使用SpringFramework，EntityManager始终为NULL

时间：2012-02-16 10:33:24

标签： java spring entitymanager

美好的一天，

我一直在研究Maven + Spring + Hibernate项目。实际上，这只是一个测试项目，只是为了熟悉Spring如何使用Hibernate（+ Maven）。我已经设置并准备了必要的依赖项。即Spring的appcontext.xml，Hibernate的persistence.xml，JPA / Persistence / Hibernate的实体和DAO对象。

在调试期间，观察到EntityManager始终为null。我不知道是什么造成了这个因为我已经完成了ff：

  1. 在我的控制器上自动装配
  2. 在applicationContext.xml
    3. 上将其声明为bean
  3. 将我的DAO对象注释为@Repository
  4. 在entityManagerFactory
    5. 上定义transactionManager，vendorAdapter和applicationContext.xml作为bean

    我一直在调试和尝试变通办法。不幸的是，我还没有解决这个问题。希望有人能对这个问题有所了解。

    以下是我的项目的代码和配置：

    ＆lt; --- persistence.xml ---＆gt; 

    <persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">
    <persistence-unit name="msh" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <class>com.msh.TblFileinfo</class>
    </persistence-unit>
</persistence>

    ＆lt; --- applicationContext.xml ---＆gt; 

    <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:lang="http://www.springframework.org/schema/lang"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
           http://www.springframework.org/schema/tx
           http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-3.0.xsd
           http://www.springframework.org/schema/lang
           http://www.springframework.org/schema/lang/spring-lang-3.0.xsd
           http://www.springframework.org/schema/security">

    <!-- need to create database.properties file -->
    <context:property-placeholder location="classpath:database.properties"/>

    <context:component-scan base-package="com.msh"/>

    <!-- tell Spring that it should act on any @PersistenceContext and @Transactional annotations found in bean classes -->
    <!-- <tx:annotation-driven/> -->
    <tx:annotation-driven transaction-manager="transactionManager"/>

    <bean class="com.msh.TblFileinfoHome" />
    <bean class="com.msh.TblFileinfo" />

    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

    <bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
        <!-- <property name="databasePlatform" value="${platform}" /> -->
        <property name="showSql" value="${database.showSql}" />
        <property name="generateDdl" value="${database.generateDdl}" />
    </bean>

    <bean id="entityManagerFactory" class="org.org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceUnitName" value="msh" />
        <property name="dataSource" ref="dataSource" />
        <!-- <property name="loadTimeWeaver" class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver" /> -->
        <property name="jpaVendorAdapter" ref="jpaVendorAdapter" />
    </bean>

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

    <bean  id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${database.driverClassName}" />
        <property name="url" value="${database.url}" />
        <property name="username" value="${database.username}" />
        <property name="password" value="${database.password}" />
    </bean>
</beans>

    ＆lt; ---主要java代码---＆gt; 

    package com.msh;

public class MavenSpringHibernate {

    /**
     * @param args
     */

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Sample s = new Sample();
        s.persist();
    }
}

    ＆lt; --- DAO ---＆gt; 

    package com.msh;

import javax.ejb.Stateless;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityManager;
import javax.persistence.Persistence;
import javax.persistence.PersistenceUnit;
import javax.persistence.PersistenceContext;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Home object for domain model class TblFileinfo.
 * @see com.trendmicro.grid.mshPackage.TblFileinfo
 * @author Hibernate Tools
 */

/**
@Stateless
@Repository
@Transactional
*/

@Repository
public class TblFileinfoHome {

    private static final Log log = LogFactory.getLog(TblFileinfoHome.class);

    @PersistenceContext(unitName="msh")
    private EntityManager entityManager;

    @Transactional
    public void persist(TblFileinfo transientInstance) {
        log.debug("persisting TblFileinfo instance");
        try {
            entityManager.persist(transientInstance);
            log.debug("persist successful");
        }
        catch (RuntimeException re) {
            log.error("persist failed", re);
            throw re;
        }
    }

    @Transactional
    public void remove(TblFileinfo persistentInstance) {
        log.debug("removing TblFileinfo instance");
        try {
            entityManager.remove(persistentInstance);
            log.debug("remove successful");
        }
        catch (RuntimeException re) {
            log.error("remove failed", re);
            throw re;
        }
    }

    @Transactional
    public TblFileinfo merge(TblFileinfo detachedInstance) {
        log.debug("merging TblFileinfo instance");
        try {
            TblFileinfo result = entityManager.merge(detachedInstance);
            log.debug("merge successful");
            return result;
        }
        catch (RuntimeException re) {
            log.error("merge failed", re);
            throw re;
        }
    }

    @Transactional
    public TblFileinfo findById( Long id) {
        log.debug("getting TblFileinfo instance with id: " + id);
        try {
            TblFileinfo instance = entityManager.find(TblFileinfo.class, id);
            log.debug("get successful");
            return instance;
        }
        catch (RuntimeException re) {
            log.error("get failed", re);
            throw re;
        }
    }
}

    ---实体--- 

    package com.msh;


import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;

import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.Table;

/**
 * TblFileinfo generated by hbm2java
 */
@Entity
@Table(name="tbl_fileinfo"
    ,catalog="behavior"
)
public class TblFileinfo  implements java.io.Serializable {


     private Long fileId;
     private String filename;
     private String filetype;

    public TblFileinfo() {
    }

    public TblFileinfo(String filename, String filetype) {
       this.filename = filename;
       this.filetype = filetype;
    }

     @Id @GeneratedValue(strategy=GenerationType.AUTO)


    @Column(name="file_id", unique=true, nullable=false)
    public Long getFileId() {
        return this.fileId;
    }

    public void setFileId(Long fileId) {
        this.fileId = fileId;
    }


    @Column(name="filename", length=200)
    public String getFilename() {
        return this.filename;
    }

    public void setFilename(String filename) {
        this.filename = filename;
    }


    @Column(name="filetype", length=50)
    public String getFiletype() {
        return this.filetype;
    }

    public void setFiletype(String filetype) {
        this.filetype = filetype;
    }
}

    ＆lt; ---样本类控制器---＆gt; 

    package com.msh;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Transactional;
import com.trendmicro.grid.msh.TblFileinfo;
import com.trendmicro.grid.msh.TblFileinfoHome;


@Transactional
public class Sample {
    @Autowired
    private TblFileinfo tinfo;
    private TblFileinfoHome tinfoh;

    public Sample()
    {
        tinfo = new TblFileinfo("c:/jayson/murillo/pryde.exe", "uv_win32");
        tinfoh = new TblFileinfoHome();
    }

    public void persist()
    {
        tinfoh.persist(tinfo);
    }
}

    再次希望有人能就此提供反馈。提前谢谢！

2 个答案:

答案 0 :(得分：2)

你甚至没有开始春天！

Sample s = new Sample();

Sample是一个Spring bean。您必须首先启动应用程序上下文并从那里获取bean。请参阅@ nico_ekito的回答：

public static void main(String[] args) {
    ApplicationContext context =
         new ClassPathXmlApplicationContext("classpath:/applicationContext.xml");
    Sample s = context.getBean(Sample.class);
    s.persist();
}

一旦启动上下文（可能会导致一些错误），请更正以下内容：

  • 删除它：

    tinfoh = new TblFileinfoHome();

    注释字段：

    @Autowired
private TblFileinfoHome tinfoh;

  • 您不应该自动装配实体类：

    @Autowired                //remove this annotation
private TblFileinfo tinfo;

答案 1 :(得分：2)

您不在主类中加载Spring上下文：

public class MavenSpringHibernate {

    /**
     * @param args
     */

    public static void main(String[] args) {

        ApplicationContext context =
                new ClassPathXmlApplicationContext(new String[] {"classpath:/PATH/TO/applicationContext.xml"});

        Sample s = context.getBean(Sample.class);
        s.persist();
    }
}
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