分享程序员开发的那些事...
更新时间：2023-02-13 21:52:43
解析异常始终是一个坏主意。特别是你在这里做什么，因为你认为任何SQL异常都是违反约束的结果，实际上SQLException可能有很多许多事情。
如果你设置了数据库对字段的唯一约束，然后尝试输入两次，这就是你将得到的，明显的解决方案不是在发生错误时尝试捕获错误，而是在插入它之前手动检查它是否存在于数据库中。 / p>
Yet again it was supposed to be simple.... I was tasked with placing a certain field in the domain-objects of our application with a unique constraint. That in itself wasn't much of a challenge. I just did the following:
public class Location {
// more fields
@Column(unique = true)
@NotNull
private String locationName;
// getters and setters
}
So far so good, all went well and I got an error on running some tests against the database. Now I went ahead and started to implement Controller code, that was supposed to handle edits of the domain object.
And then all hell broke loose, because what I got back from my hibernate was some stack-trace that simply seems to prevent any sane handling of this:
18:30:20,173 ERROR [org.jboss.ejb3.invocation] (http-localhost-127.0.0.1-8443-2) JBAS014134: EJB Invocation failed on component LocationService for method public abstract long company.project.services.IService.update(java.lang.Object) throws novatec.crm.DataLayerLockException: javax.ejb.EJBTransactionRolledbackException: Transaction rolled back
at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleEndTransactionException(CMTTxInterceptor.java:115) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.as.ejb3.tx.CMTTxInterceptor.endTransaction(CMTTxInterceptor.java:95) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:232) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:304) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:190) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.6.0_45]
... 125 more
Caused by: javax.transaction.RollbackException: ARJUNA016053: Could not commit transaction.
at com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionImple.commitAndDisassociate(TransactionImple.java:1177)
at com.arjuna.ats.internal.jta.transaction.arjunacore.BaseTransaction.commit(BaseTransaction.java:117)
at com.arjuna.ats.jbossatx.BaseTransactionManagerDelegate.commit(BaseTransactionManagerDelegate.java:75)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.endTransaction(CMTTxInterceptor.java:92) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]
... 79 more
Caused by: javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: Eindeutiger Index oder Primärschlüssel verletzt: "CONSTRAINT_INDEX_9 ON PUBLIC.LOCATION(LOCATIONNAME)"
Unique index or primary key violation: "CONSTRAINT_INDEX_9 ON PUBLIC.LOCATION(LOCATIONNAME)"; SQL statement:
update Location set housenumber=?, locationName=?, numberSuffix=?, street=?, town=?, version=?, zipcode=? where id=? and version=? [23505-161]
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1361) [hibernate-entitymanager-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1289) [hibernate-entitymanager-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1295) [hibernate-entitymanager-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.ejb.AbstractEntityManagerImpl$CallbackExceptionMapperImpl.mapManagedFlushFailure(AbstractEntityManagerImpl.java:1481) [hibernate-entitymanager-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.transaction.synchronization.internal.SynchronizationCallbackCoordinatorImpl.beforeCompletion(SynchronizationCallbackCoordinatorImpl.java:109) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.transaction.synchronization.internal.RegisteredSynchronization.beforeCompletion(RegisteredSynchronization.java:53) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at com.arjuna.ats.internal.jta.resources.arjunacore.SynchronizationImple.beforeCompletion(SynchronizationImple.java:76)
at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.beforeCompletion(TwoPhaseCoordinator.java:273)
at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.end(TwoPhaseCoordinator.java:93)
at com.arjuna.ats.arjuna.AtomicAction.commit(AtomicAction.java:164)
at com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionImple.commitAndDisassociate(TransactionImple.java:1165)
... 82 more
Caused by: org.hibernate.exception.ConstraintViolationException: Eindeutiger Index oder Primärschlüssel verletzt: "CONSTRAINT_INDEX_9 ON PUBLIC.LOCATION(LOCATIONNAME)"
Unique index or primary key violation: "CONSTRAINT_INDEX_9 ON PUBLIC.LOCATION(LOCATIONNAME)"; SQL statement:
update Location set housenumber=?, locationName=?, numberSuffix=?, street=?, town=?, version=?, zipcode=? where id=? and version=? [23505-161]
at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:128) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:47) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:129) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at com.sun.proxy.$Proxy79.executeUpdate(Unknown Source)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3010) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2908) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3237) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:113) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:272) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:264) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:187) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:326) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:52) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1081) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:315) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
at org.hibernate.engine.transaction.synchronization.internal.SynchronizationCallbackCoordinatorImpl.beforeCompletion(SynchronizationCallbackCoordinatorImpl.java:104) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
... 88 more
Caused by: org.h2.jdbc.JdbcSQLException: Eindeutiger Index oder Primärschlüssel verletzt: "CONSTRAINT_INDEX_9 ON PUBLIC.LOCATION(LOCATIONNAME)"
Unique index or primary key violation: "CONSTRAINT_INDEX_9 ON PUBLIC.LOCATION(LOCATIONNAME)"; SQL statement:
update Location set housenumber=?, locationName=?, numberSuffix=?, street=?, town=?, version=?, zipcode=? where id=? and version=? [23505-161]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:329)
at org.h2.message.DbException.get(DbException.java:169)
at org.h2.message.DbException.get(DbException.java:146)
at org.h2.index.BaseIndex.getDuplicateKeyException(BaseIndex.java:81)
at org.h2.index.PageBtree.find(PageBtree.java:121)
at org.h2.index.PageBtreeLeaf.addRow(PageBtreeLeaf.java:146)
at org.h2.index.PageBtreeLeaf.addRowTry(PageBtreeLeaf.java:100)
at org.h2.index.PageBtreeIndex.addRow(PageBtreeIndex.java:105)
at org.h2.index.PageBtreeIndex.add(PageBtreeIndex.java:96)
at org.h2.table.RegularTable.addRow(RegularTable.java:121)
at org.h2.table.Table.updateRows(Table.java:439)
at org.h2.command.dml.Update.update(Update.java:128)
at org.h2.command.CommandContainer.update(CommandContainer.java:73)
at org.h2.command.Command.executeUpdate(Command.java:219)
at org.h2.server.TcpServerThread.process(TcpServerThread.java:302)
at org.h2.server.TcpServerThread.run(TcpServerThread.java:137)
at java.lang.Thread.run(Unknown Source)
at org.h2.engine.SessionRemote.done(SessionRemote.java:538)
at org.h2.command.CommandRemote.executeUpdate(CommandRemote.java:183)
at org.h2.jdbc.JdbcPreparedStatement.executeUpdateInternal(JdbcPreparedStatement.java:143)
at org.h2.jdbc.JdbcPreparedStatement.executeUpdate(JdbcPreparedStatement.java:129)
at org.jboss.jca.adapters.jdbc.WrappedPreparedStatement.executeUpdate(WrappedPreparedStatement.java:493)
at sun.reflect.GeneratedMethodAccessor391.invoke(Unknown Source) [:1.6.0_45]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [rt.jar:1.6.0_45]
at java.lang.reflect.Method.invoke(Method.java:597) [rt.jar:1.6.0_45]
at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:122) [hibernate-core-4.0.1.Final.jar:4.0.1.Final]
... 102 more
I don't want anything to do with that, and I want to save my poor user from such an exception which he can't ever be expected to handle when it crashes into his face. So I though: Hey I should hide this.. what I did was the following:
try {
service.update(object);
} catch (EJBTransactionRolledbackException e) {
Throwable root = e.getCause();
while (root.getCause() != null) {
root = root.getCause();
}
if (root instanceof java.sql.SQLException) {
// duplicate location-name
resources.produceFacesContext().addMessage(
"code",
new FacesMessage(FacesMessage.SEVERITY_WARN, "Fehler:",
"Der Standortname muss einmalig sein!"));
// german for: "Error:", "LocationName must be unique"
}
}
I think there must be a better way to handle this. There shouldn't be a necessity to revert to such hackish workarounds, just to find out, what exactly broke so you can inform the user of the mistake he's made.
Of course I could try to run the Domain Object against a Validator, that runs a defensive SELECT-statement. But it feels even more dirty to enforce database constraints in application logic, than traversing the Exception root-causes....
It feels like I am overlooking something terribly obvious.
P.S. If I don't catch the exception everything breaks... there is no nice handling of the ConstraintViolationException. I guess it's because there are no ConstraintViolations defined in there...
Parsing exceptions is always a bad idea. Especially what you are doing here because you assume any SQL exception to be a consequence of the constraint violation where in reality an SQLException can be many many things.
If you set a database unique constraint on a field, then try to enter it twice, this is what you will get, the obvious solution is not to try to catch the error when it occurs but to manually check if it exists in the database before inserting it.