In -depth understanding

Hibernate is a popular ORM (object relationship mapping) framework in Java to simplify database operations and map the database table to the Java object.Hibernate Commons Annotations is a core component used in the Hibernate framework to provide annotation support, simplify configuration and enhance development efficiency.This article will explore the technical principles of the Hibernate Commons Annotation's framework and provide relevant Java code examples. 1. Framework Overview: Hibernate Commons Annotations uses annotations to make the Hibernate configuration more concise and flexible.It greatly reduces the needs of using XML configuration and provides various annotations to mappore the relationship between the Java class and the database table.Hibernate Commons Annotions is built on the top framework of Hibernate and is one of the core components in the Hibernate project. 2. Framework function: Hibernate Commons Annotions provides a series of annotations to define and configure the entity class, primary key (Primarykey), related relationships, and other mapping attributes.Below is a commonly used annotation in Hibernate Commons Annotations: -@Entity: Used to map the Java class to the database table to identify the physical class. -@Table: The name of the table in the physical class and the database is specified. -@Column: It is used to map the attributes in the Java class to the field in the database table. -@Id: Used to identify the main key field. -@GENERATEDVALUE: Used to specify the genetic strategy of the primary key, such as self -growth. -@Onetoone,@Onetomany,@Manytoone,@Manytomany: For the association relationship between physical classes. 3. Framework working principle: When using Hibernate Commons Annotations, developers can define the mapping relationship between the physical class and the database table by adding annotations to the physical class.When the application starts, Hibernate will analyze these annotations and automatically create a database table based on the definition of the annotation, or update the existing database table structure.Hibernate will also automatically mappore the Java object and database table, so that developers can directly use the Java object to operate the database. Below is a simple example, demonstrating how to use Hibernate Commons Annotations to define the physical class and mapping relationships: @Entity @Table(name = "employees") public class Employee { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @Column(name = "first_name") private String firstName; @Column(name = "last_name") private String lastName; // Getters and setters // ... } // Use hibernate in the application to perform database operations public class Main { public static void main(String[] args) { // Create a hibernate session factory SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory(); // Open a hibernate session Session session = sessionFactory.openSession(); // Open a transaction Transaction transaction = session.beginTransaction(); // Create a new employee example Employee employee = new Employee(); employee.setFirstName("John"); employee.setLastName("Doe"); // Save the employee object to the database session.save(employee); // Submit a transaction transaction.commit(); // Close the session session.close(); } } In the above example, we used the @Entity annotation to map the Employee class to the database table "Employees" and use @Column annotations to map the attribute to the field of the database table.By calling the session.save () method, we save the EMPLOYEE object created into the database. Summarize: Hibernate Commons Annotions provides a simple and powerful way to define and configure the mapping relationship between the physical class and the database table.By using annotations, developers can reduce the tedious XML configuration and intuitively understand the relationship between the physical class and the database table.The working principle of the framework is to analyze the campaign and generate or update the database table structure according to the definition of the annotation.