Hibernate > CLOB > Oracle :(

问题:

I am trying to write to an Oracle clob field a value over 4000 characters. This seams to be a common issue but non of the solutions seem to work. So I pray for help from here.

Down and dirty info:
Using Oracle 9.2.0.8.0
Hibernate3 implementing pojo's with annotations
Tomcat 6.0.16
Oracle 10.2.x drivers
C3P0 connction pool provider

In my persistence.xml I have:

<persistence-unit name="DWEB" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <properties>
        <property name="hibernate.archive.autodetection" value="class"/> 
        <property name="hibernate.connection.password" value="###" />
        <property name="hibernate.connection.username" value="###" />
        <property name="hibernate.default_schema" value="schema" />
        <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect" />
        <property name="hibernate.c3p0.min_size" value="5" />
        <property name="hibernate.c3p0.max_size" value="20" />
        <property name="hibernate.c3p0.timeout" value="300" />
        <property name="hibernate.c3p0.max_statements" value="50" />
        <property name="hibernate.c3p0.idle_test_period" value="3000" />
        <property name="show_sql" value="true" />
        <property name="format_sql" value="true" />
        <property name="use_sql_comments" value="true" />
        <property name="SetBigStringTryClob" value="true"/>
        <property name="hibernate.jdbc.batch_size" value="0"/>
        <property name="hibernate.connection.url" value="jdbc:oracle:thin:@server.ss.com:1521:DDD"/>
        <property name="hibernate.connection.driver_class" value="oracle.jdbc.driver.OracleDriver"/>
    </properties>
</persistence-unit>

The getter and setter looks like:

@Lob 
@Column(name="COMMENT_DOC")
public String getDocument(){
    return get("Document");
}
public void setDocument(String s){
    put("Document",s);
}

The exception I am getting is:

SEVERE: Servlet.service() for servlet SW threw exception
java.sql.SQLException: Io exception: Software caused connection abort: socket write error
    at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
    at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:179)
    at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:334)
    at oracle.jdbc.ttc7.TTC7Protocol.handleIOException(TTC7Protocol.java:3678)
    at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1999)
    at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TTC7Protocol.java:1144)
    at oracle.jdbc.driver.OracleStatement.executeNonQuery(OracleStatement.java:2152)
    at oracle.jdbc.driver.OracleStatement.doExecuteOther(OracleStatement.java:2035)
    at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2876)
    at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:609)
    at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:46)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2275)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2688)
    at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:79)
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027)
    at org.hibernate.ejb.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:304)
    at org.sw.website.actions.content.AddComment.performAction(AddComment.java:60)
...

If I need to give more info pleas ask. Everything works until the dreaded limit is exceeded.

回答1:

Thanks to non sequitor for all the help. I have this working and figure I will put all the pieces here for future reference. Regardless of all the claims about upgrading the drivers and everything would work, non of that worked for me. In the end I had to implement a 'org.hibernate.usertype.UserType' I named it the same as all the examples on the web StringClobType. Save for some imports I used the example from Using Clobs/Blobs with Oracle and Hibernate. As far as I am concerned ignore the "beware" claim.

There was one change I had to make to get merges to work. Some of the methods were not implemented in the provided code sample. Eclipse fixed it for me by stubbing them out. Cool, but the replace method needs to be actually implemented or all merges will overwrite the data with a null. Here is my implementation:

public Object replace(Object newValue, Object existingValue, Object arg2)throws HibernateException {
    return newValue;
}

I will not duplicate the class implementation here go to the above link to see it. I used the code in the third gray box. Then at the top of the pojo class I wanted to use it in I added the following after the imports

...  
import org.hibernate.annotations.Type;  
import org.hibernate.annotations.TypeDefs;  
import org.hibernate.annotations.TypeDef;  

@TypeDefs({  
    @TypeDef(  
        name="clob",  
        typeClass = foo.StringClobType.class  
    )  
})  
@Entity  
@Table(name="EA_COMMENTS")  
public class Comment extends SWDataObject implements JSONString, Serializable {  
...  
}   

Then to use the new UserType I added the annotation to my getter:

@Type(type="clob")
@Column(name="COMMENT_DOC")
public String getDocument(){
    return get("Document");
}

I did not need the @Lob annotation.
In my persistence.xml the persistence-unit declaration ended looking like:

<persistence-unit name="###" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <properties>
        <property name="hibernate.archive.autodetection" value="class"/> 
        <property name="hibernate.connection.password" value="###" />
        <property name="hibernate.connection.username" value="###" />
        <property name="hibernate.connection.url" value="jdbc:oracle:thin:@server.something.com:1521:###"/>
        <property name="hibernate.connection.driver_class" value="oracle.jdbc.OracleDriver"/>
        <property name="hibernate.default_schema" value="###" />
        <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle9iDialect" />
        <property name="hibernate.c3p0.min_size" value="5" />
        <property name="hibernate.c3p0.max_size" value="100" />
        <property name="hibernate.c3p0.timeout" value="300" />
        <property name="hibernate.c3p0.max_statements" value="50" />
        <property name="hibernate.c3p0.idle_test period" value="3000" />
        <property name="hibernate.c3p0.idle_connection_test_period" value="300" />
        <property name="show_sql" value="false" />
        <property name="format_sql" value="false" />
        <property name="use_sql_comments" value="false" />
        <property name="hibernate.jdbc.batch_size" value="0"/>
    </properties>
</persistence-unit>

The SetBigStringTryClob never worked for me and was not needed for this final implementation.

My lesson learned is in the end it is probably better to join then to fight. It would of saved me three days.

回答2:

I think your problem might be that you are using Oracle 9i but Hibernate dialect is 10g. Make sure your driver,db version and dialect are all in sync because there is a 9i dialect as well org.hibernate.dialect.Oracle9iDialect

回答3:

It should be:

<property name="hibernate.connection.SetBigStringTryClob">true</property>
<property name="hibernate.jdbc.batch_size">0</property>

And not:

<property name="SetBigStringTryClob">true</property>

And use the right dialect for your database (org.hibernate.dialect.Oracle9iDialect).

Also make sure that you are using the latest Oracle 10g Release 2 thin driver (10.2.0.4) or later.

回答4:

We had a similar problem in the past, with LONG columns instead of CLOBs. The problem was the JDBC driver, the one we use now and works fine is alt text http://img143.imageshack.us/img143/4263/20091204172213.png