JPA枚举继承

Question

#Interface
interface BillCategory

#Enum 1
public enum GroceryPurchase implements BillCategory {
  VEGAN,  
  VEGETARIAN,
  PESCITARIAN,
  FLEXITARIAN, 
  OMNIVORE


#Enum 2
enum ElectronicPurchase implements BillCategory{ 
 SMARTPHONE, HARDWARE, SOFTWARE }

private BillCategory billCategory;

Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.MappingException: Could not determine type for: net.wizypay.wizypay.bill.model.BillCategory, at table: bill_entity, for columns: [org.hibernate.mapping.Column(bill_category)]

Answer 1

当然，我不知道Smartphone怎么不是Hardware，但是可以。以下是我将如何做到这一点（不确定我是否丢弃了您现在实际需要的东西）。使BillCategory成为枚举。添加私有字段PurchaseType（这也可以是另一个枚举，包含GroceryPurche或ElectronicPurche)和Category（这是字符串，与枚举名称匹配）。这应该可以解决Hibernate的问题。

说明我的意思的代码：

enum BillCategory {

    VEGAN("VEGAN", PurchaseType.GroceryPurchase), 
    VEGETARIAN("VEGETARIAN",PurchaseType.GroceryPurchase),
    SMARTPHONE("SMARTPHONE", PurchaseType.ElectronicPurchase);

    private String category;
    private PurchaseType type;

    BillCategory(String category, PurchaseType type) {
        this.category = category;
        this.type = type;
    }

    public String getCategory() {
        return category;
    }

    public void setCategory(String category) {
        this.category = category;
    }

    public PurchaseType getType() {
        return type;
    }

    public void setType(PurchaseType type) {
        this.type = type;
    }

}

enum PurchaseType {
    ElectronicPurchase, GroceryPurchase;
}

然后，您还应该使用@enumerated(enumtype.ordinal)或其他一些enumtype注释实体类中的private BillCategory；，这取决于您希望将其保存在数据库中的方式