Java org.hibernate.LazyInitializationException关联集合

我有两个模型类，它们由多对多关系关联：

@Entity
@XmlRootElement
@DynamicInsert (value = true)
@DynamicUpdate (value = true)
public class Matchs {

    @Id @GeneratedValue
    private Long matchId;
    private int size;
    private Date begins;
    private Date cutOff;
    private BigDecimal buyIn;

    @ManyToMany
    private List<Users> users;
}

@Entity
@XmlRootElement
@DynamicInsert (value = true)
@DynamicUpdate (value = true)
public class Users {

    @Id
    private String username;
    private String lastName,firstName,password,email;

    private Date dateOfBirth;

    @ManyToMany
    private List<Matchs> matchs;
}

但这会引发以下异常：

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.kyrogaming.models.Users.matchs, could not initialize proxy - no Session
at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:566)
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:186)
at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:545)
at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:124)
at org.hibernate.collection.internal.PersistentBag.iterator(PersistentBag.java:266)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:95)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:89)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:195)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:96)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:89)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:195)
at com.google.gson.Gson.toJson(Gson.java:593)
at com.google.gson.Gson.toJson(Gson.java:572)
at com.google.gson.Gson.toJson(Gson.java:527)
at com.google.gson.Gson.toJson(Gson.java:507)
at com.kyrogaming.services.MatchService.getMatchById(MatchService.java:77)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1469)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1400)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:699)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:565)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:479)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:521)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1031)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:406)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:186)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:965)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
at org.eclipse.jetty.server.Server.handle(Server.java:349)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:449)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:910)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:634)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:230)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:76)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:609)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:45)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:599)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:534)

我哪里出错了，因为我真的不知道为什么用户代理对象没有初始化

这是一个抽象类，由所有Hibernate DAO类扩展，并包含与Hibernate交互的方法

public abstract class AbstractHibernate <T>{
private SessionFactory sessionFactory;

private Session session;

@Inject
public void setSessionFactory (SessionFactory sessionFactory)
{
    this.sessionFactory = sessionFactory;
}



protected Session getSession () 
{
    if (sessionFactory == null)
        throw new NullPointerException("SessionFactory null ");
    if (session == null)
    {
        session = sessionFactory.openSession();
        return session; 
    }
    return session;
}


public void begin ()
{
    getSession().beginTransaction();
}



public void commit () throws HibernateException
{
    getSession().getTransaction().commit();
}


public void rollback ()
{
    getSession().getTransaction().rollback();
}


protected void close ()
{
    if (getSession () != null)
    {
        session.close();
        session = null;
    }
}

公共抽象类AbstractHibernate{
私人会话工厂会话工厂；
非公开会议；
@注入
public void setSessionFactory（SessionFactory SessionFactory）
{
this.sessionFactory=sessionFactory；
}
受保护会话getSession（）
{
if（sessionFactory==null）
抛出新的NullPointerException（“SessionFactory null”）；
if（会话==null）
{
session=sessionFactory.openSession（）；
返回会议；
}
返回会议；
}
公共无效开始（）
{
getSession（）.beginTransaction（）；
}
public void commit（）引发HibernateeException
{
getSession（）.getTransaction（）.commit（）；
}
公共无效回滚（）
{
getSession（）.getTransaction（）.rollback（）；
}
受保护的无效关闭（）
{
if（getSession（）！=null）
{
session.close（）；
会话=空；
}
}

我假设

.entity（new GsonBuilder（）.setPrettyPrinting（）.create（）.toJson（match））

中的代码正在调用

User.getMatchs（）

，但是因为您已经关闭了会话，它不能延迟加载它们。您应该立即加载它们，或者在关闭会话之前加载它们。

我假设

entity中的代码（新的GsonBuilder（）.setPrettyPrinting（）.create（）.toJson（match））

正在调用

User.getMatchs（）

但由于您已关闭会话，它无法延迟加载。您应该立即加载它们，或者在关闭会话之前加载它们。

您是否有

.hbm

文件？否，我正在使用annotationsHow处理您的事务吗？当您在关闭tx后尝试加载收藏时会发生此错误。哦！抱歉。我知道解决方案您必须在映射类标记中添加属性

lazy=false

的xml文件。我有一个抽象类，所有Hibernate DAO类都扩展该类，其中包含与Hibernate api交互的方法。我将把它添加到问题中。您有

.hbm

文件吗？没有，我正在使用annotationsHow处理事务吗？这是错误发生在关闭tx.ohh后尝试加载集合时。抱歉。我知道xml文件的解决方案，您必须在映射类标记中添加属性

lazy=false

。我有一个抽象类，所有Hibernate DAO类都扩展该类，该类包含与Hibernate api交互的方法。我将它添加到问题中t当我在findMatchWithUsers方法中调用Hibernate.initialize（match.getUser（））时，当我调用matchDAO.findMatchWithUsers（）时，您需要对user.getMatchs（）使用相同的方法关键是，如果你盲目地这样做，这将与急于加载相同，因此我建议在你的服务方法中执行

toJson

，以便能够加载真正需要的内容。好的。问题正如你建议的那样，我需要初始化user.getMatchs（），我在调用Hibernate.initialize（match.getUser（））时就是这么做的在调用matchDAO.findMatchWithUsers（）时的findMatchWithUsers方法中，需要对user.getMatchs（）使用相同的方法关键是，如果您盲目地这样做，这将与急于加载相同，因此我建议在您的服务方法中执行

toJson

，以便能够加载真正需要的内容。好的。问题正如您所建议的，我需要初始化user.getMatchs（）

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.kyrogaming.models.Users.matchs, could not initialize proxy - no Session
at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:566)
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:186)
at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:545)
at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:124)
at org.hibernate.collection.internal.PersistentBag.iterator(PersistentBag.java:266)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:95)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:89)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:195)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:96)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:68)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.write(ReflectiveTypeAdapterFactory.java:89)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.write(ReflectiveTypeAdapterFactory.java:195)
at com.google.gson.Gson.toJson(Gson.java:593)
at com.google.gson.Gson.toJson(Gson.java:572)
at com.google.gson.Gson.toJson(Gson.java:527)
at com.google.gson.Gson.toJson(Gson.java:507)
at com.kyrogaming.services.MatchService.getMatchById(MatchService.java:77)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1469)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1400)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:699)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:565)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:479)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:521)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1031)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:406)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:186)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:965)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
at org.eclipse.jetty.server.Server.handle(Server.java:349)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:449)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:910)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:634)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:230)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:76)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:609)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:45)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:599)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:534)

public abstract class AbstractHibernate <T>{
private SessionFactory sessionFactory;

private Session session;

@Inject
public void setSessionFactory (SessionFactory sessionFactory)
{
    this.sessionFactory = sessionFactory;
}



protected Session getSession () 
{
    if (sessionFactory == null)
        throw new NullPointerException("SessionFactory null ");
    if (session == null)
    {
        session = sessionFactory.openSession();
        return session; 
    }
    return session;
}


public void begin ()
{
    getSession().beginTransaction();
}



public void commit () throws HibernateException
{
    getSession().getTransaction().commit();
}


public void rollback ()
{
    getSession().getTransaction().rollback();
}


protected void close ()
{
    if (getSession () != null)
    {
        session.close();
        session = null;
    }
}