相关疑难解决方法(0)

我有这个问题:

org.hibernate.LazyInitializationException:懒得初始化角色集合:mvc3.model.Topic.comments,没有会话或会话被关闭

这是模型:

@Entity
@Table(name = "T_TOPIC")
public class Topic {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;

    @ManyToOne
    @JoinColumn(name="USER_ID")
    private User author;

    @Enumerated(EnumType.STRING)    
    private Tag topicTag;

    private String name;
    private String text;

    @OneToMany(mappedBy = "topic", cascade = CascadeType.ALL)
    private Collection<Comment> comments = new LinkedHashSet<Comment>();

    ...

    public Collection<Comment> getComments() {
           return comments;
    }

}

调用模型的控制器如下所示:

@Controller
@RequestMapping(value = "/topic")
public class TopicController {

    @Autowired
    private TopicService service;

    private static final Logger logger = LoggerFactory.getLogger(TopicController.class);


    @RequestMapping(value = "/details/{topicId}", method = RequestMethod.GET)
    public ModelAndView …

Spring文档在描述事务传播属性方面做得非常出色.

但是,我想知道是否有任何众所周知的现实世界的例子可以用外行的方式更全面地描述这些属性？