Hibernate: не удалось получить сеанс с синхронизацией транзакций для текущего потока] с первопричиной

Question

Я новичок в Spring и Hibernate. Я создаю приложение Spring, которое извлекает данные из базы данных и передает их в формате json. Всякий раз, когда я запускаю приложение, я получаю сообщение Не удалось получить сеанс с синхронизацией транзакций для текущего потока . Если я добавлю настройки гибернации в файл springconfig.xml, приложение будет работать нормально. Если я храню их отдельно, я получаю ошибку ниже.

Ниже мой Stacktrace

SEVERE: Servlet.service() for servlet [port] in context with path [/port] threw exception [Request processing failed; nested exception is org.hibernate.HibernateException: Could not obtain transaction-synchronized Session for current thread] with root cause 
org.hibernate.HibernateException: Could not obtain transaction-synchronized Session for current thread
at org.springframework.orm.hibernate5.SpringSessionContext.currentSession(SpringSessionContext.java:143)
at org.hibernate.internal.SessionFactoryImpl.getCurrentSession(SessionFactoryImpl.java:496)
at com.port.domain.dao.DomainDAOImpl.getDomains(DomainDAOImpl.java:39)
at com.port.domain.service.DomainServiceImpl.getDomains(DomainServiceImpl.java:21)
at com.port.domain.controller.DomainRestController.getDomains(DomainRestController.java:23)
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.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:668)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

Я попробовал ответ, предоставленный itachi по этой ссылке Spring Hibernate - Не удалось получить сеанс с синхронизацией транзакций для текущего потока . Но, кажется, это обходной путь. Сессия не будет закрыта автоматически. Ниже мой код

Класс My Entity (DomainList.java):

package com.port.domain.model;

import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import org.springframework.stereotype.Component;

@Entity
@Table(name="domainlist")
@Component
public class DomainList {

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name="domainID")
private int domainID;

@Column(name="domainName")
private String domainName;

@Column(name="currentPrice")
private float currentPrice;

public int getDomainID() {
    return domainID;
}
public void setDomainID(int domainID) {
    this.domainID = domainID;
}

public String getDomainName() {
    return domainName;
}
public void setDomainName(String domainName) {
    this.domainName = domainName;
}

public float getCurrentPrice() {
    return currentPrice;
}
public void setCurrentPrice(float currentPrice) {
    this.currentPrice = currentPrice;
}

@Override
public String toString() {
    return "DomainList [domainID=" + domainID + ", domainName=" + domainName + ",  currentPrice=" + currentPrice + "]";
}   

}

Мой RestContoller (DomainRestComtroller.java):

package com.port.domain.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.port.domain.model.DomainList;
import com.port.domain.service.DomainService;


@RestController
public class DomainRestController {

@Autowired
private DomainService domainService;

@RequestMapping(value="/getDomains", method=RequestMethod.GET, headers="Accept=application/json")
public List<DomainList> getDomains() {
    List<DomainList> domainList = domainService.getDomains();
    return domainList ;

    }   

}

Мой класс обслуживания (DomainServiceImpl.java):

package com.port.domain.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.port.domain.dao.DomainDAO;
import com.port.domain.model.DomainList;

@Service
public class DomainServiceImpl implements DomainService {

@Autowired
private DomainDAO domainDAO;

@Override
@Transactional
public List<DomainList> getDomains() {
    return domainDAO.getDomains();
    }

}

Мой класс DAO (DomainDAOImpl.java):

package com.port.domain.dao;

import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.query.Query;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.orm.hibernate5.HibernateTemplate;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import com.port.domain.model.DomainList;

@Repository
public class DomainDAOImpl implements DomainDAO {

@Autowired
private SessionFactory sessionFactory;

@Override
public List<DomainList> getDomains() {
    Session currentSession = sessionFactory.getCurrentSession();

    Query<DomainList> theQuery = 
            currentSession.createQuery("from DomainList", DomainList.class);

    List<DomainList> Domains = theQuery.getResultList();

    for (DomainList domain : Domains)
        System.out.println(domain.toString());
    return Domains;
    }

}

My springconfig.xml:

<?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:tx="http://www.springframework.org/schema/tx"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
    http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
    http://www.springframework.org/schema/tx  http://www.springframework.org/schema/tx/spring-tx.xsd">

<context:annotation-config />

<mvc:annotation-driven/>

<!-- For the Stereotype annotations to work -->
<context:component-scan
    base-package="com.port.domain.controller" />
<context:component-scan
    base-package="com.port.domain.dao" />
<context:component-scan
    base-package="com.port.domain.model" />
<context:component-scan
    base-package="com.port.domain.service" />

Мой hibernate.cfg.xml:

<?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:tx="http://www.springframework.org/schema/tx"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
    http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd
    http://www.springframework.org/schema/mvc
    http://www.springframework.org/schema/mvc/spring-mvc.xsd
    http://www.springframework.org/schema/tx 
    http://www.springframework.org/schema/tx/spring-tx.xsd">

<bean id="myDataSource"
    class="com.mchange.v2.c3p0.ComboPooledDataSource">
    <property name="driverClass" value="com.mysql.jdbc.Driver" />
    <property name="jdbcUrl"
        value="jdbc:mysql://localhost:3306/port" />
    <property name="user" value="username" />
    <property name="password" value="password" />

    <!-- these are connection pool properties for C3P0 -->
    <property name="initialPoolSize" value="5" />
    <property name="minPoolSize" value="5" />
    <property name="maxPoolSize" value="20" />
    <property name="maxIdleTime" value="30000" />
</bean>

<bean id="sessionFactory"
    class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
    <property name="dataSource" ref="myDataSource" />
    <property name="packagesToScan"
        value="com.port.domain.model" />
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
            <prop key="hibernate.show_sql">true</prop>
        </props>
    </property>
</bean>
<bean id="myTransactionManager"
    class="org.springframework.orm.hibernate5.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

<!-- Step 4: Enable configuration of transactional behavior based on annotations -->
<tx:annotation-driven transaction-manager="myTransactionManager"/>


<mvc:resources location="/resources/"
    mapping="/resources/**"></mvc:resources>
</beans>

Мой web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

<display-name>SpringMvcRestHibernate</display-name>

<servlet>
    <servlet-name>port</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/springconfig.xml</param-value>        
    </init-param>
</servlet>

<servlet-mapping>
    <servlet-name>port</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

<!-- Database configuration file -->
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/hibernate.cfg.xml</param-value>
</context-param>

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
</web-app>

В соответствии с моим пониманием, это должно работать нормально после просмотра многих примеров такого рода. Но я не понимаю, почему я получаю ошибку.