这是我第一次开发 Java 应用程序并立即遇到问题。现在我有一个如下的 SQL 查询:
Select PD.* From product PD
join Stock SP on PD.id = SP.product_id
join storage SR on SR.id = SP.storage_id
join status ST on ST.storage_id = SR.id
where ST.id ='1qa7n234i'
我的实体:
public class Product extends MainEntity {
public Product(){}
public void setAtcKey(String pAtcKey) {
atcKey = pAtcKey;
}
}
public class StockPosition extends MainEntity {
public StockPosition(){}
@XmlIDREF
public Product getProduct() {
return product;
}
public void setProduct(Product pProduct) {
product = pProduct;
}
@XmlIDREF
public Storage getStorage() {
return storage;
}
public void setStorage(Storage pStorage) {
storage = pStorage;
}
}
public class Storage extends MainEntity {
public Storage(){}
@XmlTransient
public Station getStation() {
return station;
}
public void setStation(Station pStation) {
station = pStation;
}
}
public class Status extends MainEntity {
public Status(){}
}
所以我将它转换为 CriteriaQuery,如:
CriteriaBuilder cb = getCriteriaBuilder();
CriteriaQuery<Product> query = cb.createQuery(Product.class);
Root<Product> product = query.from(Product.class);
Join<StockPosition, Product> sp = product.join(StockPosition_.product);
但是我收到一条错误消息,例如The method join(SingularAttribute<? super Product,Y>) in the type From<Product,Product> is not applicable for the arguments (SingularAttribute<StockPosition,Product>)
?这个消息对我来说很奇怪(因为我是新手)。谢谢