Struts 2 Tutorial Series: A simple Hibernate application
Hibernate is a powerful, high performance object/relational persistence and query service. Hibernate lets you develop persistent classes following object-oriented idiom - including association, inheritance, polymorphism, composition, and collections. Hibernate allows you to express queries in its own portable SQL extension (HQL), as well as in native SQL, or with an object-oriented Criteria and Example API.
This applications main function is to add a record to database.
Tools and Libraries we Need
1. JDK 1.5 or above
2. Eclipse IDE
3. Hibernate Core 3.3.2.GA. Download Link.
JAR files required for this application:
4. mysql-connector-java-5.0.8-bin.jar download link.
Step 1: Database Setup.
Create a database "hibernate" on MySQL database. Create a table "student" using the following SQL.
CREATE TABLE /*!32312 IF NOT EXISTS*/ "student" ( "student_id" BIGINT(10) UNSIGNED NOT NULL AUTO_INCREMENT, "first_name" VARCHAR(50) DEFAULT NULL, "last_name" VARCHAR(50) DEFAULT NULL, "address" VARCHAR(50) DEFAULT NULL, PRIMARY KEY ("student_id") ) AUTO_INCREMENT=4 /*!40100 DEFAULT CHARSET=utf8*/; |
Step 2: Create Java Object
Student.java
package com.programcreek.hibernate; public class Student { private int studentId; private String firstName; private String lastName; private String address; public Student() { } public Student(String firstName, String lastName, String address){ this.firstName = firstName; this.lastName = lastName; this.address = address; } public int getStudentId(){ return studentId; } public void setStudentId(int studentId){ this.studentId = studentId; } 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; } public String getAddress(){ return address; } public void setAddress(String address){ this.address = address; } } |
Step 3: Create Mapping Files for Java Object
Student.hbm.xml
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="com.programcreek.hibernate.Student" table="student"> <id name="studentId" column="student_id"> <generator class="increment" /> </id> <property name="firstName" type="string" column="first_name" /> <property name="lastName" type="string" column="last_name" /> <property name="address" type="string" column="address" /> </class> </hibernate-mapping> |
Step 4: Create Hibernate configuration file
hibernate.cfg.xml
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/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/hibernate</property> <property name="connection.username">root</property> <property name="connection.password">admin</property> <!-- SQL dialect --> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <!-- Echo all executed SQL to stdout --> <property name="show_sql">true</property> <property name="current_session_context_class">thread</property> <mapping resource="com/programcreek/hibernate/Student.hbm.xml" /> </session-factory> </hibernate-configuration> |
Step 5: Create HibernateUtil Helper Class
HibernateUtil.java
package com.programcreek.hibernate.util; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; public class HibernateUtil { private static final SessionFactory sessionFactory; static { try { // Create the SessionFactory from hibernate.cfg.xml sessionFactory = new Configuration().configure().buildSessionFactory(); } catch (Throwable ex) { // Make sure you log the exception, as it might be swallowed System.err.println("Initial SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex); } } public static SessionFactory getSessionFactory() { return sessionFactory; } } |
Step 6: Create a Test Class to Insert a Record
Test.java
import org.hibernate.Session; import com.programcreek.hibernate.Student; import com.programcreek.hibernate.util.HibernateUtil; public class Test { public static void main(String[] args) { Session session = HibernateUtil.getSessionFactory().getCurrentSession(); session.beginTransaction(); Student s = new Student("firstname", "lastname", "address"); session.save(s); session.getTransaction().commit(); } } |
Finally, the file structure should like this.
After running the test class, the new record will be added to your database. Now we are done with a simplest case.
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