Создание экземпляра EntityManager через Spring

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Создание экземпляра EntityManager через Spring

Post author:admin
Запись опубликована:15 апреля, 2023
Post category:Вопросы по программированию

#java #spring #hibernate #hsqldb #entitymanager

#java #spring #переход в спящий режим #hsqldb #entitymanager

Вопрос:

Я использую entity manager в своем spring 3.2.2 приложении на базовом hsqld:

 @Transactional
public class TestDaoImpl implements PersonDao {

    /**
     * Logger
     */
    private static final Logger log = Logger.getLogger(TestDaoImpl.class);

    @PersistenceContext    
    private EntityManager em;

    /**
     * @param em
     */
    public TestDaoImpl() {
        super();
    }

    @Override
    public List<Person> getAll() {
        log.info("get all DAO");

        //TODO fix query!!!
        List<Person> resultList = em.createQuery("SELECT * FROM Person;", Person.class).getResultList(); 

        log.info(resultList.toString());

        return resultList;

    }
}

Мои pom.xml зависимости:

 <dependencies>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>4.2.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>3.2.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>3.2.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>3.2.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.hsqldb</groupId>
            <artifactId>hsqldb</artifactId>
            <version>2.3.2</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-tools</artifactId>
            <version>3.2.0.ga</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-annotations</artifactId>
            <version>3.5.6-Final</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.6.4</version>
        </dependency>
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
            <version>1.4</version>
        </dependency>
    </dependencies>

Моя проблема в том, что my EntityManager em равно нулю. Следовательно, диспетчер сущностей не внедряется spring. Вот контекст моего приложения:

 <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:security="http://www.springframework.org/schema/security"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/aop
                        http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
                        http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-3.2.xsd
                        http://www.springframework.org/schema/tx
                        http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">

    <tx:annotation-driven />
    <context:annotation-config />

    <bean id="mainGUI" class="com.testApp.MainWindow" />

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="org.hsqldb.jdbcDriver" />
        <property name="url" value="jdbc:hsqldb:hsql://localhost/testDB" />
        <property name="username" value="sa" />
        <property name="password" value="" />
        <property name="initialSize" value="5" />
        <property name="maxActive" value="10" />
    </bean>

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="persistenceUnitName" value="jpaData" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
        </property>
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.HSQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">false</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>
</beans>

Any recommendations why my application context does not get instantiated? Spring and hibernate load correctly!

UPDATE

I changed my class to:

 @Transactional
@Repository
public class TestDaoImpl implements PersonDao {

    private static final Logger log = Logger.getLogger(PersonDaoImpl.class);

    @PersistenceContext    
    public EntityManager em;

    public TestDaoImpl() {
        super();
    }

    @Override
    public List<Person> getAll() {
        log.info("get all DAO");

        //TODO fix query!!!
        List<Person> resultList = em.createQuery("SELECT * FROM Person;", Person.class).getResultList(); 

        log.info(resultList.toString());

        return resultList;

    }
}

However, I still get the exception java.lang.NullPointerException at:

em.createQuery("SELECT * FROM Person;", Person.class).getResultList();

The debugger shows that, em is still null.

Обновить

Мой файл журнала:

 0    [main] INFO  com.Application.main.startGUI  - set look and feel
775  [main] INFO  org.springframework.context.support.ClassPathXmlApplicationContext  - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@291aff: startup date [Thu Jul 03 10:22:25 CEST 2014]; root of context hierarchy
854  [main] INFO  org.springframework.beans.factory.xml.XmlBeanDefinitionReader  - Loading XML bean definitions from class path resource [applicationContext.xml]
1383 [main] INFO  org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean  - Building JPA container EntityManagerFactory for persistence unit 'jpaData'
1546 [main] INFO  org.hibernate.annotations.common.Version  - HCANN000001: Hibernate Commons Annotations {4.0.1.Final}
1551 [main] INFO  org.hibernate.Version  - HHH000412: Hibernate Core {4.2.0.Final}
1553 [main] INFO  org.hibernate.cfg.Environment  - HHH000206: hibernate.properties not found
1554 [main] INFO  org.hibernate.cfg.Environment  - HHH000021: Bytecode provider name : javassist
1576 [main] INFO  org.hibernate.ejb.Ejb3Configuration  - HHH000204: Processing PersistenceUnitInfo [
    name: jpaData
    ...]
1859 [main] INFO  org.hibernate.service.jdbc.connections.internal.ConnectionProviderInitiator  - HHH000130: Instantiating explicit connection provider: org.hibernate.ejb.connection.InjectedDataSourceConnectionProvider
2593 [main] INFO  org.hibernate.dialect.Dialect  - HHH000400: Using dialect: org.hibernate.dialect.HSQLDialect
2624 [main] INFO  org.hibernate.engine.transaction.internal.TransactionFactoryInitiator  - HHH000268: Transaction strategy: org.hibernate.engine.transaction.internal.jdbc.JdbcTransactionFactory
2630 [main] INFO  org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory  - HHH000397: Using ASTQueryTranslatorFactory
2971 [main] INFO  org.hibernate.tool.hbm2ddl.SchemaUpdate  - HHH000228: Running hbm2ddl schema update
2971 [main] INFO  org.hibernate.tool.hbm2ddl.SchemaUpdate  - HHH000102: Fetching database metadata
2975 [main] INFO  org.hibernate.tool.hbm2ddl.SchemaUpdate  - HHH000396: Updating schema
3002 [main] INFO  org.hibernate.tool.hbm2ddl.TableMetadata  - HHH000261: Table found: PUBLIC.PUBLIC.READATA
3002 [main] INFO  org.hibernate.tool.hbm2ddl.TableMetadata  - HHH000037: Columns: [budgetednetrentalrevenuespernetsalesrevenues, marketrisklevel, installmentsontotalfacilityineurforyear10, totcom_9, totcom_8, totcom_7, customer, city, cashcollateral, leasecontractcurrency, cncy, projnr, maturitydate, usetype, totalnla, userisklevel, actualnetrentalrevenuespernetsalesrevenues, country, gccnr, che, market, totcom_10, percentagerentalincomeforyear8, percentagerentalincomeforyear7, avbinc_10, percentagerentalincomeforyear9, percentagerentalincomeforyear4, percentagerentalincomeforyear3, percentagerentalincomeforyear6, tic_contractcurrency, percentagerentalincomeforyear5, installmentsontotalfacilityincontractcurrencyforyear10, percentagerentalincomeforyear2, percentagerentalincomeforyear1, defaultrisklevel, avbinc_7, avbinc_6, installmentsontotalfacilityincontractcurrencyforyear9, avbinc_9, installmentsontotalfacilityincontractcurrencyforyear8, avbinc_8, installmentsontotalfacilityincontractcurrencyforyear7, avbinc_3, installmentsontotalfacilityincontractcurrencyforyear6, avbinc_2, installmentsontotalfacilityincontractcurrencyforyear5, avbinc_5, avbinc_4, installmentsontotalfacilityincontractcurrencyforyear4, installmentsontotalfacilityincontractcurrencyforyear3, externalcommitment, installmentsontotalfacilityincontractcurrencyforyear2, avbinc_1, installmentsontotalfacilityincontractcurrencyforyear1, id, installmentsontotalfacilityineurforyear8, installmentsontotalfacilityineurforyear7, installmentsontotalfacilityineurforyear9, locqual, repaysou, marketvalue_contractcurrency, installmentsontotalfacilityineurforyear1, installmentsontotalfacilityineurforyear2, refinancingrate, installmentsontotalfacilityineurforyear5, installmentsontotalfacilityineurforyear6, installmentsontotalfacilityineurforyear3, installmentsontotalfacilityineurforyear4, actualnla, externalcommitmentinpecentage, projstat, totcom_1, totcom_2, percentagerentalincomeforyear10, totcom_3, totcom_4, projectstatusrisklevel, totcom_5, totcom_6]
3002 [main] INFO  org.hibernate.tool.hbm2ddl.TableMetadata  - HHH000108: Foreign keys: []
3002 [main] INFO  org.hibernate.tool.hbm2ddl.TableMetadata  - HHH000126: Indexes: [sys_idx_sys_pk_10114_10115]
3006 [main] INFO  org.hibernate.tool.hbm2ddl.TableMetadata  - HHH000261: Table found: PUBLIC.PUBLIC.SCENARIOBASE
3006 [main] INFO  org.hibernate.tool.hbm2ddl.TableMetadata  - HHH000037: Columns: [id, others, see, year, cee, we]
3006 [main] INFO  org.hibernate.tool.hbm2ddl.TableMetadata  - HHH000108: Foreign keys: []
3007 [main] INFO  org.hibernate.tool.hbm2ddl.TableMetadata  - HHH000126: Indexes: [sys_idx_sys_pk_10117_10118]
3007 [main] INFO  org.hibernate.tool.hbm2ddl.SchemaUpdate  - HHH000232: Schema update complete
3068 [main] INFO  org.springframework.beans.factory.support.DefaultListableBeanFactory  - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@7a1576: defining beans [org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,personBaseDaoImpl,mainGUI,dataSource,entityManagerFactory,transactionManager,entityManager,org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor#0,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchy
3402 [AWT-EventQueue-0] INFO  com.Application.gui.personSelection.MainWindow  - make Layout
3402 [AWT-EventQueue-0] INFO  com.Application.gui.personSelection.MainWindow  - add Menue Bar
3413 [AWT-EventQueue-0] INFO  com.Application.gui.personSelection.MainWindow  - add Tab Bar
3416 [AWT-EventQueue-0] INFO  com.Application.gui.personSelection.MainTabPanel  - enterMainTabPanel create Layout method
3420 [AWT-EventQueue-0] INFO  com.Application.gui.personSelection.PersonSelectionPanel  - enter placeSelectionWithButtons method
3511 [AWT-EventQueue-0] INFO  com.Application.gui.accronData.GUITabPanel  - enter GUITabPanel create Layout method
3514 [AWT-EventQueue-0] INFO  com.Application.service.PersonBaseServiceImpl  - reveiving all data in the person base service
3514 [AWT-EventQueue-0] INFO  com.Application.dao.PersonBaseDaoImpl  - get all DAO
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at com.Application.dao.PersonBaseDaoImpl.getAll(PersonBaseDaoImpl.java:51)
    at com.Application.service.PersonBaseServiceImpl.getAll(PersonBaseServiceImpl.java:45)
    at com.Application.gui.accronData.GUIDataPanel.<init>(GUIDataPanel.java:42)
    at com.Application.gui.accronData.GUITabPanel.createLayout(GUITabPanel.java:42)
    at com.Application.gui.personSelection.MainWindow.createTabBar(MainWindow.java:159)
    at com.Application.gui.personSelection.MainWindow.makeLayout(MainWindow.java:182)
    at com.Application.gui.personSelection.MainWindow.access$1(MainWindow.java:173)
    at com.Application.gui.personSelection.MainWindow$4.run(MainWindow.java:196)
    at java.awt.event.InvocationEvent.dispatch(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$400(Unknown Source)
    at java.awt.EventQueue$2.run(Unknown Source)
    at java.awt.EventQueue$2.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

Обновить

Мой PersonBaseServiceImpl :

 public class PersonBaseServiceImpl implements PersonBaseService {

    /**
     * Logger
     */
    private static final Logger log = Logger.getLogger(PersonBaseServiceImpl.class);

    /**
     * PersonBaseDAO Access
     */
    private TestDao testBaseDAO; // TestDao is an interface to my TestDaoImpl class

    /**
     * Constructor
     * @param scenarioBaseDAO
     */
    public PersonBaseServiceImpl(){
        this.testBaseDAO = new TestDaoImpl();

    }

    @Override
    public List<PersonBase> getAll() {
        log.info("reveiving all data in the scenario base service");

        return testBaseDAO.getAll();
    }

}

1. Как TestDaoImpl используется? Вы внедряете это в тест? Если да, то каким образом?

2. @geoand Спасибо за ваш ответ! Я в основном создаю экземпляр на уровне сервиса. Пожалуйста, посмотрите мой файл журнала! Я также отладил свое приложение и обнаружил, что em равно нулю, поэтому запрос, который я хочу создать в моей базе данных, не может быть использован;(. Я действительно ценю ваш ответ!

3. Не могли бы вы, пожалуйста, опубликовать PersonBaseServiceImpl ?

4. @geoand Спасибо за ваш ответ! Пожалуйста, посмотрите мое последнее обновление.

Ответ №1:

Проблема в том, что вы создаете экземпляр PersonBaseDao самостоятельно (используя new ), и это для того, чтобы позволить Spring управлять его жизненным циклом.

Вам нужно использовать @Autowired на PersonBaseDao и создать PersonBaseServiceImpl управляемый компонент Spring, используя аннотацию стереотипа (вероятно @Service ).

То же самое, конечно, относится и к способу использования PersonBaseServiceImpl внутри любого компонента, вызывающего его

Ответ №2:

Вам не хватает @Repository аннотации в вашем DAO.

1. Должен ли я заменить @Transactional аннотацию на @Repository annotation?

2. Могу ли я также использовать @Component вместо двух вышеуказанных? Я действительно ценю ваш ответ!

3. @Vivien Нет, вы можете добавить обе аннотации

4. @Vivien Plaese добавьте также ‘<context:component-scan base-package=»your.package»/>` к контексту вашего приложения.

5. @Vivien есть ли какие-либо исключения в файле журнала при запуске вашего приложения