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액션 클래스를 통해이 데이터베이스 루틴에 액세스하려고하는 두 개의 JSP가 있습니다. 내가 아무 try/catch/finally 루틴 및 커밋 트랜잭션 또는 세션 닫을 때 나는 결과를 얻을 수 있지만 처음에만. 다음 jsp가 그들에게 접근을 시도 할 때 나는 세션을 닫지 않았기 때문에 nested transactions not supported을 얻는다.Hibernate LazyLoading no session
session.close()과 같은 세션을 닫으면 session was already closed error이됩니다. HibernateUtil.close()을 사용할 때 (내가 threadLocale을 닫아야한다는 것을 알기 때문에) 나는 LazyInitializationException: could not initialize proxy - no Session을 얻습니다.
첫 번째 DB 히트 이후에 목록을 저장/유지해야합니까? 또는 게으른로드에서 열심히로드로 변경 하시겠습니까? 그들에 대해 읽은 후에도, 내가이 인스턴스에 어떻게 적용되는지 완전히 이해하지 못하고 정확하게해야한다면 eager 로딩을 지정하는 방법을 정확히 알지 못합니다. 이 주석 사용법을 보았습니다 fetch = FetchType.LAZY 그러나 매핑 태그를 사용하여 열심히 지정하려면 어떻게해야합니까?
DAO 거래
public List<Flights> getflights(String departure, String destination)
{
this.session = HibernateUtil.getSessionFactory().getCurrentSession();
List<Flights> flist = null;
if(session ==null){session = HibernateUtil.getSessionFactory().getCurrentSession();}
Transaction tx = session.beginTransaction();
try
{
String hql = "from Flights as f Where f.destinationsByDepartureCode = :departureCode AND f.destinationsByDestinationCode = :destinationCode";
Query q = session.createQuery(hql);
q.setParameter("departureCode", departure);
q.setParameter("destinationCode", destination);
flist = (List<Flights>) q.list();
tx.commit();
tx = null;
}
catch (Exception e)
{
tx.rollback();
e.printStackTrace();
}
finally{
// session.close();
HibernateUtil.closeSession(); // diff to above. this closes threadlocale.
}
return flist;
}
항공편 매핑
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- Generated 07/05/2014 11:35:38 PM by Hibernate Tools 3.6.0 -->
<hibernate-mapping>
<class catalog="seng3150" name="model.hibernate.Flights" table="flights">
<id name="flightid" type="java.lang.Integer">
<column name="flightid"/>
<generator class="identity"/>
</id>
<many-to-one class="model.hibernate.Destinations" fetch="select" name="destinationsByStopOverCode">
<column length="3" name="StopOverCode"/>
</many-to-one>
<many-to-one class="model.hibernate.Destinations" fetch="select" name="destinationsByDestinationCode">
<column length="3" name="DestinationCode" not-null="true"/>
</many-to-one>
<many-to-one class="model.hibernate.Airlines" fetch="select" name="airlines">
<column length="2" name="AirlineCode" not-null="true"/>
</many-to-one>
<many-to-one class="model.hibernate.Destinations" fetch="select" name="destinationsByDepartureCode">
<column length="3" name="DepartureCode" not-null="true"/>
</many-to-one>
<many-to-one class="model.hibernate.Planetype" fetch="select" name="planetype">
<column length="20" name="PlaneCode" not-null="true"/>
</many-to-one>
<property name="flightNumber" type="string">
<column length="6" name="FlightNumber" not-null="true"/>
</property>
<property name="departureTime" type="timestamp">
<column length="19" name="DepartureTime" not-null="true"/>
</property>
<property name="arrivalTimeStopOver" type="timestamp">
<column length="19" name="ArrivalTimeStopOver"/>
</property>
<property name="departureTimeStopOver" type="timestamp">
<column length="19" name="DepartureTimeStopOver"/>
</property>
<property name="arrivalTime" type="timestamp">
<column length="19" name="ArrivalTime" not-null="true"/>
</property>
<property name="duration" type="int">
<column name="Duration" not-null="true"/>
</property>
<property name="durationSecondLeg" type="java.lang.Integer">
<column name="DurationSecondLeg"/>
</property>
<set fetch="select" inverse="true" lazy="true" name="bookingses" table="bookings">
<key>
<column name="flightid" not-null="true"/>
</key>
<one-to-many class="model.hibernate.Bookings"/>
</set>
</class>
</hibernate-mapping>