未能懒惰地初始化角色集合：br.com.coderi.adi.model.Usuario.papeis，无法初始化代理 - 没有会话

时间：2016-07-08 01:46:18

标签： java spring-mvc spring-data-jpa

我正在使用 Spring-MVC 和 Spring-在实体@OneToMany和@ManyToOne之间的关系中使用 Java 1.8 Data-JPA ，但我收到以下错误：

GRAVE: Servlet.service() for servlet [appServlet] in context with path [/adi] threw exception [Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: br.com.coderi.adi.model.Usuario.papeis, could not initialize proxy - no Session] with root cause
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: br.com.coderi.adi.model.Usuario.papeis, could not initialize proxy - no Session

我可以添加用户（Usuario）及其角色（Papeis），但执行查询时始终会出现上述错误。

实体 Usuario ： 

@Entity
public class Usuario {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @NotEmpty
    private String nome;

    @NotEmpty
    private String email;

    @NotEmpty
    @Size(min = 2, max = 25)
    @Column(unique = true)
    private String login;

    @NotEmpty
    @Size(min = 6)
    private String senha;

    @Transient
    private String confirmSenha;

    private Boolean status;

    @OneToMany(mappedBy = "usuario")
    private List<Papel> papeis;

    <!-- Getters/Setters... -->
}

实体 Papel ： 

@Entity
public class Papel {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @NotEmpty
    private String papel;

    @ManyToOne
    private Usuario usuario;

    <!-- Getters/Setters... -->
}

用户（Usuario）可以拥有多个角色（Papel），各种角色必须属于用户。这是正确的方法吗？

服务： 

@Service
public class PapelService {

    @Autowired
    private PapelReposiroty papelRepository;

    public Papel getPapel(Integer id) {
        return papelRepository.findOne(id);
    }

    public Papel adicionar(Papel papel) {
        return papelRepository.save(papel);
    }

    public List<Papel> listarPapeisPorUsuario(Usuario usuario) {
        return papelRepository.findPapelByUsuario(usuario);
    }
}

存储库： 

@Repository
public interface PapelReposiroty extends CrudRepository<Papel, Integer> {
    public List<Papel> findPapelByUsuario(Usuario usuario);
}

在执行papelService.getPapel(1)后添加用户/角色后，在我的控制器中，我得到了这个引用错误。谢谢你的帮助！

  

Ps：仅在使用关系方法时才会发生错误。

数据库： Database

所有堆栈跟踪：

GRAVE: Servlet.service() for servlet [appServlet] in context with path [/adi] threw exception [Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: br.com.coderi.adi.model.Usuario.papeis, could not initialize proxy - no Session] with root cause
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: br.com.coderi.adi.model.Usuario.papeis, could not initialize proxy - no Session
at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:579)
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:203)
at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:558)
at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:131)
at org.hibernate.collection.internal.PersistentBag.toString(PersistentBag.java:509)
at java.lang.String.valueOf(String.java:2982)
at java.lang.StringBuilder.append(StringBuilder.java:131)
at br.com.coderi.adi.model.Usuario.toString(Usuario.java:113)
at java.lang.String.valueOf(String.java:2982)
at java.lang.StringBuilder.append(StringBuilder.java:131)
at br.com.coderi.adi.model.Papel.toString(Papel.java:66)
at java.lang.String.valueOf(String.java:2982)
at java.io.PrintStream.println(PrintStream.java:821)
at org.apache.tomcat.util.log.SystemLogHandler.println(SystemLogHandler.java:267)
at br.com.coderi.adi.controller.PapelController.adicionarForm(PapelController.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:114)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:115)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:112)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:169)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:158)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:206)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:121)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:66)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:106)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1526)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1482)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

2 个答案:

答案 0 :(得分：1)

  
    

如何在Hibernate中启用延迟加载

  
     

在进一步研究之前，重新调整默认行为非常重要   在使用hibernate映射与注释的情况下延迟加载。

     

默认行为是急切加载'属性值'并加载   '懒洋洋地收藏'。与你可能记得的相反，如果你有   之前使用普通的Hibernate 2（映射文件），其中所有引用   （包括集合）默认情况下会急切加载。另请注意   @OneToMany和@ManyToMany协会默认为LAZY加载;   和@OneToOne和@ManyToOne默认为EAGER加载。这是   重要的是要记住以后避免任何陷阱。

     

要明确启用延迟加载，必须使用＆＃34; fetch =   FetchType.LAZY＆＃34;在你想要延迟加载的关联上   正在使用hibernate注释。

     

示例用法如下所示：

     

@OneToMany（mappedBy =＆＃34; category＆＃34;，fetch = FetchType.LAZY）private   设置产品;另一个属性平行于   ＆＃34; FetchType.LAZY＆＃34;是＆＃34; FetchType.EAGER＆＃34;这与LAZY正好相反   即，当所有者实体是时，它也将加载关联实体   第一次参加。

     

懒惰加载如何在Hibernate中工作

     

Hibernate可以在您的应用程序上应用延迟加载行为的最简单方法   实体和关联是通过提供代理实现的   他们。 Hibernate通过替换代理拦截对实体的调用   因为它来自实体的类。请求的地方   信息丢失，之前将从数据库加载   控制权转交给母公司的实施。

     

请注意，当关联表示为集合时   class，然后是一个包装器（基本上是集合的代理，而不是   而不是它所包含的实体）被创建和替换   原来的收藏品。当您访问此集合代理时   你在返回的代理集合中得到的不是代理实体;   相反，它们是实体。你不需要施加太大的压力   理解这个概念，因为在运行时它几乎不重要。

您使用@O​​netoMany关系。

我知道要解决。

您使用获取。

您的实体

@Entity
public class Usuario {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @NotEmpty
    private String nome;

    @NotEmpty
    private String email;

    @NotEmpty
    @Size(min = 2, max = 25)
    @Column(unique = true)
    private String login;

    @NotEmpty
    @Size(min = 6)
    private String senha;

    @Transient
    private String confirmSenha;

    private Boolean status;

    @OneToMany(mappedBy = "usuario")
    private List<Papel> papeis;

    <!-- Getters/Setters... -->
}

你搜索＆＃34; jpa fetch lazy＆＃34;。 但。获取，许多搜索关系。 ：）

答案 1 :(得分：1)

IT无法运行的原因是因为您的会话已关闭。这可以在事务END之后自动发生。然后实体进入“分离”状态。当发生这种情况时，对未初始化的惰性代理的所有访问都将导致此异常。当然，最简单的解决方法是将IT AS EAGER标记为。如果您想让IT保持懒惰，那么为了修复IT，您需要在IT分离之前在事务中初始化此集合。如果你不在transactin中包装你的服务，另一种方法是使用带有fetch子句的HQL查询来确保初始化集合。如果您按照这些步骤操作，则可以保留LAZY FetchType

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