我有一个模型,它有一个相当庞大的子实体图,并且Hibernate最终会进行约9个语句才能懒加载所需的所有数据,但是到了大约4层深度,我遇到了“无法初始化代理 - 没有会话”错误,我不确定原因。
控制器
@Transactional(readOnly = true)
@RequestMapping(value = "/v2/plans", method = RequestMethod.GET)
public @ResponseBody List<PlanPresenter> show(HttpServletRequest request) throws Exception {
List<PlanPresenter> planPresenters = new ArrayList<>();
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Plan> planQuery = criteriaBuilder.createQuery(Plan.class);
Root<Plan> root = planQuery.from(Plan.class);
if (request.getParameter("region") != null || request.getParameter("group") != null) {
List<Predicate> criteria = new ArrayList<Predicate>();
if (request.getParameter("region") != null) {
criteria.add(criteriaBuilder.equal(root.get(Plan_.region), request.getParameter("region")));
}
if (request.getParameter("group") != null) {
criteria.add(criteriaBuilder.equal(root.get(Plan_.groupCode), request.getParameter("group")));
criteria.add(root.get(Plan_.planSetId).in(groupPlanSetIds));
} else {
criteria.add(root.get(Plan_.planSetId).in(currentPlanSetIds));
}
Query query = entityManager.createQuery(planQuery.where(criteriaBuilder.and(criteria.toArray(new Predicate[]{}))));
for (Plan plan : (List<Plan>)query.getResultList()) {
planPresenters.add(new PlanPresenter(plan));
}
}
return planPresenters;
}
演示者
public class PlanPresenter {
public String id;
public String plan_set_id;
public String region;
public String name;
public String description;
public HashMap<String, Object> details = new HashMap<String, Object>();
public PlanPresenter(Plan plan) throws Exception {
this.id = String.valueOf(plan.id);
this.plan_set_id = String.valueOf(plan.planSetId);
this.region = plan.region.trim();
this.name = plan.getName();
this.description = plan.getDescription();
this.details.put("spanish_plan", plan.isSpanishPlan());
this.details.put("mutually_exclusive", plan.isMutuallyExclusive());
this.details.put("group_plan", plan.isGroupPlan());
this.details.put("group_code", plan.groupCode.trim());
this.details.put("family_plan", plan.isFamilyPlan());
this.details.put("price", plan.getPrice());
this.details.put("enrollment_fee", plan.getEnrollmentFee());
this.details.put("riders", plan.getRiders());
}
}
计划@Entity
public class Plan implements Serializable {
private static final long serialVersionUID = 7639611964474770505L;
private static List<String> familyPlanShortNames = Arrays.asList("ABCD");
@Transient
private String description = "";
(Column definitions)
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "XXXX", insertable = false, updatable = false, nullable = true)
@NotFound(action = NotFoundAction.IGNORE)
public PlanDetail planDetail;
@OneToMany(fetch = FetchType.LAZY)
@JoinColumn(name = "XXXX", insertable = false, updatable = false, nullable = true)
@OrderBy("XXXX")
@NotFound(action = NotFoundAction.IGNORE)
public List<Rider> riders;
public String getName() {
return this.planDetail != null ? this.planDetail.longName.trim() : null;
}
public Boolean isSpanishPlan() {
return this.language.trim().equals("ES");
}
public Boolean isMutuallyExclusive() {
return this.mutuallyExclusive.trim().equals("Y");
}
public Boolean isGroupPlan() {
return this.groupCode != null && !this.groupCode.trim().equals("");
}
public Boolean isFamilyPlan() {
return familyPlanShortNames.contains(this.planDetail.shortName.trim());
}
public BigDecimal getPrice() {
return this.planDetail != null ? this.planDetail.price.setScale(2) : null;
}
public BigDecimal getEnrollmentFee() {
return this.planDetail != null ? this.planDetail.enrollmentFee.setScale(2) : null;
}
public String getDescription() {
if (this.planDetail != null && this.planDetail.brochureSections != null) {
this.planDetail.brochureSections.forEach((brochureSection) -> {
if (brochureSection.type.trim().equals("P1") && brochureSection.order == 1) {
this.description = this.description + " " + brochureSection.text.trim();
}
});
}
return this.description.trim();
}
public List<HashMap<String, Object>> getRiders() {
List<HashMap<String, Object>> riders = new ArrayList<HashMap<String, Object>>();
if (this.riders != null && this.riders.size() > 0) {
this.riders.forEach((rider) -> {
HashMap<String, Object> planRider = new HashMap<String, Object>();
planRider.put("name", rider.getName());
planRider.put("price", rider.getPrice());
planRider.put("description", rider.getDescription());
riders.add(planRider);
});
}
return riders;
}
}
计划详情
@Entity
public class PlanDetail implements Serializable {
private static final long serialVersionUID = 2256881691562712018L;
(Column definitions)
@OneToMany(fetch = FetchType.LAZY)
@JoinColumn(name = "XXXX", referencedColumnName = "XXXX", insertable = false, updatable = false, nullable = true)
@OrderBy("XXXX")
@NotFound(action = NotFoundAction.IGNORE)
public List<BrochureSection> brochureSections;
}
宣传册章节
@Entity
public class BrochureSection implements Serializable {
private static final long serialVersionUID = 1856191232387921427L;
(Column definitions)
}
异常
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.models.PlanDetail.brochureSections, could not initialize proxy - no Session
at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:576) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:215) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:555) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:143) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
at org.hibernate.collection.internal.PersistentBag.iterator(PersistentBag.java:294) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
at java.lang.Iterable.forEach(Iterable.java:74) ~[?:1.8.0_66]
at com.models.Plan.getDescription(Plan.java:100) ~[classes/:?]
at com.presenters.v2.PlanPresenter.<init>(PlanPresenter.java:20) ~[classes/:?]
at com.controllers.v2.PlansController.show(PlansController.java:64) ~[classes/:?]
非常感谢任何帮助。
@EnableTransactionManagement
(如果使用XML,则添加<tx:annotation-driven />
)。如果你已经这样做了,但是由ContextLoaderListener
加载,它将不起作用,因为AOP只应用于同一应用程序上下文中。 - M. DeinummyEntity.getListOfThings().size();
强制 JPA 初始化集合。 - Anton N