Hibernate：org.hibernate.AssertionFailure：com.xxx.Bean 条目中的 null id

Question

我遇到以下错误：

com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract void com.xxx.Service.save(com.xxx.Bean)' threw an unexpected exception: org.hibernate.AssertionFailure: null id in com.xxx.Bean entry (don't flush the Session after an exception occurs)
    at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:385)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:588)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
    at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:306)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:541)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:383)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:288)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:680)
Caused by: org.hibernate.AssertionFailure: null id in com.xxx.Bean entry (don't flush the Session after an exception occurs)
    at org.hibernate.event.def.DefaultFlushEntityEventListener.checkId(DefaultFlushEntityEventListener.java:82)
    at org.hibernate.event.def.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:190)
    at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:147)
    at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:219)
    at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:99)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:383)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:133)
    at com.xxx.ServiceImpl.save(ServiceImpl.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    ... 23 more

这是 MySQL 表定义：

CREATE TABLE `tblARF` (
  `ARF_ID` bigint(19) NOT NULL AUTO_INCREMENT,
  `ARF_MANUFACTURER_MNF_ID` bigint(19) NOT NULL,
  ...
  PRIMARY KEY (`ARF_ID`),
  KEY `ARF_MANUFACTURER_MNF_ID` (`ARF_MANUFACTURER_MNF_ID`)
)

这里是 Hibernate 映射：

<class name="Bean" table="tblARF">
  <id name="key" type="long" unsaved-value="null">
    <column name="ARF_ID" not-null="true"/>
    <generator class="identity" />
  </id>
<many-to-one column="ARF_MANUFACTURER_MNF_ID" name="manufacturer"
    class="ManufacturerBean" not-null="true" lazy="false"/>
...
</class>

Java 代码：

Session s = hibernate.getCurrentSession();
Transaction t = s.beginTransaction();
s.merge(bean.getManufacturer());
s.save(bean);
t.commit();

我注意到，如果我删除 KEY ARF_MANUFACTURER_MNF_ID (ARF_MANUFACTURER_MNF_ID) 而不是 AssertionFailure不会发生。有没有办法在不删除 KEY 的情况下避免此错误？

不幸的是，这个解决方案对我不起作用。

Answer 1

答案在这里找到：
https://forum.hibernate.org/viewtopic.php?f=1& ;t=1009141

'order'是SQL中的保留关键字
所以如果你想使用 if 作为一列
name 需要加引号。看
http://docs.jboss .org/hibernate/core/3.6/reference/en-US/html/mapping.html#mapping-quotedidentifiers 了解如何
启用此功能。

Answer 2

您发布的异常说明了问题是什么：

Caused by: org.hibernate.AssertionFailure: null id in com.xxx.Beanentry (don'tlush the Session after an exception indicates)

在 Hibernate 中发生与会话相关的异常后，您必须丢弃 Hibernate 会话。

但我想这不是你的问题。

你需要设置 Bean 的 ID 或使用 (@GenerateValue(strategy=GenerationType.AUTO)) 代替。

已添加
尝试将：合并替换为保存

Answer 3

我不确定这是否与您的问题有关，但请注意 merge() 的错误用法。

merge() 不会使传递给它的对象持久化，它会返回具有相同状态的另一个实例，因此您应该编写

bean.setManufacturer(s.merge(bean.getManufacturer())); 

Answer 4

有时真正的错误在于其他地方。要检查确切的错误，请使用调试模式并使用异常的 printstacktrace() 方法。它给你更详细的原因。就我而言，我使用了 String，其中列的类型为 int。