Cannot fetch LAZY - JPA

2019-06-27 19:43发布

站内问答 / Java
1408 1 5

I want to do LAZY loading in a OneToMany Relation in JPA.

The Problem is, that when i want to acces the LAZY loaded Attribute i get a exception. I know that i have to be in a Transaction when trying to access the attribute. But it seems like the Transaction is not open. This is the exception:

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: de.recipemanager.recipe.data.Recipe.ingredients, 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 de.recipemanager.recipe.web.IngredientDTOList.<init>(IngredientDTOList.java:27)
        at de.recipemanager.recipe.web.RecipeDTO.<init>(RecipeDTO.java:28)
        at de.recipemanager.recipe.web.RecipeDTOServiceImpl.get(RecipeDTOServiceImpl.java:22)
        at de.recipemanager.recipe.web.RecipeController.get(RecipeController.java:32)
        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:606)
        at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:735)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:594)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1366)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:150)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:201)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
        at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
        at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
        at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1337)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:484)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
        at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:233)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1065)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:413)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:192)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:999)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
        at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:250)
        at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
        at org.eclipse.jetty.server.Server.handle(Server.java:351)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:454)
        at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:890)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:944)
        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:77)
        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)
        at java.lang.Thread.run(Thread.java:724)
2013-10-10 21:17:53.427:WARN:oejs.ServletHandler:/api/recipes/1
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: de.recipemanager.recipe.data.Recipe.ingredients, 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 de.recipemanager.recipe.web.IngredientDTOList.<init>(IngredientDTOList.java:27)
        at de.recipemanager.recipe.web.RecipeDTO.<init>(RecipeDTO.java:28)
        at de.recipemanager.recipe.web.RecipeDTOServiceImpl.get(RecipeDTOServiceImpl.java:22)
        at de.recipemanager.recipe.web.RecipeController.get(RecipeController.java:32)
        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:606)
        at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:219)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:735)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:594)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1366)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:150)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:201)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
        at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
        at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
        at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1337)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:484)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
        at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:233)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1065)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:413)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:192)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:999)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
        at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:250)
        at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
        at org.eclipse.jetty.server.Server.handle(Server.java:351)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:454)
        at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:890)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:944)
        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:77)
        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)
        at java.lang.Thread.run(Thread.java:724)

The Entity: 

@Entity(name = "recipe")
public class Recipe {

@Id
@GeneratedValue
private Long id;

private String name;

private Integer duration;

@Enumerated(EnumType.STRING)
private Difficulty difficulty;

@OneToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "recipe")
List<Ingredient> ingredients;

The code where the exception is thrown:

@Service
@Transactional
public class RecipeServiceImpl implements RecipeService {
private final RecipeRepository recipeRepository;

@Autowired
public RecipeServiceImpl(RecipeRepository recipeRepository) {
    this.recipeRepository = recipeRepository;
}

@Override
public Recipe get(Long id) {
    Recipe recipe = recipeRepository.findOne(id);
    if(recipe == null) {
        throw new EntityNotFoundException("Recipe with id: " + id + " was not found.");
    }
    recipe.getIngredients();
    return recipe;
}

And my Spring config:

@Configuration
@ComponentScan(basePackages = "de.recipemanager")
@EnableWebMvc
public class ApplicationContext {
}

@Configuration
@PropertySource("classpath:application.properties")
@EnableJpaRepositories(basePackages = "de.recipemanager")
@EnableTransactionManagement
public class JPAContext {

    private static final String PROPERTY_NAME_DATABASE_DRIVER = "db.driver";
    private static final String PROPERTY_NAME_DATABASE_URL = "db.url";
    private static final String PROPERTY_NAME_DATABASE_USERNAME = "db.username";
    private static final String PROPERTY_NAME_DATABASE_PASSWORD = "db.password";

    private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN = "entitymanager.packages.to.scan";
    private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
    private static final String PROPERTY_NAME_HIBERNATE_FORMAT_SQL = "hibernate.format_sql";
    private static final String PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY = "hibernate.ejb.naming_strategy";
    private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";
    private static final String PROPERTY_NAME_HIBERNATE_AUTO = "hibernate.hbm2ddl.auto";


    @Resource
    private Environment environment;

    @Bean
    public DataSource dataSource() throws PropertyVetoException {
        ComboPooledDataSource dataSource = new ComboPooledDataSource();
        dataSource.setDriverClass(environment.getRequiredProperty(PROPERTY_NAME_DATABASE_DRIVER));
        dataSource.setJdbcUrl(environment.getRequiredProperty(PROPERTY_NAME_DATABASE_URL));
        dataSource.setUser(environment.getRequiredProperty(PROPERTY_NAME_DATABASE_USERNAME));
        dataSource.setPassword(environment.getRequiredProperty(PROPERTY_NAME_DATABASE_PASSWORD));

        return dataSource;
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() throws ClassNotFoundException, PropertyVetoException {
        LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();

        entityManagerFactoryBean.setDataSource(dataSource());
        entityManagerFactoryBean.setPackagesToScan(
                environment.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));
        entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistence.class);

        Properties jpaProperties = new Properties();
        jpaProperties.put(PROPERTY_NAME_HIBERNATE_DIALECT, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_DIALECT));
        jpaProperties.put(PROPERTY_NAME_HIBERNATE_AUTO, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_AUTO));
        jpaProperties.put(PROPERTY_NAME_HIBERNATE_FORMAT_SQL, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_FORMAT_SQL));
        jpaProperties.put(PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_NAMING_STRATEGY));
        jpaProperties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, environment.getRequiredProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));

        entityManagerFactoryBean.setJpaProperties(jpaProperties);

        return entityManagerFactoryBean;
    }

    @Bean
    public JpaTransactionManager transactionManager() throws ClassNotFoundException, PropertyVetoException {
        JpaTransactionManager transactionManager = new JpaTransactionManager();

        transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());

        return transactionManager;
    }


}

I hope someone can help my figure out the solution for my problem, and sorry for my bad english.

Solution

I could get it work by calling the size() attribute of the Ingredientslist.

@Service
@Transactional
public class RecipeServiceImpl implements RecipeService {

    private final RecipeRepository recipeRepository;

    @Autowired
    public RecipeServiceImpl(RecipeRepository recipeRepository) {
        this.recipeRepository = recipeRepository;
    }

    @Override
    public Recipe get(Long id) {
        Recipe recipe = recipeRepository.findOne(id);
        if(recipe == null) {
            throw new EntityNotFoundException("Recipe with id: " + id + " was not found.");
        }
        recipe.getIngredients().size(); //Needed to fetch the Ingredients in the open Transaction.
        return recipe;
    }

1条回答
做自己的国王
2楼-- · 2019-06-27 20:05

Once you leave this @Transactional method

@Override
public Recipe get(Long id) {
    Recipe recipe = recipeRepository.findOne(id);
    if(recipe == null) {
        throw new EntityNotFoundException("Recipe with id: " + id + " was not found.");
    }
    recipe.getIngredients();
    return recipe;
}

The TransactionManager commits/rollsback the transaction and closes the session. As such, for any entities that were lazy loaded, the Session object that was attached is either null or is closed. Those entities cannot therefore be loaded and hibernate throws an Exception. You will need to either put a broader Session scope, possibly with an OpenSessionInViewFilter, eagerly load your entities, or force some of their initializations (the ones you need) inside the @Transactional method.

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