shopping_entry", schema = "weitao")
public class ShoppingEntry {

    private int id;
    private int number;
    private Goods goods;

    @ManyToOne(targetEntity = Goods.class)
    @JoinColumn(name = "goods_id", referencedColumnName = "id")
    public Goods getGoods() {
        return goods;
    }

    public void setGoods(Goods goods) {
        this.goods = goods;
    }

}

Goods表中有各類商品，想要插入ShoppingEntry的同時使外鍵生效，但是session.save(entry)存儲時不能直接對外間進行賦值

解決方法：

Goods goods = (Goods) session.load(Goods.class, Integer.valueOf(newEntry.get("goodsId").toString()));
ShoppingEntry entry = new ShoppingEntry();
entry.setNumber(Integer.valueOf(newEntry.get("number").toString()));
entry.setGoods(goods);
session.save(entry);