Overview
Hibernate is a Object-Replation Mapping (ORM) framework of which Java Persistent API (JPA) model is applied to the database. It maps the relationship between DB table and Java object so that it helps the persistent logic processing. In other words, when using hibernate, it is easy to access and control DB without using SQL.
Interworking with Hibernate
Downloading Hibernate
Hibernate can be downloaded at https://sourceforge.net/projects/hibernate/. When the downloaded file is decompressed, many jar files are found in lib directory. These files are used to interwork with hibernate.
Hibernate of GOLDILOCKS is created based on Hibernate version 5.2.
Interworking with GoldilocksDialect Class
GOLDILOCKS provides GoldilocksDialect.java file which is appropriate to Hibernate ORM version. When using Goldilocks.java 5 version file in Hibernate ORM 4 version, then a compile error occurs. Therefore, use GoldilocksDialect.java file which is appropriate for Hibernate version.
Especially, Hibernate ORM 4 version provides each different api according to the patch version, so GOLDILOCKS provides GoldilocksDialect.java according to it. For example, Goldilocks.java 4.0.0 version is used in Hibernate ORM 4.1.4 version, and GoldilocksDialect.java 4.1.5 version is used in Hibernate ORM 4.1.9 version.
GOLDILOCKS provides GoldilocksDialect.java in the directory under $GOLDILOCKS_HOME/app_dev/Hibernate/.
Porting to Hibernate jar File
It should be ported to the downloaded Hibernate jar file to interwork with Hibernate. GoldilocksDialect.class file and GoldilocksDialect$1.class file can be included in Hibernate jar file as follows.
Create a class file by compiling GoldilocksDialect.java file using javac. (The class file is differently created per each version.)
Decompress Hibernate jar file.
Move GoldilocksDialect.class file and GoldilocksDialect$1.class file to the decomprressed org/hibernate/dialect directory.
Compress it again with Hibernate jar file.
Add the newly created jar file to classpath.
$ javac -cp hibernate-cor-5.2.11.Final.jar GoldilocksDialect.java $ jar -xvf hibernate-core-5.2.11.Final.jar $ pwd hibernate-release-5.2.11.Final/lib/required/ $ mv GoldilocksDialect*.class org/hibernate/dialect/ $ jar -cvf hibernate.5.2.11.jar META-INF/MANIFEST.MF .
Porting to Program Source
Interworking is available by directly using the source file without porting the class file to jar file. Create org.hibernate.dialect package in the user project, then insert GoldilocksDialect.java file into this package.
Examples
Configuration
hibernate-configuration XML file and hibernate-mapping XML file are required to interqork Hibernate and DB.
Hibernate Configuration File
Configuration XML file sets the connect information to access the dialect class and DB, and sets Hibernate-mapping files. For more information, refer to Configuration.
The following is an example of hibernate.conf.xml file.
<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.connection.driver_class">sunje.goldilocks.jdbc.GoldilocksDriver</property> <property name="hibernate.connection.url">jdbc:goldilocks://192.168.0.21:22581/test</property> <property name="hibernate.connection.username">test</property> <property name="hibernate.connection.password">test</property> <property name="hibernate.dialect">org.hibernate.dialect.GoldilocksDialect</property> <property name="show_sql">true</property> <property name="format_sql">true</property> <property name="hbm2ddl.auto"> create </property> <mapping resource="SampleTable.mapping.xml" /> </session-factory> </hibernate-configuration>
Set the DB connecting information on <session-factory> tag, and specifies the dialect class name of DB to connect to hibernate.dialect property. Also, specify hibernate-mapping files by using <mapping-resource> tag.
Hibernate Mapping File
Mapping XML is a configuration file including mapping information about DB table and Java object. For more information, refer to Mapping.
The following is an example of SampleTable.mapping.xml file which was used in the example above.
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="SampleTable" table="SAMPLETABLE"> <id column="ID" name="id" type="long"> <generator class="increment" /> </id> <property column="STUDENT_NAME" name="name" type="string" /> <property column="BIGINT_VALUE" name="bigintValue" type="long" /> <property column="INT_VALUE" name="intValue" type="int" /> <property column="SMALL_VALUE" name="smallValue" type="short" /> <property column="FLOAT_VALUE" name="floatValue" type="float" /> <property column="DOUBLE_VALUE" name="doubleValue" type="double" /> <property column="NUMERIC_VALUE" name="numericValue" type="big_integer" precision="10" scale="5" /> <property column="DATE_VALUE" name="dateValue" type="date" /> <property column="TIME_VALUE" name="timeValue" type="time" /> <property column="TIMESTAMP_VALUE" name="timestampValue" type="timestamp" /> <property column="VARBINARY_VALUE" name="binaryValue" type="byte[]" /> </class> </hibernate-mapping>
The mapping information about Java class and DB table are described on <class> tag. Data type used in a table column and Java are specified on <property> tag.
Examples of Application
Java class to be mapped to DB table should be described. The following is an example of SampleTable.java which is described above.
import java.math.BigInteger;
import java.sql.Date;
import java.sql.Time;
import java.sql.Timestamp;
public class SampleTable {
private long id;
private String name;
private long bigintValue;
private int intValue;
private short smallValue;
private float floatValue;
private double doubleValue;
private BigInteger numericValue;
private Date dateValue;
private Time timeValue;
private Timestamp timestampValue;
private byte[] binaryValue;
private String longvarcharValue;
private byte[] longvarbinaryValue;
public SampleTable() {
this.name = null;
}
public SampleTable( String name ) {
this.name = name;
}
public long getId() {
return id;
}
public void setId( long id ) {
this.id = id;
}
public String getName() {
return name;
}
public void setName( String name ) {
this.name = name;
}
....get/ set function of a variable corresponding to a column of SampleTable table should be described.
The data is processed in SamleTable table as follows.
It obtains org.hibernate.SessionFactory object through a configuraion file.
It obtains org.hibernate.Session object through SessionFactory object.
It processes the desired operation by calling a method of a session object.
The following is an example of inserting, updating, retrieving, deleting data in SampleTable table of DB. It obtains SessionFactory object through org.hibernate.Configuration class.
public class HibernateSample
{
private static SessionFactory mFactory;
public static void main( String[] args ) {
try {
mFactory = new Configuration().configure( "hibernate.conf.xml" ).buildSessionFactory();
} catch( Throwable ex ) {
System.err.println( "Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
HibernateSample sHibernateSample = new HibernateSample();Insert 3 records
Long sRecord1 = sHibernateSample.addSample( "RECORD_1" ); Long sRecord2 = sHibernateSample.addSample( "RECORD_2" ); Long sRecord3 = sHibernateSample.addSample( "RECORD_3" );
Update record 1
sHibernateSample.updateSample( sRecord1, ....
Fetch table
sHibernateSample.fetchSample( 0, 3 );
Delete record 2
sHibernateSample.deleteSample( sRecord2 );
sHibernateSample.closeFactory();
}
public void closeFactory() {
mFactory.close();
}
....The following is an example of a method inserting a record to HibernateSample class. First, it obtains a session object through SessionFactory class, then obtains org.hibernate.Transaction object. It can be committed or rolled back after starting a transaction by using a transaction class and inserting a record.
public Long addSample( String name ) {
Session session = mFactory.openSession();
Transaction tx = null;
Long id = null;
try{Begin transaction
tx = (Transaction) session.beginTransaction(); SampleTable sample = new SampleTable( name );
Insert
id = (Long) session.save(sample);
Commit transaction
tx.commit();
System.out.println("add success");
} catch( HibernateException e) {
if( tx != null ) {
tx.rollback();
}
System.out.println("add fail");
e.printStackTrace();
} finally {
session.close();
}
return id;
}The following is an example of a method retrieving SampleTable table. It obtains org.hibernate.Query object through a session class. fetchSample method retrieves SampleTable from offset to count.
public void fetchSample( int offset, int count ) {
Session session = mFactory.openSession();
Query query = null;
try{
query = session.createQuery( "FROM SampleTable" );
query.setFirstResult( offset );
query.setMaxResults( count );
query.setFetchSize( 20 );
@SuppressWarnings( "unchecked" )
List<SampleTable> samples = (List<SampleTable>) query.list();
for( Iterator<SampleTable> iter = samples.iterator(); iter.hasNext(); ) {
SampleTable sample = (SampleTable) iter.next();
System.out.print( "id: " + sample.getId() );
... Ellipsis ...
}
} catch ( HibernateException e ) {
e.printStackTrace();
} finally {
session.close();
}
}The following is an exampel of a method updating SampleTable table. After altering to a set method described in SampleTable class, then it is updated by calling an update method of a session class.
public void updateSample( long id, ... ) {
Session session = mFactory.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
SampleTable sample = (SampleTable)session.get(SampleTable.class, id);
sample.setName( name );
...
session.update( sample );
tx.commit();
System.out.println( "update success" );
} catch ( HibernateException e ) {
if( tx != null ){
tx.rollback();
}
System.out.println("update fail");
e.printStackTrace();
} finally {
session.close();
}
}The following is an example of deleting a record. It can be deleted by using a delete method of a session class.
public void deleteSample( long id ) {
Session session = mFactory.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
SampleTable sample = (SampleTable) session.get( SampleTable.class, id );
session.delete( sample );
tx.commit();
System.out.println( "delete success" );
} catch ( HibernateException e ) {
if( tx != null ) {
tx.rollback();
}
System.out.println("delete fail");
e.printStackTrace();
} finally {
session.close();
}
}