使用 Future 和 @Aync 时休眠两个开放会话

我正在尝试在我的应用程序中使用多线程来执行一些需要几分钟才能完成的任务。 我的想法是，我有 n 个对象，所以我希望并行处理这些对象，而不会让用户（网络应用程序）等待它们完成（因为这需要几分钟）。另外在其他情况下（当对象的数量为 1 时），我想等到该过程完成，以便用户可以看到结果。

但我有一些问题。

所以我的代码是： 运行一些任务服务Impl：

public class RunSomeTaskServiceImpl extends CommonService implements RunSomeTaskService{

    @Async
    @Override
        public Future<Response> doTasks(Student student) {
              Response response = new Response();
              //do Tasks
              return new AsyncResult<Response>(response);
           }
    }

运行一些任务服务：

public interface RunSomeTaskService{
    public Future<Response> doTasks(Student student);
}

学生服务设施：

@Autowired
RunSomeTaskService runSomeTaskService;

@Override
Transactional
public Response save(StudentBO[] students) throws Exception {
    ...
    for (StudentBO student : students) {
        ....
        Future<Response> response = runSomeTaskService.doTasks(student);
        if(students.size() == 1){
           return response.get();
        }
    }
....
}

因此，当有多个学生时，我会收到错误：

12:17:44.040 [DEMO-4] DEBUG o.h.r.t.b.j.i.JdbcResourceLocalTransactionCoordinatorImpl - JDBC transaction marked for rollback-only (exception provided for stack trace)
java.lang.Exception: exception just for purpose of providing stack trace
        at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.markRollbackOnly(JdbcResourceLocalTransactionCoordinatorImpl.java:265) [hibernate-core-5.0.6.Final.jar:5.0.6.Final]
        at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:156) [hibernate-core-5.0.6.Final.jar:5.0.6.Final]
        at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38) [hibernate-core-5.0.6.Final.jar:5.0.6.Final]
        at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:231) [hibernate-core-5.0.6.Final.jar:5.0.6.Final]
        at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:65) [hibernate-core-5.0.6.Final.jar:5.0.6.Final]
        at org.springframework.orm.hibernate5.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:581) [spring-orm-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:761) [spring-tx-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:730) [spring-tx-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:485) [spring-tx-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:291) [spring-tx-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) [spring-tx-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [spring-aop-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at org.springframework.aop.interceptor.AsyncExecutionInterceptor$1.call(AsyncExecutionInterceptor.java:108) [spring-aop-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at org.springframework.aop.interceptor.AsyncExecutionAspectSupport$CompletableFutureDelegate$1.get(AsyncExecutionAspectSupport.java:237) [spring-aop-4.2.4.RELEASE.jar:4.2.4.RELEASE]
        at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590) [na:1.8.0_171]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_171]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_171]
        at java.lang.Thread.run(Thread.java:748) [na:1.8.0_171]
12:17:44.043 [DEMO-4] DEBUG o.s.o.h.HibernateTransactionManager - Initiating transaction rollback after commit exception
org.hibernate.AssertionFailure: null id in com.app.model.FieldValue entry (don't flush the Session after an exception occurs)

当只有一个时：

org.hibernate.HibernateException: Illegal attempt to associate a collection with two open sessions. Collection : <unknown>
Collection contents: [[]]
        at org.hibernate.collection.internal.AbstractPersistentCollection.setCurrentSession(AbstractPersistentCollection.java:627)
        at org.hibernate.event.internal.OnUpdateVisitor.processCollection(OnUpdateVisitor.java:46)
        at org.hibernate.event.internal.AbstractVisitor.processValue(AbstractVisitor.java:104)
        at org.hibernate.event.internal.AbstractVisitor.processValue(AbstractVisitor.java:65)
        at org.hibernate.event.internal.AbstractVisitor.processEntityPropertyValues(AbstractVisitor.java:59)
        at org.hibernate.event.internal.AbstractVisitor.process(AbstractVisitor.java:126)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:293)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:227)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:92)
        at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
        at org.hibernate.internal.SessionImpl.fireSaveOrUpdate(SessionImpl.java:648)
        at org.hibernate.internal.SessionImpl.saveOrUpdate(SessionImpl.java:640)
        at org.hibernate.internal.SessionImpl.saveOrUpdate(SessionImpl.java:635)
        at com.app.dao.CommonDaoImpl.addOrUpdate(CommonDaoImpl.java:28)
        at com.app.services.ExtractDataServiceImpl.doExtraction(ExtractDataServiceImpl.java:361)
        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:498)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.interceptor.AsyncExecutionInterceptor$1.call(AsyncExecutionInterceptor.java:108)
        at org.springframework.aop.interceptor.AsyncExecutionAspectSupport$CompletableFutureDelegate$1.get(AsyncExecutionAspectSupport.java:237)
        at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)

学生模型

package com.app.model;
// Generated 18-jul-2018 15:27:32 by Hibernate Tools 5.2.10.Final

import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.UniqueConstraint;

/**
 * Student generated by hbm2java
 */
@Entity
@Table(name = "student", catalog = "school_db", uniqueConstraints = @UniqueConstraint(columnNames = "code"))
public class Student implements java.io.Serializable {

    private Integer id;
    private String name;
    private Grade grade;
    private Set<Subject> subjects = new HashSet<Subject>(0);

    public Student() {
    }


    @Id
    @GeneratedValue(strategy = IDENTITY)

    @Column(name = "id", unique = true, nullable = false)
    public Integer getId() {
        return this.id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "grade")
    public Grade getGrade() {
        return this.grade;
    }

    public void setGrade(Grade grade) {
        this.grade = grade;
    }

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "student")
    public Set<Subject> getSubjects() {
        return this.subjects;
    }

    public void setSubjects(Set<Subject> subjects) {
        this.subjects = subjects;
    }

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "student")
    public Set<Subject> getSubjects() {
        return this.subjects;
    }

}

spring-config.xml 文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:util="http://www.springframework.org/schema/util" 
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
  http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
  http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd
  http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
  http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
    <context:annotation-config  />
<!--    <context:component-scan base-package="com.app.controller, com.app.security" /> -->
<context:component-scan base-package="com.app.controller" />
    <tx:annotation-driven transaction-manager="transactionManager"/>
    <mvc:annotation-driven />
....
<bean id="sessionFactory"
        class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="annotatedClasses">
            <list>
                <value>com.app.model.Student</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
                <prop key="hibernate.show_sql">true</prop>
            </props>
        </property>
    </bean>

    <bean id="transactionManager"
        class="org.springframework.orm.hibernate5.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>
...

那么你能帮我避免这个问题吗？