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在我的ejb項目中，我定義了一個名爲DataObjectEntity.java的抽象實體類，並讓所有實體擴展這個類。其目的是使通用字段可以重複使用，並且系統中的活動記錄可以更容易。導致java.lang.NoClassDefFoundError的EJB抽象實體？
@Entity
@Inheritance(strategy= InheritanceType.TABLE_PER_CLASS)
public abstract class DataObjectEntity implements Serializable {
private static final long serialVersionUID = 1L;
@Transient
protected Logger log = Logger.getLogger(getClass());
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private PersonEntity createdBy;
@Temporal(javax.persistence.TemporalType.DATE)
private Date createdAt;
private PersonEntity lastModifiedBy;
@Temporal(javax.persistence.TemporalType.DATE)
private Date lastModifiedAt;
private boolean archived;
public DataObjectEntity() {
createdAt = new Date();
lastModifiedAt = new Date();
archived = false;
}
public DataObjectEntity(PersonEntity createdBy) {
this();
this.createdBy = createdBy;
this.lastModifiedBy = createdBy;
}
public void modified(PersonEntity modifiedBy){
this.lastModifiedBy = modifiedBy;
this.lastModifiedAt = new Date();
log.info("Object " + id + " modified by " + modifiedBy.getName());
}
public void created(PersonEntity createdBy){
this.createdBy = createdBy;
this.lastModifiedBy = createdBy;
log.info("Object " + id + " created by " + createdBy.getName());
}
//getters and setters
}
然後我用NetBeans的內置功能來生成實體類JSF頁面。一切都很好。我可以很好地運行該項目。
但是在添加一個新的實體後，我在嘗試部署時得到了這個超類實體的NoClassDefFoundError。新實體非常簡單，具有用預先存在的實體類之一定義的1-1關係。我嘗試了所有我能想到的：清潔&構建，重新啓動glassfish，刪除所有表，爲新實體類生成JSF，儘管我不需要它......但是沒有任何工作。
最終我刪除了我的新實體，只留下了現有備份bean的一些更改。錯誤仍然存在。我甚至檢出了一份新的工作副本，將相同的更改應用於後備豆 - 事實證明，副本部署良好。我的一個隊友在嘗試添加新實體時遇到了完全相同的錯誤。任何想法可能是什麼原因？
WARNING: entity/DataObjectEntity_
java.lang.NoClassDefFoundError: entity/DataObjectEntity_
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at org.glassfish.web.loader.WebappClassLoader.findClass(WebappClassLoader.java:927)
at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1486)
at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1369)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at org.eclipse.persistence.internal.helper.ConversionManager.convertObjectToClass(ConversionManager.java:438)
at org.eclipse.persistence.internal.helper.ConversionManager.convertObject(ConversionManager.java:141)
at org.eclipse.persistence.internal.databaseaccess.DatasourcePlatform.convertObject(DatasourcePlatform.java:160)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.initializeCanonicalMetamodel(EntityManagerSetupImpl.java:2552)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.getMetamodel(EntityManagerSetupImpl.java:2531)
at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:484)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:188)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:277)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:290)
at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:268)
at org.glassfish.persistence.jpa.PersistenceUnitLoader.doJava2DB(PersistenceUnitLoader.java:373)
at org.glassfish.persistence.jpa.JPADeployer$2.visitPUD(JPADeployer.java:435)
at org.glassfish.persistence.jpa.JPADeployer$PersistenceUnitDescriptorIterator.iteratePUDs(JPADeployer.java:483)
at org.glassfish.persistence.jpa.JPADeployer.iterateInitializedPUsAtApplicationPrepare(JPADeployer.java:465)
at org.glassfish.persistence.jpa.JPADeployer.event(JPADeployer.java:386)
at org.glassfish.kernel.event.EventsImpl.send(EventsImpl.java:128)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:453)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:240)
at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:382)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:355)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:370)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1064)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$1200(CommandRunnerImpl.java:96)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1244)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1232)
at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:459)
at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:209)
at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:168)
at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:117)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:238)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:680)
Caused by: java.lang.ClassNotFoundException: entity.DataObjectEntity_
at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1519)
at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1369)
... 53 more
persistence.xml文件：
<?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="MyProject-warPU" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>jdbc/myprojectdb</jta-data-source>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="eclipselink.ddl-generation" value="drop-and-create-tables"/>
</properties>
</persistence-unit>
</persistence>
更新：我的隊友發現了一個很奇怪的，但有希望的方式來解決這個問題：重命名報告的NoClassDefFoundError到的.class實體的java文件。等待glassfish編譯並報告錯誤。然後將其更改回.java。等待glassfish再次編譯，然後清理並構建，部署。每次工作。
你有任何集成測試嗎？如果是，他們通過。粘貼你的persistence.xml。我會建議創建一個測試應用程序與這個類，如果你有錯誤粘貼從測試應用程序在這裏完整的代碼。真的很難說從你發佈的內容。 – Shahzeb
我神祕地「解決」了這個問題，增加了'createdBy = null; lastModifiedBy = null;'在DataObjectEntity類的默認構造函數中。爲什麼？！ – Wei
可能與JPA2元模型類（使用「_」後綴的類）有關，並且它們需要生成。畢竟這是消息中提到的內容。爲什麼你選擇的JPA實現有一個問題，該類不存在是另一回事...... – DataNucleus