[英](org.hibernate.LazyInitializationException) org.hibernate.LazyInitializationException: could not initialize proxy - no Session
[英]Hibernate org.hibernate.LazyInitializationException: could not initialize
我有两节课:
Etudiant并支付
在数据库中,表Etudiant
具有表Pays
的外键。
在我的代码中,我有这样的东西:
List<Etudiant> listEtudiants = (List<Etudiant>) etudiantService.getAll();
for(Etudiant etudiant : listEtudiants) {
if(((JTextField)arg0.getSource()).getText().equals(etudiant.getNom())){
System.out.println(etudiant.getPays().getNom());
}
}
但是,当我运行这段代码时,它失败并出现以下异常:
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
在行中:
System.out.println(etudiant.getPays().getNom());
映射学生:
<hibernate-mapping>
<class name="tp.ihm.domain.Etudiant" table="etudiant" schema="public" optimistic-lock="version">
<id name="numInsc" type="java.lang.Long">
<column name="num_insc" />
<generator class="assigned" />
</id>
<many-to-one name="pays" class="tp.ihm.domain.Pays" fetch="select">
<column name="pays" not-null="true" />
</many-to-one>
<property name="nom" type="string">
<column name="nom" length="50" not-null="true" />
</property>
<property name="prenom" type="string">
<column name="prenom" length="50" not-null="true" />
</property>
</class>
</hibernate-mapping>
薪酬映射:
<hibernate-mapping>
<class name="tp.ihm.domain.Pays" table="pays" schema="public" optimistic-lock="version">
<id name="id" type="java.lang.Long">
<column name="id" />
<generator class="assigned" />
</id>
<property name="nom" type="string">
<column name="nom" length="45" not-null="true" />
</property>
<set name="etudiants" table="etudiant" inverse="true" lazy="true" fetch="select">
<key>
<column name="pays" not-null="true" />
</key>
<one-to-many class="tp.ihm.domain.Etudiant" />
</set>
</class>
</hibernate-mapping>
我尝试删除Pays
映射中的fetch属性,然后将其值更改为渴望,但没有任何效果。
有人可以帮我吗?
这是getAll
方法的代码:
public List getAll() throws EntityNotFoundException {
// Get the current session
Session s = getSession();
List list = null;
// If the BLL layer started a transaction
// In this case it is the BLL layer that manages the session and transaction
if (anActiveTransactionExist(s)) {
list = s.createCriteria(Etudiant).list();
} else {
LOGGER.debug("DAO initialize its own transaction");
Transaction tx = null;
try {
// Starts a transaction locally
tx = s.beginTransaction();
list = s.createCriteria(boClass).list();
tx.commit();
} catch (RuntimeException ex) {
// Cancel the transaction if there is a problem
handleDaoOpError(tx, ex);
} finally {
closeSession(s);
}
}
if (list == null || list.size() == 0)
throw new EntityNotFoundException();
return list;
}
您需要将Etudiant
的映射从fetch=select
更改为fetch=join
fetch-“join” = Disable the lazy loading, always load all the collections and entities.
fetch-“select” (default) = Lazy load all the collections and entities.
<many-to-one name="pays" class="tp.ihm.domain.Pays" fetch="join">
<column name="pays" not-null="true" />
</many-to-one>
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