Reverse-engineer POJOs from a database

In this post, we will see how to create POJO from the existing database (reverse engineering). 

First let us setup the development environment. Download this document and follow the step by step instruction to install the necessary software’s.

We are going to create POJO from the existing database in mysql. So let us download driver for the same. You can download the driver here

Step 1:
In the Eclipse, Select File –> New –> Other->JPA Project

Click Next


Enter the Project Name and leave all the other options as default and click Next.

Click Next

For JPA Implementation Type , select Disable Library Configuration
Next click Add connection, Select mysql


Click Next

Select New Driver Information next drivers drop down.


Select MYSQL 5.1 and goto JAR List tab. Add the Connector zip file which we downloaded earlier.

Click ok and Test your mysql connection in the following screen.


After testing the connection, you can click finish and come back to starting screen



Now you can click finish button to create the project with the connection information.



Now click on the Project Name and Right Click, Select New –> JPA Entities from the Tables



It will show all the tables in the connected database. You can choose all the tables and Click Next



You can verify all the foreign key relationship. In this example, i do not have more than one table, so it is empty. Click Next

Here you can Key Generator as Identity and you can modify/leave to default for other properties.Click Next

Click Next and Click Finish
Now You can see all the POJO classes are created with the relationship.

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Annotate non persistent properties with the @Transient Annotation

In Most of the cases, all the Java bean properties (example, firstname, lastname, email, etc.) that need to be stored to the database. But in some situation, we might have other properties that do not need to be stored in the database. In this case, we need to say to hibernate that do not take this property for all the Database operation. This can be done using @Transient annotation.

By default, all fields in your class will be persisted to the database if possible. If there is a field that should not be recorded in the database, mark that field with the @Transient annotation

Now let us do an example on the above subject

Step 1:

Create the hibernate setup as shown here;

Step 2:

Now let us modify our patient.java by adding a non persistent field

package mypack;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Column;
import javax.persistence.Transient;

@Entity
@Table(name = "patient")
public class patient {

    private Integer id;
    private String firstName;
    private String lastName;
    private String password;

    @Transient
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Id
    @GeneratedValue
    @Column(name = "ID")
    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @Column(name = "firstname")
    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    @Column(name = "lastname")
    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

Step 3:

Let us modify test.java to create new patient as follows

package mypack;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.hibernate.HibernateException;

import Utility.HibernateUtil;

public class Test {

    private static SessionFactory factory;
    private static ServiceRegistry serviceRegistry;

    public static void main(String[] args) {
        createpatient();
        getAllRecords();
    }

    public static void getAllRecords() {
        List allpatients;
        Session session = HibernateUtil.beginTransaction();
        Query q1 = session.createQuery("from patient");
        allpatients = q1.list();
        for (int i = 0; i < allpatients.size(); i++) {
            patient pt = (patient) allpatients.get(i);
            System.out.println(pt.getLastName());
        }
        HibernateUtil.CommitTransaction();
    }

    public static void createpatient() {
        
        Session session = HibernateUtil.beginTransaction();
        patient p1 = new patient();
        p1.setFirstName("Mark");
        p1.setLastName("Anderson");
        p1.setPassword("1234");
        session.save(p1);
        HibernateUtil.CommitTransaction();
    }

}

Step 4:

Run the test.java as Java Application and the following is the output

Hibernate: insert into patient (firstname, lastname) values (?, ?)
Hibernate: select patient0_.ID as ID0_, patient0_.firstname as firstname0_, patient0_.lastname as lastname0_ from patient patient0_
John
DAVID
JOSEPH
Anderson

Another good example

public enum Gender { MALE, FEMALE, UNKNOWN }

@Entity
public Person {
    private Gender g;
    private long id;

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    public long getId() { return id; }
    public void setId(long id) { this.id = id; }

    public Gender getGender() { return g; }    
    public void setGender(Gender g) { this.g = g; }

    @Transient
    public boolean isMale() {
        return Gender.MALE.equals(g);
    }

    @Transient
    public boolean isFemale() {
        return Gender.FEMALE.equals(g);
    }
}

Read More

Hibernate Introduction Part 4

 

This article is a continuation of our previous article.

In the previous post, we have seen how to retrieve all the records in the database. But most of time, this is not the case.  Sometime we need to retrieve particular record by passing the primary key.

Say for example, in SQL

Select * from User where UserID=’John’

This can be achieved in HQL using Variable injection option

And also , When we expect multiple rows, then we know what we can use Query’s List method() as we seen in the previous example. On the other hand, When we expect a single record, then we can use Query’s  uniqueResult()

 

Here is the full code for the Method to retrieve the unique record

 

public static void getPatientByID(int anyvalue) {

    try {
        Configuration configuration = new Configuration();
        configuration.configure();
        serviceRegistry = new ServiceRegistryBuilder().applySettings(
                configuration.getProperties()).buildServiceRegistry();
        factory = configuration.buildSessionFactory(serviceRegistry);
    } catch (Throwable ex) {
        System.err.println("Failed to create sessionFactory object." + ex);
        throw new ExceptionInInitializerError(ex);
    }
    System.out.println("**Example : Hibernate  SessionFactory**");
    System.out.println("----------------------------------------");
   
    Session session = factory.openSession();
    Transaction tx = null;
    try {
        tx = session.beginTransaction();
        Query q1 = session.createQuery("from patient where id =:idvalue");
        q1.setInteger("idvalue", anyvalue);
        Object queryResult = q1.uniqueResult();
        patient p1 = (patient)queryResult;
        tx.commit();
        System.out.print(p1.getLastName());
    } catch (HibernateException e) {
        if (tx != null)
            tx.rollback();
        e.printStackTrace();
    } finally {
        session.close();
    }
}

 

Here is the updated test.java code

package mypack;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.hibernate.HibernateException;

public class Test {

    private static SessionFactory factory;
    private static ServiceRegistry serviceRegistry;

    public static void main(String[] args) {
        createRecords();
        getAllRecords();
        getPatientByID(1);
        getPatientByID(13);
       
    }

    public static void createRecords() {

        try {
            Configuration configuration = new Configuration();
            configuration.configure();
            serviceRegistry = new ServiceRegistryBuilder().applySettings(
                    configuration.getProperties()).buildServiceRegistry();
            factory = configuration.buildSessionFactory(serviceRegistry);
        } catch (Throwable ex) {
            System.err.println("Failed to create sessionFactory object." + ex);
            throw new ExceptionInInitializerError(ex);
        }
        System.out.println("**Example : Hibernate 4 SessionFactory**");
        System.out.println("----------------------------------------");

        Session session = factory.openSession();
        Transaction tx = null;
        try {
            tx = session.beginTransaction();
            patient pt = new patient();
            pt.setFirstName("John12");
            pt.setLastName("Smith23");
            session.saveOrUpdate(pt);
            tx.commit();
        } catch (HibernateException e) {
            if (tx != null)
                tx.rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }
    }
   
    public static void getAllRecords() {

        try {
            Configuration configuration = new Configuration();
            configuration.configure();
            serviceRegistry = new ServiceRegistryBuilder().applySettings(
                    configuration.getProperties()).buildServiceRegistry();
            factory = configuration.buildSessionFactory(serviceRegistry);
        } catch (Throwable ex) {
            System.err.println("Failed to create sessionFactory object." + ex);
            throw new ExceptionInInitializerError(ex);
        }
        System.out.println("**Example : Hibernate  SessionFactory**");
        System.out.println("----------------------------------------");
       
        List allpatients;
       
        Session session = factory.openSession();
        Transaction tx = null;
        try {
            tx = session.beginTransaction();
            Query q1 = session.createQuery("from patient");
            allpatients = q1.list();
            for (int i =0; i < allpatients.size(); i++)
            {
                patient pt = (patient) allpatients.get(i);
                System.out.println(pt.getLastName());
            }
            tx.commit();
        } catch (HibernateException e) {
            if (tx != null)
                tx.rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }
    }

   
    public static void getPatientByID(int anyvalue) {

        try {
            Configuration configuration = new Configuration();
            configuration.configure();
            serviceRegistry = new ServiceRegistryBuilder().applySettings(
                    configuration.getProperties()).buildServiceRegistry();
            factory = configuration.buildSessionFactory(serviceRegistry);
        } catch (Throwable ex) {
            System.err.println("Failed to create sessionFactory object." + ex);
            throw new ExceptionInInitializerError(ex);
        }
        System.out.println("**Example : Hibernate  SessionFactory**");
        System.out.println("----------------------------------------");
       
       
       
        Session session = factory.openSession();
        Transaction tx = null;
        try {
            tx = session.beginTransaction();
            Query q1 = session.createQuery("from patient where id =:idvalue");
            q1.setInteger("idvalue", anyvalue);
            Object queryResult = q1.uniqueResult();
            patient p1 = (patient)queryResult;
            tx.commit();
            System.out.print(p1.getLastName());
        } catch (HibernateException e) {
            if (tx != null)
                tx.rollback();
            e.printStackTrace();
        } finally {
            session.close();
        }
    }

}

Read More

Hibernate Introduction Part 3

Data query.

Well, Now we will see how to query all the records inserted into the database that we have done
in part 1 and part 2.

For all the future examples (including this), i am going use only JPA Annotations

let's start.

Step 1: Development environment

1. My sql server 5.0  Download
2. Hibernate 4.1.1 Download
3. JDBC Driver for Mysql ((mysql-connector-java-5.1.19.zip)) Download
4. Eclipse IDE

Unzip the hibernate buddle and you should have the following structure after you unzip
Documentation folder
lib Folder
Project folder
log text file
hibernate logo image
license text file


Step 2:

Open mysql and create the following table in any of the exisitng database or create new database.
Here is the script for our table


CREATE TABLE `patient`
 (
    `ID` INT(11) NOT NULL AUTO_INCREMENT,
    `FirstName` VARCHAR(100) DEFAULT NULL,
    `LastName` VARCHAR(100) DEFAULT NULL,
    `Email` VARCHAR(200) DEFAULT NULL,
     PRIMARY KEY  (`ID`)
 )  ENGINE=INNODB DEFAULT


Step 3: Eclipse Java project

1. Click File -> New -> Other -> Java Project

2. Say Example3 for Project Name and leave all other to default values.
   (Make sure, JRE has been configured).

3. Next we will add all dependencies in the example3. Now click Example3 project in the project
   explorer and right click -> Click New-> Folder. Say folder name as lib

   Now copy the following files into lib folder
   (Note : Eclipse project explorer accepts all copy and paste operation. For example, you can copy    

   file or folder in windows explorer and then you can come back to eclipse project explorer and paste

  it)

   All the files in Hibernate->Lib->required.
   All the files in Hibernate->Lib->jpa.
   All the files in Hibernate->Lib->envers
   mysql-connector-java-5.1.18-bin.jar


4. Now  setup the build path. In order to execute our example, all the above jar files should be in
   class build path

   Again, click on the Example1, right click, and select build Path->configure build path.
   Go to Libraries-> External jars,  browse lib folder you created earlier. Then add external jars by
   selecting all jar files that you copied to lib folder in one of previous step


Step 4: Creating Java beans

Now let us create the java bean for the patient where we want to store in the database.

Again, right click on Example1, Select New -> Class; Package Name : mypack and Class name

:patient Leave the all other to default values

Now type or copy the following


package mypack;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Column;

@Entity
@Table(name="patient")
public class patient {

private Integer id;
private String firstName;
private String lastName;

@Id
@GeneratedValue
@Column(name="ID")
public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

@Column(name="firstname")
public String getFirstName() {
return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

@Column(name="lastname")
public String getLastName() {
return lastName;
}

public void setLastName(String lastName) {
this.lastName = lastName;
}

}



Step 6 : Hibernate Configuration

Now we have the persistent class and its mapping information using Annotations in place.
Let’s configure Hibernate.



Right Click src->New->File. File Name as hibernate.hbm.xml
Paste following code there. Save it as hibernate.cfg.xml. Here you have to give the

username,password and database name according to your MySQL account.


<?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>
 <!-- Database connection settings -->
 <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
 <property name="connection.url">jdbc:mysql://localhost/sampledb</property>
 <property name="connection.username">root</property>
 <property name="connection.password">123</property>

 <!-- JDBC connection pool (use the built-in) -->
 <property name="connection.pool_size">1</property>

 <!-- SQL dialect -->
 <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

  <!-- Enable Hibernate's automatic session context management -->
  <property name="current_session_context_class">thread</property>

  <!-- Disable the second-level cache -->
  <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

  <!-- Echo all executed SQL to stdout -->
  <property name="show_sql">true</property>

  <!-- Drop and re-create the database schema on startup -->
  <property name="hbm2ddl.auto">update</property>

  <!-- Mapping files -->
  <mapping resource="patient.hbm.xml" />

  </session-factory>
</hibernate-configuration>


Step 7: Create Test class to store the objects

To create new class right click on "mypack" package and select New --> Class and give Name as

Test.java and paste the following code in class file.



package mypack;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.hibernate.HibernateException;

public class Test {

private static SessionFactory factory;
private static ServiceRegistry serviceRegistry;

public static void main(String[] args) {
createRecords();

}

public static void createRecords() {

try {
Configuration configuration = new Configuration();
configuration.configure();
serviceRegistry = new ServiceRegistryBuilder().applySettings(
configuration.getProperties()).buildServiceRegistry();
factory = configuration.buildSessionFactory(serviceRegistry);
} catch (Throwable ex) {
System.err.println("Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
System.out.println("**Example : Hibernate 4 SessionFactory**");
System.out.println("----------------------------------------");

Session session = factory.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
patient pt = new patient();
pt.setFirstName("John124");
pt.setLastName("Smith234");
session.saveOrUpdate(pt);
tx.commit();
} catch (HibernateException e) {
if (tx != null)
tx.rollback();
e.printStackTrace();
} finally {
session.close();
}
}

}


Now right click on test.java file and select Run as -> Java Application
If every thing configured correctly, then you will the see the following lines in the console at the
end

INFO: HHH000126: Indexes: [primary]
Apr 29, 2012 10:14:49 PM org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000232: Schema update complete
**Example : Hibernate 4 SessionFactory**
----------------------------------------
Hibernate: insert into PATIENT (FIRSTNAME, LASTNAME) values (?, ?)

Now go to database and check records are inserted into patient table.

Run again and again to insert more records by changing the last name and first name.
So that in the next step, we can see how we can retrieve the records.


Step 7: Get records and display in the console.

Small Intro on Hibernate Query Language

Hibernate uses a powerful query language (HQL) that is similar in appearance to SQL. Compared with SQL,

however, HQL is fully object-oriented and understands notions like inheritance, polymorphism and

association. Since it is an object-oriented equivalent of SQL, all of the functions of retrieval are

provided out-of-the-box in HQL. These functions can be classified into four categories:

1. Projection

2. Restriction

3. Aggregation

4. Grouping


Examples for Projection
"from patient"

The above will returns all of the instances of the patient.
This is equivalent to the following SQL : SELECT * FROM patient

Examples for Restriction
SELECT * FROM patient WHERE lastname='John';

Coming back to our example, let us get all the patients from the database and print the last name
in the console.

Modified Test.Java as follows

package mypack;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.hibernate.HibernateException;

public class Test {

private static SessionFactory factory;
private static ServiceRegistry serviceRegistry;

public static void main(String[] args) {
createRecords();
getAllRecords();

}

public static void createRecords() {

try {
Configuration configuration = new Configuration();
configuration.configure();
serviceRegistry = new ServiceRegistryBuilder().applySettings(
configuration.getProperties()).buildServiceRegistry();
factory = configuration.buildSessionFactory(serviceRegistry);
} catch (Throwable ex) {
System.err.println("Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
System.out.println("**Example : Hibernate 4 SessionFactory**");
System.out.println("----------------------------------------");

Session session = factory.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
patient pt = new patient();
pt.setFirstName("John12");
pt.setLastName("Smith23");
session.saveOrUpdate(pt);
tx.commit();
} catch (HibernateException e) {
if (tx != null)
tx.rollback();
e.printStackTrace();
} finally {
session.close();
}
}

public static void getAllRecords() {

try {
Configuration configuration = new Configuration();
configuration.configure();
serviceRegistry = new ServiceRegistryBuilder().applySettings(
configuration.getProperties()).buildServiceRegistry();
factory = configuration.buildSessionFactory(serviceRegistry);
} catch (Throwable ex) {
System.err.println("Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
System.out.println("**Example : Hibernate  SessionFactory**");
System.out.println("----------------------------------------");

List allpatients;

Session session = factory.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
Query q1 = session.createQuery("from patient");
allpatients = q1.list();
for (int i =0; i < allpatients.size(); i++)
{
patient pt = (patient) allpatients.get(i);
System.out.println(pt.getLastName());
}
tx.commit();
} catch (HibernateException e) {
if (tx != null)
tx.rollback();
e.printStackTrace();
} finally {
session.close();
}
}

}


Now right click on test.java file and select Run as -> Java Application. Last name will be
printed in the console.

Read More

Hibernate Introduction Part 2

Hibernate Annotations
This example is the same as the first example except that it uses annotations. There we first started
by creating the .hbm.xml file, here there is no need to create it instead we will use annotations to do
the object relational mapping.

Step 1 : Remove the patient.hbm.xml file

Step 2 ; Open the hibernate.cfg.xml and replace the following line

<!-- Mapping files -->
<mapping resource="patient.hbm.xml" />

With


<!-- Mapping Classes -->
<mapping class="mypack.patient" />


Step 3 : Open the patient.java and replace as follows


package mypack;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Column;



@Entity
@Table(name="patient")
public class patient {

private Integer id;
private String firstName;
private String lastName;

@Id
@GeneratedValue
@Column(name="ID")
public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

@Column(name="firstname")
public String getFirstName() {
return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

@Column(name="lastname")
public String getLastName() {
return lastName;
}

public void setLastName(String lastName) {
this.lastName = lastName;
}

}

Step 4:  No Change in Test.java . Just right click as Test.java and run as Java application.

Read More

Hibernate Introduction Part 1

So What is hibernate ?
Here is the answer
Click the following link
Link

:) Well, if you have time, just go thru each and understand. Otherwise, simply put, using hibernate
it is each save the data into the database or load the data from the database.

Well, let's start.

Step 1: Development environment

1. My sql server 5.0  Download
2. Hibernate 4.1.1 Download
3. JDBC Driver for Mysql ((mysql-connector-java-5.1.19.zip)) Download
4. Eclipse IDE

Unzip the hibernate buddle and you should have the following structure after you unzip
Documentation folder
lib Folder
Project folder
log text file
hibernate logo image
license text file


Step 2:

Open mysql and create the following table in any of the exisitng database or create new database.
Here is the script for our table


CREATE TABLE `patient`
(
           `ID` INT(11) NOT NULL AUTO_INCREMENT,
  `FirstName` VARCHAR(100) DEFAULT NULL,
    `LastName` VARCHAR(100) DEFAULT NULL,
           `Email` VARCHAR(200) DEFAULT NULL,
           PRIMARY KEY  (`ID`)
       ) ENGINE=INNODB DEFAULT


Step 3: Eclipse Java project

1. Click File -> New -> Other -> Java Project
2. Say Example1 for Project Name and leave all other to default values.
   (Make sure, JRE has been configured).
3. Next we will add all dependencies in the example1. Now click Example1 project in the project
   explorer and right click -> Click New-> Folder. Say folder name as lib

   Now copy the following files into lib folder
   (Eclipse project explorer accepts all copy and paste operation. For example, you can copy file
    or folder in windows explorer and then you can come back to eclipse project explorer and paste it)

     All the files in Hibernate->Lib->required.
     All the files in Hibernate->Lib->jpa.
     All the files in Hibernate->Lib->envers
     mysql-connector-java-5.1.18-bin.jar

4. Now  setup the build path. In order to execute our example, all the above jar files should be in
class build path

   Again, click on the Example1, right click, and select build Path->configure build path.
   Go to Libraries-> External jars,  browse lib folder you created earlier. Then add external jars by

 selecting all jar files that you copied to lib folder in one of previous step

Step 4: Creating Java beans

Now let us create the java bean for the patient where we want to store in the database.

Again, right click on Example1, Select New -> Class; Package Name : mypack and Class name :patient
Leave the all other to default values

Now type or copy the following

package mypack;

public class patient {

private Integer id;
private String firstName;
private String lastName;

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getFirstName() {
return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

public String getLastName() {
return lastName;
}

public void setLastName(String lastName) {
this.lastName = lastName;
}

}


Step 5: Mapping between Java bean and Table.

Let us first summarize what we have done so far. 1) My sql table 2) Java bean.

Now, important step, we will see how to map 1) and 2) , so that whenever new object is created,
it will insert one record in the database.


Hibernate makes persisting the state of your Java objects incredibly simple. However, in order for

Hibernate to know where to story your JavaBeans, or how to map the property of a JavaBean to a database

column, the developer has to provide a bit of direction to the Hibernate framework.

This is where the Hibernate mapping file comes into play. The mapping file tells Hibernate what table

in the database it has to access, and what columns in that table it should use.


Using JPA annotations also, we can do the same. In this example, first we will see using mapping files
and then we will convert the same example to JPA annotations.


Now let us create the mapping file
Right Click src->New->File. File Name as patient.hbm.xml

Type or copy the below content


<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Apr 29, 2012 6:48:24 PM by Hibernate Tools 3.4.0.CR1 -->
<hibernate-mapping>
    <class name="mypack.patient" table="PATIENT">
        <id name="id" type="java.lang.Integer">
            <column name="ID" />
            <generator class="native" />
        </id>
        <property name="firstName" type="java.lang.String">
            <column name="FIRSTNAME" />
        </property>
        <property name="lastName" type="java.lang.String">
            <column name="LASTNAME" />
        </property>
    </class>
</hibernate-mapping>


Step 6 : Hibernate Configuration

Now we have the persistent class and its mapping file in place. Let’s configure Hibernate.

Right Click src->New->File. File Name as hibernate.hbm.xml

Paste following code there. Save it as hibernate.cfg.xml. Here you have to give the username,password

and database name according to your MySQL account.


<?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>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost/sampledb</property>
<property name="connection.username">root</property>
<property name="connection.password">123</property>

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>

<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">update</property>

<!-- Mapping files -->
<mapping resource="patient.hbm.xml" />

</session-factory>
</hibernate-configuration>


Step 7: Create Test class to store the objects

To create new class right click on "mypack" package and select New --> Class and give Name as Test.java

and paste the following code in class file.


package mypack;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
import org.hibernate.HibernateException;

public class Test {

private static SessionFactory factory;
private static ServiceRegistry serviceRegistry;

public static void main(String[] args) {
try {
Configuration configuration = new Configuration();
configuration.configure();
serviceRegistry = new ServiceRegistryBuilder().applySettings(
configuration.getProperties()).buildServiceRegistry();
factory = configuration.buildSessionFactory(serviceRegistry);
} catch (Throwable ex) {
System.err.println("Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
System.out.println("**Example : Hibernate 4 SessionFactory**");
System.out.println("----------------------------------------");

Session session = factory.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();
patient pt = new patient();
pt.setFirstName("John");
pt.setLastName("Smith");
session.saveOrUpdate(pt);
tx.commit();
} catch (HibernateException e) {
if (tx != null)
tx.rollback();
e.printStackTrace();
} finally {
session.close();
}
}
}


Now right click on test.java file and select Run as -> Java Application
If every thing configured correctly, then you will the see the following lines in the console at the
end

INFO: HHH000126: Indexes: [primary]
Apr 29, 2012 10:14:49 PM org.hibernate.tool.hbm2ddl.SchemaUpdate execute
INFO: HHH000232: Schema update complete
**Example : Hibernate 4 SessionFactory**
----------------------------------------
Hibernate: insert into PATIENT (FIRSTNAME, LASTNAME) values (?, ?)

Now go to database and check records are inserted into patient table.

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