我试图建立一个多基于这个例子与JPA许多双向关系:http://www.mkyong.com/hibernate/hibernate-many-to-many-example-join-table-extra-column-annotation/多对多的关系:org.hibernate.MappingException:无法确定类型:java.util.Set中
我米得到一个
org.hibernate.MappingException:无法确定类型:java.util.Set中,在表中:T_ITEM,对于列:[org.hibernate.mapping.Column(itemHikes)]
如果有人能帮助我,那就是下面的源代码:
类物品
@Entity
@Table(name="T_ITEM")
public class Item implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private Long id;
private Set<ItemHike> itemHikes = new HashSet<ItemHike>(0);
@OneToMany(fetch = FetchType.LAZY, mappedBy = "pk.item", cascade=CascadeType.ALL)
public Set<ItemHike> getItemHikes() {
return this.itemHikes;
}
public void setItemHikes(Set<ItemHike> itemHikes) {
this.itemHikes = itemHikes;
}
}
类远足
@Entity
@Table(name="T_HIKE")
public class Hike implements Serializable {
private static final long serialVersionUID = 1L;
@Id
private Long id;
private List<ItemHike> itemHikes = new ArrayList<ItemHike>(0);
@OneToMany(fetch = FetchType.LAZY, mappedBy = "pk.hike", cascade=CascadeType.ALL)
public List<ItemHike> getItemHikes() {
return this.itemHikes;
}
public void setItemHikes(List<ItemHike> itemHikes) {
this.itemHikes = itemHikes;
}
}
类ItemHike
@Entity
@Table(name="T_ITEM_HIKE")
@AssociationOverrides({
@AssociationOverride(name = "pk.item",
joinColumns = @JoinColumn(name = "iditem")),
@AssociationOverride(name = "pk.hike",
joinColumns = @JoinColumn(name = "idlist")) })
public class ItemHike implements Serializable {
private static final long serialVersionUID = 1L;
@EmbeddedId
private ItemHikePK pk;
private int quantity;
//bi-directional many-to-one association to THike
@Transient
public Item getItem() {
return getPk().getItem();
}
public void setItem(Item item) {
getPk().setItem(item);
}
@Transient
public Hike getHike() {
return getPk().getHike();
}
public void setHike(Hike hike) {
getPk().setHike(hike);
}
public ItemHike() {
}
public ItemHikePK getPk() {
return this.pk;
}
public void setPk(ItemHikePK pk) {
this.pk = pk;
}
public int getQuantity() {
return this.quantity;
}
public void setQuantity(int quantity) {
this.quantity = quantity;
}
}
类ItemHikePk
@Embeddable
public class ItemHikePK implements Serializable {
//default serial version id, required for serializable classes.
private static final long serialVersionUID = 1L;
private Item item;
private Hike hike;
@ManyToOne
public Item getItem() {
return item;
}
public void setItem(Item item) {
this.item = item;
}
@ManyToOne
public Hike getHike() {
return hike;
}
public void setHike(Hike hike) {
this.hike = hike;
}
}
谢谢您的回答,我没有找到stakoverflow了类似的回答。它正在工作。但在运行时,我得到一个com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException:'字段列表'中的未知列'itemhikes1_.item'。其实,这个领域提到的是成语,而不是'项目'。它由pk.item引用。 – user1260928 2014-10-31 21:36:07
你说你的MySql表中的字段是'成语',那么当你在'@AssociationOverride'中声明'@JoinColumn'时,你应该输入正确的字段名,现在你有'@JoinColumn(name =“iditem “)',你应该有:'@JoinColumn(name =”idiom“)'。 – 2014-11-01 07:57:03
对不起,我的平板电脑将iditem这个词变成了成语,我没有看到它。该领域是iditem。这就是为什么我不明白为什么它不能看到这个领域。 – user1260928 2014-11-01 09:22:36