注解和Hibernate拦截器

Question

注解和Hibernate拦截器

7

我正在将一个应用从Hibernate的XML配置迁移到注解。我不确定如何将BusinessObjectInterceptor类适配到新的基于注解的格式中。

我们正在改变HibernateUtil类来创建SessionFactory。

            InitialContext ctx      = new InitialContext();
        sessionFactory  = (SessionFactory)ctx.lookup("java:/hibernate/SessionFactory");

创建EntityManagerFactory

            entityManagerFactory = Persistence.createEntityManagerFactory("primary");

我们正在将HibernateUtil类从使用sessionFactory.openSession()更改为从EntityManager创建会话。

            //s = sessionFactory.openSession(new BusinessObjectInterceptor());
        EntityManager entityManager = entityManagerFactory.createEntityManager();
        s = entityManager.unwrap(Session.class);

问题在于我不确定如何将BusinessObjectInterceptor注入到一个新的Hibernate Session中，或者注释我的类的正确方式，以便它们可以使用该拦截器。

我试图在persistence.xml文件中将拦截器设置为属性，但我不确定这是否正确。

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
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_2_0.xsd">
   <persistence-unit name="primary"><jta-data-source>java:jboss/datasources/MySqlDS</jta-data-source>

  <properties>
     <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
     <property name="hibernate.ejb.interceptor.session_scoped" value="com.mycompany.common.persistence.BusinessObjectInterceptor"/>
           </properties>

我们以前是通过hbm.xml文件来配置我们的类。

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class name="com.mycompany.liveexpert.common.businessobjects.ServerSettings" table="server_settings">
            <id name="serverSettingsID" type="integer" column="server_settings_id"> 
                    <generator class="identity" />
            </id>
            <version  name="updateCounter" column="update_counter"/>
            <property name="changedDate" type="timestamp" column="changed_date"/>
            <property name="changedBy" type="string" column="changed_by"/>
            <property name="createdDate" type="timestamp" column="created_date"/>
            <property name="createdBy" type="string" column="created_by"/>
            <property name="status" type="string" column="status"/>

            <property name="emailServer" type="string" column="email_server"   />
            <property name="emailFromAddress" type="string" column="email_from_address"   />
            <property name="emailUser" type="string" column="email_user"   />
            <property name="emailPassword" type="string" column="email_password"   />

</class>

注释类看起来像这样：

@Entity
@Table(name="server_settings")
public class ServerSettings  extends BusinessObject
{
    @Id @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer serverSettingsID;
    @Column(name = "email_server")
    private String emailServer;
    @Column(name = "email_from_address")
private String emailFromAddress;
    @Column(name = "email_user")
private String emailUser;
    @Column(name = "email_password")
private String emailPassword;

我们有一个BusinessObjectInterceptor类和一个BusinessObject类。为方便参考，我会在下面发布它们的代码。我认为需要做的是对BusinessObject类进行注释，但我不确定如何操作，因为BusinessObject类并不映射到特定表中的列，而是映射到我们数据库中所有表中共同的列。我将在下面粘贴这两个类。欢迎提供如何使用注释配置我的拦截器的任何建议。谢谢。

BusinessObjectInterceptor：

public class BusinessObjectInterceptor extends EmptyInterceptor
{
private int updates;
private int creates;

private static final String defaultDesignation = "system";

private String getUserDesignation()
{
    UserContextI theContext = PersistenceContext.getUserContext();
    if (theContext == null) return defaultDesignation;
    String uid = theContext.getUserDesignation();
    if (uid == null) return defaultDesignation;
    return uid;
}
public boolean onFlushDirty(Object entity,
                            Serializable id,
                            Object[] currentState,
                            Object[] previousState,
                            String[] propertyNames,
                            Type[] types)
{
    boolean theReturn = false;
    if (entity instanceof BusinessObject)
    {
        updates++;
        for (int i=0; i<propertyNames.length; i++)
        {
            if ("changedDate".equals(propertyNames[i]))
            {
                currentState[i] = new Date();
                theReturn = true;
            }
            if ("changedBy".equals(propertyNames[i]))
            {
                currentState[i] = getUserDesignation();
                theReturn = true;
            }
        }
    }
    return theReturn;
}
public boolean onSave(Object entity,
        Serializable id,
        Object[] state,
        String[] propertyNames,
        Type[] types)
{
    boolean theReturn = false;
    if (entity instanceof BusinessObject)
    {
        creates++;
        for (int i=0; i<propertyNames.length; i++)
        {
            if ("createdDate".equals(propertyNames[i]))
            {
                state[i] = new Date();
                theReturn = true;
            }
            if ("createdBy".equals(propertyNames[i]))
            {
                state[i] = getUserDesignation();
                theReturn = true;
            }
            if ("changedDate".equals(propertyNames[i]))
            {
                state[i] = new Date();
                theReturn = true;
            }
            if ("changedBy".equals(propertyNames[i]))
            {
                state[i] = getUserDesignation();
                theReturn = true;
            }
        }
    }
    return theReturn;
}
public void preFlush(Iterator entities)
{
    updates = 0;
    creates = 0;
}

BusinessObject

    public abstract class BusinessObject
{
private String status;
private String createdBy;
private Date   createdDate;
private String changedBy;
private Date   changedDate;
private int    updateCounter;

/**
 * Generic save method to be used for persisting a business object.
 * 
 * @return a copy of this business object in its saved state.
 * 
 * @throws Exception
 */
public BusinessObject save() throws Exception 
{
    Session        hsession = null;
    Transaction    tx = null;
    BusinessObject theObject = null;

    validate(); // throws ValidationException

    try {
        hsession = HibernateUtil.currentSession();
        tx = hsession.beginTransaction();

        if (getStatus() == null || getStatus().length() < 1)
        {
            setStatus("OK");
        }

        //theObject = (BusinessObject) hsession.saveOrUpdateCopy(this);
        theObject = (BusinessObject) hsession.merge(this);
        if (tx != null && tx.isActive() && !tx.wasCommitted())
            tx.commit();
    } catch (Exception e){
        try
        {
        if (tx!=null) tx.rollback();
        } catch (Exception e3)
        {}
        try
        {
        hsession.close();
        } catch (Exception e2)
        {}
        throw e;
    } finally
    {
        HibernateUtil.closeSession();
    }
    return theObject;
}

- user619804

可能是重复的问题：使用Spring注解自动应用Hibernate拦截器？ - Don Roby

这个问题中可能有一些信息可以帮助我，但是我没有使用Spring，所以它并不完全适用。 - user619804

好的。我无法撤回我的关闭投票，但如果它关闭了，我会投票重新开放。 - Don Roby

1个回答

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- Zoran Regvart · Accepted Answer

在JPA中，您可以使用@PrePersist和@PreUpdate注释来注释您的模型（@Entity类）中的方法，这些方法将在持久化(INSERT)或更新(UPDATE)之前被调用。

您可以创建一个实体监听器，并向您的模型添加@EntityListeners注释。

public class BusinessListener {
    @PrePersist
    public void businessUpdate(BusinessObject obj) {
        obj.setCreatedDate(new Date());
        ....
    }
    @PreUpdate
    public void businessUpdate(BusinessObject obj) {
        obj.setChangedDate(new Date());
        ....
    }
}

@EntityListeners(class=...BusinessListener)
public class BusinessObject {
}

或者你可以将方法放在一个基础实体类中，并从中扩展所有的实体，例如：

public class BusinessObject {
    @PrePersist
    public void businessUpdate() {
        createdDate = new Date();
        ....
    }
    @PreUpdate
    public void businessUpdate() {
        changedDate = new Date();
        ....
    }
}