休眠如何保存多對一

Question

我有兩個實體Equipement和Company這樣的：

public class Equipement{ 
    String type ; 
    Company company ; 

    @ManyToOne(cascade = CascadeType.ALL) 
    public Company getCompany(){ 
    return this.company ; 
    } 
} 

public class Company{ 
    // fields getters setters .. 
} 

每個Equipement從Company買的，我需要創建Company，然後將其注入到Equipement

Session session = SessionFactory.openSession() ; 
Transaction tx = session.beginTransaction() ; 

Equipement equipement = new Equipement() ; 
Company company = new company() ; 
equipement.setCompany(company) ; 
session.save(equipement) ; 

tx.commit() ; 
session.close() ; 

並給我一個例外

TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: org.marsamaroc.mmapp.domain.Company 

Answer 1

嘗試

public class Company 
{ 
    @OneToMany(cascade = CascadeType.ALL) 
    public Set<Equipement> getEquipements() { ... } 
} 

和

... 
Session session = SessionFactory.openSession() ; 
Transaction tx = session.beginTransaction() ; 

Equipement equipement = new Equipement() ; 
Company company = new company() ; 
equipement.setCompany(company) ; 

// Save should cascade (i.e. "equipment" should be saved too). 
session.save(company) ; 

tx.commit() ; 
session.close() ; 
... 

順便說一下，在英語中，它的 「裝備」，沒有額外的 'E'（如果你關心！）。