无法获取LAZY - JPA

时间：2013-10-10 19:34:05

标签： java spring hibernate jpa spring-data-jpa

我想在JPA中的OneToMany关系中进行LAZY加载。

问题是，当我想访问LAZY加载的属性时，我得到一个例外。我知道在尝试访问该属性时我必须处于事务中。但似乎交易不公开。这是例外：

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)

实体：

@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;

抛出异常的代码：

@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;
}

我的Spring配置：

@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;
    }


}

我希望有人可以帮助我解决问题的解决方案，并抱歉我的英语不好。

解决方案

我可以通过调用Ingredientslist的size（）属性来实现它。

@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 个答案:

答案 0 :(得分：4)

离开此@Transactional方法

@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;
}

TransactionManager提交/回滚事务并关闭会话。因此，对于延迟加载的任何实体，附加的Session对象为null或已关闭。因此无法加载这些实体，并且hibernate会抛出异常。您需要放置更广泛的Session范围，可能使用OpenSessionInViewFilter，急切地加载您的实体，或者在@Transactional方法中强制执行一些初始化（您需要的）。

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