Play Store Application link – Hibernate – in 10 steps – Apps on Google Play
Configuring Hibernate is the process of setting up the framework to connect to a database, define mapping files and specify the persistent objects that will be used in the application.
There are following steps to perform-
1- Importing Hibernate libraries (Classes/Interfaces)
2- Creating Hibernate Configuration File
Step 1-
- Add Hibernate libraries to your project
- Libraries can be found on the Hibernate website
- Libraries needed: core Hibernate framework, Hibernate annotations, and database driver
Here is an example of how to add the necessary libraries to a project using Maven:
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.3.5.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-annotations</artifactId>
<version>3.5.6-Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.24</version>
</dependency>
-> Group ID (groupId): It’s like a company or organization name that groups related projects together. Example: org.hibernate means it belongs to the Hibernate organization.
->Artifact ID (artifactId): It’s the specific project or library name within that group. Example: hibernate-core means it is the core Hibernate library.
Note – There are several alternative ways to import dependencies without using a pom.xml file:
- You can manually download the JAR files for the dependencies and add them to the classpath of your project.
- You can use the Gradle or Apache Ivy build tools, which do not require a pom.xml file. Instead, you can specify dependencies in a build.gradle or ivy.xml file.
- You can use a package manager such as Maven Wrapper, SDKMAN or Jabba that can download the dependencies and manage them for you, without the need for a pom.xml file.
- You can use a build tool like Apache Ant which uses build.xml file instead of pom.xml to manage dependencies.
- Some IDEs like Eclipse and IntelliJ IDEA also have support for adding dependencies to a project without using a pom.xml file.
Important-
| Hibernate Interfaces/Class | Description |
|---|---|
| Configuration class | Used to configure Hibernate settings and create a SessionFactory |
| Session Interface | Represents a single unit of work with the database, used for creating, reading, updating, and deleting objects, and committing or rolling back a transaction |
| SessionFactory Interface | Factory for creating Session objects, thread-safe and can be used to create multiple sessions |
| Transaction Interface | Represents a unit of work with the database, used to group multiple operations together and commit or rollback all of them at once |
| Query Interface | Used to execute HQL (Hibernate Query Language) and native SQL queries, can be used to retrieve, update, or delete data |
| Criteria Interface | Used to create type-safe and type-sensitive queries, can be used to retrieve data based on certain criteria, retrieve specific fields, or retrieve data based on certain conditions |
Step 2- Next,
- Create a configuration file named “hibernate.cfg.xml” put it in resources folder
- Include connection details for the database
- Information to include: database URL, username, password, SQL dialect
Here is an example of a 1- Basic hibernate.cfg.xml configuration file:
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//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:3306/mydatabase</property>
<property name="connection.username">myusername</property>
<property name="connection.password">mypassword</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</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">create</property>
<!-- Mapping files -->
<mapping resource="com/mypackage/mypersistentobject.hbm.xml"/>
</session-factory>
</hibernate-configuration>
Detailed explanation –
| XML Part / Feature | Meaning | Real-World Example | Impact on XML File |
|---|---|---|---|
| XML Version | 1.0 (Standard) / 1.1 (Rare) | Version of a software update | 1.0 is universal; 1.1 supports rare characters. |
| Encoding | UTF-8, UTF-16, ISO-8859-1, ASCII | Choosing a keyboard language | UTF-8 supports all languages; ASCII only basic English. |
| DOCTYPE & DTD | Defines XML rules | Exam guidelines ensuring correct answers | Ensures correct structure; missing DTD means no validation. |
| DTD URL | http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd | A reference manual for exam rules | Hibernate checks this URL to verify XML correctness. |
| hibernate.connection.driver_class | Which database driver to use | Choosing a taxi service (Ola, Uber) | Determines which database (MySQL, PostgreSQL, etc.) is used. |
| hibernate.connection.url | Where the database is | Google Maps location link | Specifies the database address and name. |
| hibernate.connection.username | Database username | Your login username | Identifies the user in the database. |
| hibernate.connection.password | Database password | Your login password | Grants access to the database. |
| hibernate.dialect | SQL syntax for Hibernate | Choosing a language for communication | Ensures compatibility with different databases. |
| hibernate.show_sql | Show SQL in logs | Debug mode in a game | Helps developers see the actual queries being executed. |
| hbm2ddl.auto | How to handle tables | Erasing or updating a whiteboard | Controls table creation, updates, and deletion. |
<mapping resource> | Maps Java class to database table | A blueprint for object-to-table conversion | Defines which Java class is linked to which DB table. |
Note – There are several alternative ways to create a Hibernate configuration file, instead of using a hibernate.cfg.xml file:
2- Using a Java class: A Java class can be used to create a Hibernate configuration object, which can be used to configure Hibernate.
import org.hibernate.cfg.Configuration;
public class HibernateConfig {
public static Configuration getConfig() {
Configuration config = new Configuration();
config.setProperty("hibernate.connection.driver_class", "com.mysql.jdbc.Driver");
config.setProperty("hibernate.connection.url", "jdbc:mysql://localhost:3306/mydatabase");
config.setProperty("hibernate.connection.username", "myusername");
config.setProperty("hibernate.connection.password", "mypassword");
config.setProperty("hibernate.connection.pool_size", "1");
config.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5InnoDBDialect");
config.setProperty("hibernate.current_session_context_class", "thread");
config.setProperty("hibernate.cache.provider_class", "org.hibernate.cache.NoCacheProvider");
config.setProperty("hibernate.show_sql", "true");
config.setProperty("hibernate.hbm2ddl.auto", "create");
config.addResource("com/mypackage/mypersistentobject.hbm.xml");
return config;
}
}
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