Java 计划任务中的Spring事务-分离实体错误

（我知道类似的问题到处都是，但我找不到合适的解决方案。）

我有一个Spring计划的任务，它通过Spring存储库/Hibernate从数据库读写，包括两个实体之间的多对多关系，需要对延迟初始化的集合进行适当的会话管理

但是，尽管有注释，Spring似乎无法正确管理事务

我做错了什么

（我应该提到在相同的方法上抛出一个

@Transactional

，该方法与

@Scheduled

有效，但会导致整个计划任务成为一个事务，而我希望

persistbanerCourse

是事务性的。）

首先是堆栈跟踪，然后是相关代码：

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: edu.ucdavis.dss.dw.entities.Instructor.courses, could not initialize proxy - no Session
at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:572) ~[AbstractPersistentCollection.class:4.3.1.Final]
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:212) ~[AbstractPersistentCollection.class:4.3.1.Final]
at org.hibernate.collection.internal.AbstractPersistentCollection.readElementExistence(AbstractPersistentCollection.java:319) ~[AbstractPersistentCollection.class:4.3.1.Final]
at org.hibernate.collection.internal.PersistentBag.contains(PersistentBag.java:288) ~[PersistentBag.class:4.3.1.Final]
at edu.ucdavis.dss.dw.entities.Instructor.addCourse(Instructor.java:130) ~[Instructor.class:?]
at edu.ucdavis.dss.dw.entities.Course.addInstructor(Course.java:111) ~[Course.class:?]
at edu.ucdavis.dss.dw.entities.Course.addInstructor(Course.java:100) ~[Course.class:?]
at edu.ucdavis.dss.dw.tasks.BannerTasks.persistBannerCourse(BannerTasks.java:184) ~[BannerTasks.class:?]
at edu.ucdavis.dss.dw.tasks.BannerTasks.bannerImport(BannerTasks.java:80) ~[BannerTasks.class:?]
at edu.ucdavis.dss.dw.tasks.BannerTasks$$FastClassBySpringCGLIB$$d1348e2.invoke(<generated>) ~[ReflectUtils.class:?]
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) ~[MethodProxy.class:4.0.4.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:640) ~[CglibAopProxy$DynamicAdvisedInterceptor.class:4.0.4.RELEASE]
at edu.ucdavis.dss.dw.tasks.BannerTasks$$EnhancerBySpringCGLIB$$46afeb46.bannerImport(<generated>) ~[ReflectUtils.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0]
at java.lang.reflect.Method.invoke(Method.java:483) ~[?:1.8.0]
at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:65) ~[ScheduledMethodRunnable.class:4.0.4.RELEASE]
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54) [DelegatingErrorHandlingRunnable.class:4.0.4.RELEASE]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [?:1.8.0]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [?:1.8.0]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [?:1.8.0]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0]
at java.lang.Thread.run(Thread.java:744) [?:1.8.0]

CourseManager.java：

package edu.ucdavis.dss.dw.site;

import edu.ucdavis.dss.dw.entities.Course;
import edu.ucdavis.dss.dw.entities.Department;
import edu.ucdavis.dss.dw.entities.Instructor;
import edu.ucdavis.dss.dw.entities.Term;

import java.util.List;

import javax.validation.Valid;
import javax.validation.constraints.NotNull;

import org.springframework.validation.annotation.Validated;

@Validated
public interface CourseManager
{
List<Instructor> getInstructors();

List<Course> getCourses();

List<Department> getDepartments();

void saveInstructor(@NotNull @Valid Instructor instructor);

void saveCourse(Course course);

void saveDepartment(@NotNull @Valid Department department);

void saveTerm(Term term);

Term getTermById(Long id);

Department getDepartmentByCode(String departmentCode);

Term getTermByCode(String termCode);

Instructor getInstructorByEmployeeId(String employeeId);

Course getCourseByCrnAndTerm(String crn, long termId);

long countCourses();
}

package edu.ucdavis.dss.dw.site;

import edu.ucdavis.dss.dw.entities.Course;
import edu.ucdavis.dss.dw.entities.Department;
import edu.ucdavis.dss.dw.entities.Instructor;
import edu.ucdavis.dss.dw.entities.Term;
import edu.ucdavis.dss.dw.repositories.CourseRepository;
import edu.ucdavis.dss.dw.repositories.DepartmentRepository;
import edu.ucdavis.dss.dw.repositories.InstructorRepository;
import edu.ucdavis.dss.dw.repositories.TermRepository;

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.inject.Inject;

import java.util.ArrayList;
import java.util.List;

@Service
public class DefaultCourseManager implements CourseManager
{
@Inject InstructorRepository instructorRepository;
@Inject CourseRepository courseRepository;
@Inject DepartmentRepository departmentRepository;
@Inject TermRepository termRepository;

@Override
@Transactional
public List<Instructor> getInstructors()
{
    return this.toList(this.instructorRepository.findAll());
}

@Override
@Transactional
public List<Course> getCourses()
{
    return this.toList(this.courseRepository.findAll());
}

@Override
@Transactional
public List<Department> getDepartments()
{
    return this.toList(this.departmentRepository.findAll());
}

private <E> List<E> toList(Iterable<E> i)
{
    List<E> list = new ArrayList<>();
    i.forEach(list::add);
    return list;
}

@Override
@Transactional
public void saveInstructor(Instructor instructor)
{
    this.instructorRepository.save(instructor);
}

@Override
@Transactional
public void saveCourse(Course course)
{
    this.courseRepository.save(course);
}

@Override
@Transactional
public void saveDepartment(Department department)
{
    this.departmentRepository.save(department);
}

@Override
@Transactional
public void saveTerm(Term term)
{
    this.termRepository.save(term);
}

@Override
@Transactional
public Term getTermById(Long id)
{
    return this.termRepository.findOne(id);
}

@Override
@Transactional
public Department getDepartmentByCode(String departmentCode)
{
    return this.departmentRepository.getOneByCode(departmentCode);
}

@Override
@Transactional
public Term getTermByCode(String termCode)
{
    return this.termRepository.getOneByCode(termCode);
}

@Override
@Transactional
public Instructor getInstructorByEmployeeId(String employeeId)
{
    return this.instructorRepository.getOneByEmployeeId(employeeId);
}

@Override
@Transactional
public Course getCourseByCrnAndTerm(String crn, long termId)
{
    return this.courseRepository.getOneByCrnAndTermId(crn, termId);
}

@Override
@Transactional
public long countCourses()
{
    return this.courseRepository.count();
}
}

包edu.ucdavis.dss.dw.site；
导入edu.ucdavis.dss.dw.entities.Course；
导入edu.ucdavis.dss.dw.entities.Department；
导入edu.ucdavis.dss.dw.entities.讲师；
导入edu.ucdavis.dss.dw.entities.Term；
导入java.util.List；
导入javax.validation.Valid；
导入javax.validation.constraints.NotNull；
导入org.springframework.validation.annotation.Validated；
@验证
公共接口课程管理员
{
列出getInstructors（）；
列出getCourses（）；
列出部门（）；
无效保存讲师（@NotNull@有效讲师）；
无效保存课程（课程）；
作废保存部门（@NotNull@有效部门）；
无效保存期限（期限）；
术语getTermById（长id）；
部门getDepartmentByCode（字符串departmentCode）；
术语getTermByCode（字符串termCode）；
讲师getInstructorByEmployeeId（字符串employeeId）；
课程getCourseByCrnAndTerm（字符串crn，长期ID）；
长课程（）；
}

DefaultCourseManager.java：

package edu.ucdavis.dss.dw.site;

import edu.ucdavis.dss.dw.entities.Course;
import edu.ucdavis.dss.dw.entities.Department;
import edu.ucdavis.dss.dw.entities.Instructor;
import edu.ucdavis.dss.dw.entities.Term;

import java.util.List;

import javax.validation.Valid;
import javax.validation.constraints.NotNull;

import org.springframework.validation.annotation.Validated;

@Validated
public interface CourseManager
{
List<Instructor> getInstructors();

List<Course> getCourses();

List<Department> getDepartments();

void saveInstructor(@NotNull @Valid Instructor instructor);

void saveCourse(Course course);

void saveDepartment(@NotNull @Valid Department department);

void saveTerm(Term term);

Term getTermById(Long id);

Department getDepartmentByCode(String departmentCode);

Term getTermByCode(String termCode);

Instructor getInstructorByEmployeeId(String employeeId);

Course getCourseByCrnAndTerm(String crn, long termId);

long countCourses();
}

package edu.ucdavis.dss.dw.site;

import edu.ucdavis.dss.dw.entities.Course;
import edu.ucdavis.dss.dw.entities.Department;
import edu.ucdavis.dss.dw.entities.Instructor;
import edu.ucdavis.dss.dw.entities.Term;
import edu.ucdavis.dss.dw.repositories.CourseRepository;
import edu.ucdavis.dss.dw.repositories.DepartmentRepository;
import edu.ucdavis.dss.dw.repositories.InstructorRepository;
import edu.ucdavis.dss.dw.repositories.TermRepository;

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.inject.Inject;

import java.util.ArrayList;
import java.util.List;

@Service
public class DefaultCourseManager implements CourseManager
{
@Inject InstructorRepository instructorRepository;
@Inject CourseRepository courseRepository;
@Inject DepartmentRepository departmentRepository;
@Inject TermRepository termRepository;

@Override
@Transactional
public List<Instructor> getInstructors()
{
    return this.toList(this.instructorRepository.findAll());
}

@Override
@Transactional
public List<Course> getCourses()
{
    return this.toList(this.courseRepository.findAll());
}

@Override
@Transactional
public List<Department> getDepartments()
{
    return this.toList(this.departmentRepository.findAll());
}

private <E> List<E> toList(Iterable<E> i)
{
    List<E> list = new ArrayList<>();
    i.forEach(list::add);
    return list;
}

@Override
@Transactional
public void saveInstructor(Instructor instructor)
{
    this.instructorRepository.save(instructor);
}

@Override
@Transactional
public void saveCourse(Course course)
{
    this.courseRepository.save(course);
}

@Override
@Transactional
public void saveDepartment(Department department)
{
    this.departmentRepository.save(department);
}

@Override
@Transactional
public void saveTerm(Term term)
{
    this.termRepository.save(term);
}

@Override
@Transactional
public Term getTermById(Long id)
{
    return this.termRepository.findOne(id);
}

@Override
@Transactional
public Department getDepartmentByCode(String departmentCode)
{
    return this.departmentRepository.getOneByCode(departmentCode);
}

@Override
@Transactional
public Term getTermByCode(String termCode)
{
    return this.termRepository.getOneByCode(termCode);
}

@Override
@Transactional
public Instructor getInstructorByEmployeeId(String employeeId)
{
    return this.instructorRepository.getOneByEmployeeId(employeeId);
}

@Override
@Transactional
public Course getCourseByCrnAndTerm(String crn, long termId)
{
    return this.courseRepository.getOneByCrnAndTermId(crn, termId);
}

@Override
@Transactional
public long countCourses()
{
    return this.courseRepository.count();
}
}

包edu.ucdavis.dss.dw.site；
导入edu.ucdavis.dss.dw.entities.Course；
导入edu.ucdavis.dss.dw.entities.Department；
导入edu.ucdavis.dss.dw.entities.讲师；
导入edu.ucdavis.dss.dw.entities.Term；
导入edu.ucdavis.dss.dw.repositories.CourseRepository；
导入edu.ucdavis.dss.dw.repositories.DepartmentRepository；
导入edu.ucdavis.dss.dw.repositories.Instructor或repository；
导入edu.ucdavis.dss.dw.repositories.TermRepository；
导入org.springframework.stereotype.Service；
导入org.springframework.transaction.annotation.Transactional；
导入javax.inject.inject；
导入java.util.ArrayList；
导入java.util.List；
@服务
公共类DefaultCourseManager实现CourseManager
{
@注射讲师或保存讲师或保存员；
@注射CourseRepository CourseRepository；
@注入DepartmentRepository DepartmentRepository；
@注入术语库术语库；
@凌驾
@交易的
公共列表getInstructors（）
{
返回this.toList（this.instructorRepository.findAll（））；
}
@凌驾
@交易的
公开课程名单
{
返回this.toList（this.courseRepository.findAll（））；
}
@凌驾
@交易的
公共部门名单（
{
返回this.toList（this.departmentRepository.findAll（））；
}
私人名单收费表（Iterable i）
{
列表=新的ArrayList（）；
i、 forEach（列表：：add）；
退货清单；
}
@凌驾
@交易的
公共讲师（讲师讲师）
{
this.instructor repository.save（讲师）；
}
@凌驾
@交易的
公共课程（课程）
{
this.courseRepository.save（课程）；
}
@凌驾
@交易的
公共服务部（部门）
{
这个.departmentRepository.save（department）；
}
@凌驾
@交易的
公共无效保存期限（期限）
{
此.termRepository.save（术语）；
}
@凌驾
@交易的
公共术语getTermById（长id）
{
返回此.termRepository.findOne（id）；
}
@凌驾
@交易的
公共部门getDepartmentByCode（字符串departmentCode）
{
返回此.departmentRepository.getOneByCode（departmentCode）；
}
@凌驾
@交易的
公共术语getTermByCode（字符串termCode）
{
返回此.termRepository.getOneByCode（termCode）；
}
@凌驾
@交易的
公共讲师getInstructorByEmployeeId（字符串employeeId）
{
返回此.instructor repository.getOneByEmployeeId（employeeId）；
}
@凌驾
@交易的
公共课程getCourseByCrnAndTerm（字符串crn，长期ID）
{
返回此.courseRepository.getOneByCrnAndTermId（crn，termId）；
}
@凌驾
@交易的
公共长期课程（）
{
返回此.courseRepository.count（）；
}
}

您似乎偶然发现了Spring AOP抽象的一个经典问题。 虽然您已经用

@Transactional

注释了您的

persistBannerCourse

方法，但是您是从同一个类中调用它的。这意味着处理事务代码的代理永远不会被调用

查看相关的SO问题

最好的解决方案是重构代码并将

persistBannerCourse

移动到另一个类。

---

另一个解决方案是描述的

谢谢，这很有意义。我继续进行重构。我还发现可以使用TransactionTemplates，但这感觉有点太手动了。

package edu.ucdavis.dss.dw.site;

import edu.ucdavis.dss.dw.entities.Course;
import edu.ucdavis.dss.dw.entities.Department;
import edu.ucdavis.dss.dw.entities.Instructor;
import edu.ucdavis.dss.dw.entities.Term;
import edu.ucdavis.dss.dw.repositories.CourseRepository;
import edu.ucdavis.dss.dw.repositories.DepartmentRepository;
import edu.ucdavis.dss.dw.repositories.InstructorRepository;
import edu.ucdavis.dss.dw.repositories.TermRepository;

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.inject.Inject;

import java.util.ArrayList;
import java.util.List;

@Service
public class DefaultCourseManager implements CourseManager
{
@Inject InstructorRepository instructorRepository;
@Inject CourseRepository courseRepository;
@Inject DepartmentRepository departmentRepository;
@Inject TermRepository termRepository;

@Override
@Transactional
public List<Instructor> getInstructors()
{
    return this.toList(this.instructorRepository.findAll());
}

@Override
@Transactional
public List<Course> getCourses()
{
    return this.toList(this.courseRepository.findAll());
}

@Override
@Transactional
public List<Department> getDepartments()
{
    return this.toList(this.departmentRepository.findAll());
}

private <E> List<E> toList(Iterable<E> i)
{
    List<E> list = new ArrayList<>();
    i.forEach(list::add);
    return list;
}

@Override
@Transactional
public void saveInstructor(Instructor instructor)
{
    this.instructorRepository.save(instructor);
}

@Override
@Transactional
public void saveCourse(Course course)
{
    this.courseRepository.save(course);
}

@Override
@Transactional
public void saveDepartment(Department department)
{
    this.departmentRepository.save(department);
}

@Override
@Transactional
public void saveTerm(Term term)
{
    this.termRepository.save(term);
}

@Override
@Transactional
public Term getTermById(Long id)
{
    return this.termRepository.findOne(id);
}

@Override
@Transactional
public Department getDepartmentByCode(String departmentCode)
{
    return this.departmentRepository.getOneByCode(departmentCode);
}

@Override
@Transactional
public Term getTermByCode(String termCode)
{
    return this.termRepository.getOneByCode(termCode);
}

@Override
@Transactional
public Instructor getInstructorByEmployeeId(String employeeId)
{
    return this.instructorRepository.getOneByEmployeeId(employeeId);
}

@Override
@Transactional
public Course getCourseByCrnAndTerm(String crn, long termId)
{
    return this.courseRepository.getOneByCrnAndTermId(crn, termId);
}

@Override
@Transactional
public long countCourses()
{
    return this.courseRepository.count();
}
}