failed to lazily initialize a collection of role:complexDataSets, could not initialize proxy - no Session

Question

Контекст:

<?xml version="1.0" encoding="UTF-8"?>
   <beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       
   xmlns:aop="http://www.springframework.org/schema/aop"
   xmlns:context="http://www.springframework.org/schema/context"
   xmlns:task="http://www.springframework.org/schema/task"
   xmlns:int="http://www.springframework.org/schema/integration"
   xmlns:int-ip="http://www.springframework.org/schema/integration/ip"
   xmlns:tx="http://www.springframework.org/schema/tx"
   xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
   http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration-2.2.xsd
      http://www.springframework.org/schema/integration/ip http://www.springframework.org/schema/integration/ip/spring-integration-ip-2.2.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd
        http://www.springframework.org/schema/beans
 http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">


<context:component-scan base-package="Main.*" />
<aop:aspectj-autoproxy />
<task:annotation-driven/>
<tx:annotation-driven transaction-manager="transactionManager" />

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://localhost:3306/db_example" />
    <property name="username" value="root" />
    <property name="password" value="tully" />
</bean>

<!-- server beans -->

<bean id="byteArrayCrLfSerializer" class="org.springframework.integration.ip.tcp.serializer.ByteArrayCrLfSerializer" />

<int-ip:tcp-connection-factory id="tcpServerFactory"
                               type="server"
                               port="23234"
                               single-use="false"
                               serializer="byteArrayCrLfSerializer"
                               deserializer="byteArrayCrLfSerializer"
/>

<int:channel id="serverIn" />

<int:channel id="serverOut" />

<int-ip:tcp-inbound-channel-adapter channel="serverIn" connection-factory="tcpServerFactory"/>
<int-ip:tcp-outbound-channel-adapter channel="serverOut" connection-factory="tcpServerFactory"/>

<int:service-activator ref="senderService" method="send" input-channel="serverIn"/>

<!-- Hibernate -->
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="packagesToScan" value="org.baeldung.spring.persistence.model" />
    <property name="annotatedClasses">
        <list>
            <value>Main.database.dataSet.ComplexDataSet</value>
            <value>Main.database.dataSet.CameraDataSet</value>
            <value>Main.database.dataSet.CommunityDataSet</value>
            <value>Main.database.dataSet.JournalDataSet</value>
            <value>Main.database.dataSet.RegionDataSet</value>
            <value>Main.database.dataSet.SpotDataSet</value>
            <value>Main.database.dataSet.TypeDataSet</value>
            <value>Main.database.dataSet.VersionDataSet</value>
            <value>Main.database.dataSet.CountThreadDataSet</value>
        </list>
    </property>

    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.hbm2ddl.auto">validate</prop>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
            <prop key="hibernate.show_sql">false</prop>
        </props>
    </property>

</bean>

<bean id="transactionManager"
      class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

SpotDataSet

@Entity
@Table(name = "spot")
public class SpotDataSet implements Serializable {
@Id
@Column(name = "spot_id")
@GeneratedValue
private long spot_id;
@Column(name = "maps")
private String maps;
@ManyToOne(cascade=CascadeType.ALL)
@JoinColumn(name="region_id")
private RegionDataSet region;
@OneToMany(fetch = FetchType.LAZY,mappedBy = "spot")
private Set<ComplexDataSet> complexDataSets;

    ......
}

ComplexDataSet

@Entity
@Table(name = "complex")
public class ComplexDataSet implements Complex,Serializable {
@Id
@Column(name = "id")
@GeneratedValue
private long id;
@ManyToOne(cascade = {CascadeType.ALL})
@JoinColumn(name="spot_id")
private SpotDataSet spot;
@Column(name = "priority")
private int priority;
@Column(name = "type")
private int type;
@Column(name = "ip")
private String ip;
@ManyToOne(cascade = {CascadeType.ALL})
@JoinColumn(name = "version_id")
private VersionDataSet version;
@ManyToOne(cascade = {CascadeType.ALL})
@JoinColumn(name="community_id")
private CommunityDataSet community;
@OneToMany(fetch = FetchType.LAZY,mappedBy = "complex")
private Set<CameraDataSet> cameraDataSets;

 .....
}

DBService

@Transactional
    public List<SpotDataSet> getAllSpotDataSet(){
    Session session = sessionFactory.getCurrentSession();
    MySqlDAO dao = new MySqlDAO(session);
    return dao.getAllSpotDataSet();
}

DAO

public List<SpotDataSet> getAllSpotDataSet(){
    Criteria criteria=session.createCriteria(SpotDataSet.class);
    return (List<SpotDataSet>) criteria.list();
}

Main

 ApplicationContext ctx=new ClassPathXmlApplicationContext("spring-config.xml");
    DBService dbService=ctx.getBean(DBService.class);
    List<SpotDataSet> spotDataSets=dbService.getAllSpotDataSet();
    System.out.println(spotDataSets.get(0).getComplexDataSets().size());

Error

 Exception in thread "main" org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: Main.database.dataSet.SpotDataSet.complexDataSets, could not initialize proxy - no Session
at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:575)
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:214)
at org.hibernate.collection.internal.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:155)
at org.hibernate.collection.internal.PersistentSet.size(PersistentSet.java:160)

Answer 1

hibernate правильно ругается, т.к. не прогружены Set<ComplexDataSet> complexDataSets, попробуйте прогрузить их вот таким запросом:

DAO

public List<SpotDataSet> getAllSpotDataSet(){
    Criteria criteria=session.createCriteria(SpotDataSet.class)
    criteria.setFetchMode("complexDataSets", FetchMode.EAGER);//прогружаем
    criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
    return (List<SpotDataSet>) criteria.list();
}