10:07 a.m.
I have a problem reading Blob s in postgres
ERROR: invalid large-object descriptor: 0 (in the log you see the spanish translation)
I am not sure if it is to do with hibernate, postgres or seam.
What I wanted to do is download a file thats in a Blob.
I wrote a test using pure jdbc and the Blob in the database can be read correctly as long
as autocomit is set to false.
There are other pages that say the problem happens when not in a transaction
http://jira.jboss.com/jira/browse/JBPORTAL-575
http://archives.postgresql.org/pgsql-general/2004-09/msg00848.php
http://archives.postgresql.org/pgsql-interfaces/2000-10/msg00004.php
http://jdbc.postgresql.org/documentation/80/binary-data.html says
You must access Large Objects within an SQL transaction block. You can start a
transaction block by calling setAutoCommit(false).
but I am using a stateful session bean with an extended persistent context
also added em.joinTransaction(); just to make sure.
In the log it shows that it is in a JTATransaction, does that mean that there is a JDBC
Transaction to the database?
Two related questions:
Is what I am doing the best way to download a file?
Another question I have is when writing the Blob I use
Blob blob=Hibernate.createBlob(stream);
but dont know if this requires that the whole file be in memory.
If so how can I write it using an OutputStream
thanks in advance
Andy Bailey
In the entity bean i have
@Entity
@Name("document")
public class Document
{
private Blob content;
@Lob @Basic(fetch = FetchType.EAGER)
public Blob getContent()
{
return content;
}
public void setContent(Blob content)
{
this.content = content;
}
...
}
@Stateful
@Scope(SESSION)
@Name("documents")
public class DocumentsBean implements Serializable, Documents
{
@DataModel
private List documentList;
@DataModelSelection
@In(required=false)
@Out(required=false)
private Document document;
@PersistenceContext(type=EXTENDED)
private EntityManager em;
public void download()
{
//try to solve problem with blobs in postgres outside of transactions
em.joinTransaction();
FacesContext context = FacesContext.getCurrentInstance();
HttpServletResponse response =
( HttpServletResponse ) context.getExternalContext().getResponse();
String fileName=document.getFileName();
String contentType=document.getContentType();
int read = 0;
byte[] bytes = new byte[1024];
response.setContentType(contentType);
response.setHeader("Content-Disposition",
"attachment;filename=\"" +
fileName + "\"");
InputStream is = null;
OutputStream os = null;
try {
Blob blob=document.getContent();
is = blob.getBinaryStream();
os = response.getOutputStream();
while((read = is.read(bytes)) != -1){
os.write(bytes,0,read);
}
os.flush();
os.close();
}
catch (Exception e)
{
logger.error("download "+document,e);
}
FacesContext.getCurrentInstance().responseComplete();
}
Excerpt from the logs
2006-09-15 09:04:17,730 DEBUG [org.jboss.seam.contexts.Contexts] found in session context:
documents
2006-09-15 09:04:17,730 DEBUG [org.jboss.seam.jsf.SeamVariableResolver] resolved name to
seam component
2006-09-15 09:04:17,730 DEBUG
[org.jboss.ejb3.entity.ExtendedPersistenceContextPropagationInterceptor] ++++
LongLivedSessionPropagationInterceptor
2006-09-15 09:04:17,730 DEBUG [org.hibernate.jdbc.JDBCContext] TransactionFactory reported
no active transaction; Synchronization not
registered
2006-09-15 09:04:17,730 DEBUG [org.hibernate.ejb.AbstractEntityManagerImpl] Looking for a
JTA transaction to join
2006-09-15 09:04:17,730 DEBUG [org.hibernate.jdbc.JDBCContext] successfully registered
Synchronization
2006-09-15 09:04:17,731 DEBUG [org.jboss.seam.contexts.Contexts] found in event context:
document
2006-09-15 09:04:17,731 DEBUG [org.jboss.seam.Component] selected row: c cldc_mvm.pdf
130907 application/pdf
2006-09-15 09:04:17,731 DEBUG [org.hibernate.ejb.AbstractEntityManagerImpl] Looking for a
JTA transaction to join
2006-09-15 09:04:17,731 DEBUG [org.hibernate.ejb.AbstractEntityManagerImpl] Transaction
already joined
2006-09-15 09:04:17,800 DEBUG [org.jboss.seam.Component] instantiating Seam component:
interpolator
2006-09-15 09:04:17,800 ERROR [com.hazlorealidad.sgi.control.DocumentsBean] download c
cldc_mvm.pdf 130907 application/pdf
java.io.IOException: java.sql.SQLException: ERROR: el descriptor de objeto grande no es
válido: 0
at org.postgresql.largeobject.BlobInputStream.read(BlobInputStream.java:97)
at java.io.InputStream.read(InputStream.java:164)
at java.io.InputStream.read(InputStream.java:89)
at com.hazlorealidad.sgi.control.DocumentsBean.download(DocumentsBean.java:139)
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:585)
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:112)
at
org.jboss.ejb3.interceptor.InvocationContextImpl.proceed(InvocationContextImpl.java:166)
at
org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
at
org.jboss.seam.interceptors.ValidationInterceptor.validateTargetComponent(ValidationInterceptor.java:64)
at sun.reflect.GeneratedMethodAccessor444.invoke(Unknown Source)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
at org.jboss.seam.interceptors.Interceptor.aroundInvoke(Interceptor.java:90)
at
org.jboss.seam.interceptors.SeamInvocationContext.proceed(SeamInvocationContext.java:60)
at
org.jboss.seam.interceptors.OutcomeInterceptor.interceptOutcome(OutcomeInterceptor.java:21)
at sun.reflect.GeneratedMethodAccessor443.invoke(Unknown Source)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.seam.util.Reflections.invoke(Reflections.java:13)
...
] JNDI InitialContext
properties:{java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory,
java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces}
2006-09-15 09:04:17,910 DEBUG
[org.jboss.seam.jsf.SeamExtendedManagedPersistencePhaseListener] committing transaction
after phase: INVOKE_APPLICATION(5)
2006-09-15 09:04:17,910 DEBUG [org.jboss.seam.util.Naming] JNDI InitialContext
properties:{java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory,
java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces}
2006-09-15 09:04:17,910 DEBUG [org.hibernate.event.def.AbstractFlushingEventListener]
processing flush-time cascades
2006-09-15 09:04:17,910 DEBUG [org.hibernate.event.def.AbstractFlushingEventListener]
dirty checking collections
2006-09-15 09:04:17,910 DEBUG [org.hibernate.event.def.AbstractFlushingEventListener]
Flushed: 0 insertions, 0 updates, 0 deletions to 1 objects
2006-09-15 09:04:17,910 DEBUG [org.hibernate.event.def.AbstractFlushingEventListener]
Flushed: 0 (re)creations, 0 updates, 0 removals
to 0 collections
2006-09-15 09:04:17,910 DEBUG [org.hibernate.pretty.Printer] listing entities:
2006-09-15 09:04:17,911 DEBUG [org.hibernate.pretty.Printer]
com.hazlorealidad.sgi.model.Document{digital=false, dateRegistered=2006-09-15 09:03:53,
length=130907, content=org.hibernate.lob.SerializableBlob@e21cfc, controlled=true,
contentType=application/pdf, external=false, id=23, version=1.0, fileName=cldc_mvm.pdf,
dateModified=null, state=null, url=null, name=c}
2006-09-15 09:04:17,911 DEBUG [org.hibernate.jdbc.ConnectionManager] aggressively
releasing JDBC connection
2006-09-15 09:04:17,911 DEBUG [org.hibernate.jdbc.JDBCContext] TransactionFactory reported
no active transaction; Synchronization not..
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