Java 无法延迟初始化集合.. 没有会话或会话被关闭
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时间：2020-08-11 01:01:50 来源:igfitidea点击:
Failed to lazily initialize a collection.. no session or session was closed
提问by Joe
I don't know what else to try, I've updated to Hymanson 2, changed to Lazy, used @JsonIgnore... but nothing worked out. Any idea what can it be?
我不知道还能尝试什么，我已经更新到 Hymanson 2，改为 Lazy，使用 @JsonIgnore ......但没有任何效果。知道它是什么吗？
Environment
环境
- Spring MVC 3.2.5
- Hymanson 2.2
- Hibernate 3.5.4
- 春季MVC 3.2.5
- Hyman逊 2.2
- 休眠 3.5.4
ERROREstado HTTP 500 - Could not write JSON: failed to lazily initialize a collection of role: com.javalabs.web.dao.Task.actions, no session or session was closed (through reference chain: java.util.HashMap["actions"]->java.util.ArrayList[0]->com.javalabs.web.dao.TaskAction["task"]->com.javalabs.web.dao.Task["actions"]); nested exception is com.fasterxml.Hymanson.databind.JsonMappingException: failed to lazily initialize a collection of role: com.javalabs.web.dao.Task.actions, no session or session was closed (through reference chain: java.util.HashMap["actions"]->java.util.ArrayList[0]->com.javalabs.web.dao.TaskAction["task"]->com.javalabs.web.dao.Task["actions"])
错误Estado HTTP 500 - 无法写入 JSON：无法延迟初始化角色集合：com.javalabs.web.dao.Task.actions，没有关闭会话或会话（通过引用链：java.util.HashMap["actions "]->java.util.ArrayList[0]->com.javalabs.web.dao.TaskAction["task"]->com.javalabs.web.dao.Task["actions"]); 嵌套异常是 com.fasterxml.Hymanson.databind.JsonMappingException：未能延迟初始化角色集合：com.javalabs.web.dao.Task.actions，没有会话或会话被关闭（通过引用链：java.util.HashMap ["actions"]->java.util.ArrayList[0]->com.javalabs.web.dao.TaskAction["task"]->com.javalabs.web.dao.Task["actions"])
Error trace
错误跟踪
org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: failed to lazily initialize a collection of role: com.javalabs.web.dao.Task.actions, no session or session was closed (through reference chain: java.util.HashMap["actions"]->java.util.ArrayList[0]->com.javalabs.web.dao.TaskAction["task"]->com.javalabs.web.dao.Task["actions"]); nested exception is com.fasterxml.Hymanson.databind.JsonMappingException: failed to lazily initialize a collection of role: com.javalabs.web.dao.Task.actions, no session or session was closed (through reference chain: java.util.HashMap["actions"]->java.util.ArrayList[0]->com.javalabs.web.dao.TaskAction["task"]->com.javalabs.web.dao.Task["actions"])
org.springframework.http.converter.json.MappingHymanson2HttpMessageConverter.writeInternal(MappingHymanson2HttpMessageConverter.java:207)
org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:179)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:148)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:90)
org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:189)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:69)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)
causa raíz
com.fasterxml.Hymanson.databind.JsonMappingException: failed to lazily initialize a collection of role: com.javalabs.web.dao.Task.actions, no session or session was closed (through reference chain: java.util.HashMap["actions"]->java.util.ArrayList[0]->com.javalabs.web.dao.TaskAction["task"]->com.javalabs.web.dao.Task["actions"])
com.fasterxml.Hymanson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:232)
com.fasterxml.Hymanson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:197)
com.fasterxml.Hymanson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:184)
com.fasterxml.Hymanson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:605)
com.fasterxml.Hymanson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142)
com.fasterxml.Hymanson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:569)
com.fasterxml.Hymanson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:597)
com.fasterxml.Hymanson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142)
com.fasterxml.Hymanson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:100)
com.fasterxml.Hymanson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:21)
com.fasterxml.Hymanson.databind.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:186)
com.fasterxml.Hymanson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:394)
com.fasterxml.Hymanson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:315)
com.fasterxml.Hymanson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:27)
com.fasterxml.Hymanson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118)
com.fasterxml.Hymanson.databind.ObjectMapper.writeValue(ObjectMapper.java:1819)
org.springframework.http.converter.json.MappingHymanson2HttpMessageConverter.writeInternal(MappingHymanson2HttpMessageConverter.java:204)
org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:179)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:148)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:90)
org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:189)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:69)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)
causa raíz
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.javalabs.web.dao.Task.actions, no session or session was closed
org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383)
org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375)
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:368)
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:111)
org.hibernate.collection.PersistentBag.iterator(PersistentBag.java:272)
com.fasterxml.Hymanson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:90)
com.fasterxml.Hymanson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:23)
com.fasterxml.Hymanson.databind.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:186)
com.fasterxml.Hymanson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:569)
com.fasterxml.Hymanson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:597)
com.fasterxml.Hymanson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142)
com.fasterxml.Hymanson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:569)
com.fasterxml.Hymanson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:597)
com.fasterxml.Hymanson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142)
com.fasterxml.Hymanson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:100)
com.fasterxml.Hymanson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:21)
com.fasterxml.Hymanson.databind.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:186)
com.fasterxml.Hymanson.databind.ser.std.MapSerializer.serializeFields(MapSerializer.java:394)
com.fasterxml.Hymanson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:315)
com.fasterxml.Hymanson.databind.ser.std.MapSerializer.serialize(MapSerializer.java:27)
com.fasterxml.Hymanson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118)
com.fasterxml.Hymanson.databind.ObjectMapper.writeValue(ObjectMapper.java:1819)
org.springframework.http.converter.json.MappingHymanson2HttpMessageConverter.writeInternal(MappingHymanson2HttpMessageConverter.java:204)
org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:179)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:148)
org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:90)
org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:189)
org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:69)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)
MODEL
模型
TaskController.java
任务控制器
@Controller
public class TaskController {
...
@RequestMapping(value = "/getactions/{id}", method = RequestMethod.GET, produces = "application/json")
public @ResponseBody Map<String, Object> getActions(Principal principal,
@PathVariable Long id) {
logger.info("Task controller get actions...");
List<TaskAction> actions = null;
if (principal == null) {
actions = new ArrayList<TaskAction>();
} else {
actions = taskActionService.getAllTaskActions(id);
}
Map<String, Object> data = new HashMap<String, Object>();
data.put("actions", actions);
data.put("number", actions.size());
return data;
}
}
Task.java
任务.java
@Entity
@Table(name = "t_task")
public class Task {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "idTask")
private long idTask;
@Size(min = 5, max = 100)
@Column(name = "taskname")
private String taskname;
...
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "task", orphanRemoval = true)
private List<TaskAction> actions = new ArrayList<TaskAction>();
@Column(name = "timestamp")
private Timestamp timestamp;
...
}
User.java@Entity @Table(name = "t_user") public class User {
User.java@Entity @Table(name = "t_user") 公共类用户{
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name = "idUser")
private long idUser;
...
@ManyToMany(cascade = { CascadeType.ALL })
@JsonIgnore
@JoinTable(name = "r_userrole", joinColumns = { @JoinColumn(name = "idUser") }, inverseJoinColumns = { @JoinColumn(name = "idRole") })
private Set<Role> roles = new HashSet<Role>();
... }
... }
TaskAction.java
任务操作.java
@Entity
@Table(name = "t_taskaction")
public class TaskAction {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "idTaskAction")
private long idTaskAction;
@ManyToOne
@JoinColumn(name = "idTask", nullable = false)
private Task task;
...
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "idUser", nullable = false)
private User user;
@Column(name = "timestamp")
private Date timestamp;
...
}
TaskActionDao.java
TaskActionDao.java
@Repository
@Transactional
@Component("taskActionDao")
public class TaskActionDao {
@Autowired
private SessionFactory sessionFactory;
public Session session() {
return sessionFactory.getCurrentSession();
}
...
@SuppressWarnings("unchecked")
public List<TaskAction> getAllTaskActions() {
Query q = session().createQuery("from TaskAction");
List<TaskAction> la = q.list();
//createQuery("from TaskAction").list();
System.out.println(">>>>>>>>>>getAllActions>>>>>>>>>>> " + la.size());
return la;
}
@SuppressWarnings("unchecked")
public List<TaskAction> getAllTaskActions(long idTask) {
Criteria crit = session().createCriteria(TaskAction.class);
crit.add(Restrictions.eq("task.idTask", idTask));
System.out.println(">>>>>>>>getAllActions(id)>>>>>>>>>>>>> " + crit.list().size());
return crit.list();
}
}
采纳答案by maszter
Fist of all, we don't need User.java at all here. It has nothing to it. The issue is related to Task.actions. You load collection of TaskAction, TaskAction has Task and this Task has collection of TaskAction which cannot be initialized. You can add @JsonIgnoreto:
首先，我们在这里根本不需要 User.java。它没有任何关系。该问题与 Task.actions 相关。您加载 TaskAction 的集合，TaskAction 具有 Task，而此 Task 具有无法初始化的 TaskAction 集合。您可以添加@JsonIgnore到：
private List<TaskAction> actions = new ArrayList<TaskAction>(); //Task class
or to:
或者：
private Task task; //TaskAction class
You can also try with changing FetchType.LAZYto FetchType.EAGERfor collection of actions in Task.java, however I'm not sure it's going to work (circular references)
您也可以尝试与改变FetchType.LAZY，以FetchType.EAGER用于在Task.java行动收集，但我不知道它会工作（循环引用）
回答by Joe
I've recently encountered a similar problem: Hymanson version 1.9 and lower with birectional relationships (avoiding cycles)
我最近遇到了类似的问题：Hymanson 1.9 及更低版本，具有双向关系（避免循环）
And the solution seems to upgrade to Hymanson 2.0, and add to classes the following annotation:
并且解决方案似乎升级到 Hymanson 2.0，并在类中添加以下注释：
@JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class,
property = "idTaskAction")
public class TaskAction
回答by Yoku
I had an issue showing the exception same as above, complaining about the 'no session' but I found that the problem was due to the Entity being referenced in the DTO rather than its ID. So just in case above problem occurs I will suggest to check if one hasn't caused any serialization issue.
我有一个问题，显示与上面相同的异常，抱怨“无会话”，但我发现问题是由于在 DTO 中引用了实体而不是它的 ID。所以以防万一发生上述问题，我会建议检查是否没有引起任何序列化问题。
回答by Tribuwan Singh
Since you are accessing your Object outside the Hibernate Session object, so you should add the annotation @JsonIgnore before each @OneToMany annotation in your model
由于您正在 Hibernate Session 对象之外访问您的对象，因此您应该在模型中的每个 @OneToMany 注释之前添加注释 @JsonIgnore
回答by Shahid Hussain Abbasi
Please add annotation @JsonIgnore before each @OneToMany annotation in you entity class My solution
请在实体类中的每个@OneToMany 注释之前添加注释@JsonIgnore 我的解决方案
@JsonIgnore
@OneToMany(cascade = CascadeType.ALL, mappedBy = "domainDataId")
Thank Shahid Hussain Abbasi
感谢沙希德·侯赛因·阿巴西
