Question

我在Web应用程序中创建了Entity，DAo和Façade。我的代码没有错误但是在使用JPA的find（T.class，id）方法时我得到了这个异常。它还说我的实体上没有@Entity注释。但事实并非如此。如何解决这个问题。

myEntity所

@Entity
@Table(name = "uyeler")
public class Uyeler implements Serializable {

private static final long serialVersionUID = 1L;

@Id
@Column(name = "kullaniciadi")
private String kullaniciadi;

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

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

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

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

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

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

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

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

public String getKullaniciadi() {
    return kullaniciadi;
}

MyDaoImpl;

public abstract class UyelerDaoImpl<T> {

private final static String UNIT_NAME ="KutuphaneOtomasyonuEJB";

@PersistenceUnit(unitName = UNIT_NAME)    
private EntityManagerFactory emf = javax.persistence.Persistence.createEntityManagerFactory(UNIT_NAME);
private EntityManager em = emf.createEntityManager(); 

public Uyeler findMemberByUserName(String username){
    return  em.find(Uyeler.class, username);
}

}

的persistence.xml

<persistence-unit name="KutuphaneOtomasyonuEJB"
    transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <non-jta-data-source>jdbc/MySQLConnectionPool</non-jta-data-source>
    <class>com.mesutemre.businesModel.Kitaplar</class>
    <class>com.mesutemre.businesModel.Uyeler</class>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
        <property name="eclipselink.logging.level" value="FINEST" />
        <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3307/kutuphane" />
        <property name="javax.persistence.jdbc.user" value="root" />
        <property name="javax.persistence.jdbc.password" value="root" />
        <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
    </properties>
</persistence-unit>

堆栈跟踪;

WARNING: EJB5184:A system exception occurred during an invocation on EJB UyelerDAO, method: public com.mesutemre.businesModel.Uyeler com.mesutemre.businesDAOs.UyelerDAO.findMemberByUserName(java.lang.String)

警告：javax.ejb.TransactionRolledbackLocalException：从com.sun.ejb.containers.BaseContainer.checkExceptionClientTx（BaseContainer.java:5071）中的bean抛出异常，位于com.sun.ejb.containers.BaseContainer.postInvokeTx（BaseContainer.java）：4906）com.sun.ejb.containers.BaseContainer.postInvoke（BaseContainer.java:2045）at com.sun.ejb.containers.BaseContainer.postInvoke（BaseContainer.java:1994）at com.sun.ejb.containers。 EJBLocalObjectInvocationHandler.invoke（EJBLocalObjectInvocationHandler.java:222）at at 严重：由以下原因引起：javax.ejb.TransactionRolledbackLocalException：从bean抛出的异常严重：在com.sun.ejb.containers.BaseContainer.checkExceptionClientTx（BaseContainer.java:5071）严重：在com.sun.ejb.containers.BaseContainer.postInvokeTx（BaseContainer.java:4906）严重：在com.sun.ejb.containers.BaseContainer.postInvoke（BaseContainer.java:2045）严重：......还有71个严重：由以下原因引起：java.lang.IllegalArgumentException：未知的实体bean类：类com.mesutemre.businesModel.Uyeler，请验证此类是否已使用@Entity注释进行标记。严重：在org.eclipse.persistence.internal.jpa.EntityManagerImpl.find（EntityManagerImpl.java:648）严重：

Answer 1

看起来这是GlassFish的重新部署/缓存问题。如果您使用事务类型RESOURCE_LOCAL并手动创建EntityManager并重新部署，则可能是旧的EntityManager或相应的工厂仍然由GlassFish缓存，因此只知道一些旧的值。

最快的解决方案应该是重启GlassFish并重新部署应用程序。

另一个解决方案是在un / redeployment上显式关闭EntityManagerFactory。

无论如何，首选解决方案是使用事务类型JTA，以便EntityManager由容器管理。这样更容易使用且不易出错。这是一个简短的例子：

import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

@Stateless
public class FileDAO {

    @PersistenceContext
    private EntityManager em;

    public void store(File file) {
        em.persist(file);
    }
}

另见：

带有EJB的javax.ejb.EJBTransactionRolledbackException glassfish 3.1

1 个答案: