Analysis of the technical principles of the persistent API framework in the Java class library
Analysis of the technical principles of the persistent API framework in the Java class library
Abstract: With the popularization of enterprise -level applications and the increase in data volume, the requirements for the persistence of data and the requirements of access performance are getting higher and higher.In order to solve these problems, there are some persistent API frameworks in the Java library, such as Hibernate, Mybatis, etc.This article will in -depth analysis of the technical principles of these frameworks, while providing relevant programming code and configuration examples.
1 Introduction
Persistence refers to the process of storing data to a permanent storage medium (such as disk).In traditional Java applications, data is usually stored in relational databases.However, there are some problems in the method of using the SQL statement to operate the database, such as complex object relationship mapping and performance problems.In order to solve these problems, a series of persistent API frameworks appeared.
2. Hibernate framework
Hibernate is an open source object relationship mapping (ORM) framework that can mappore the Java object and the table in the relationship database.It is mainly composed of components such as Session, SESSION FACTORIES, Transaction, Queries, and Criteria.
In Hibernate, Session is the main working unit, which is responsible for interaction with the database.Developers can perform the addition, deletion and modification operation of the database through the session object.Session Factories is used to create and manage the session object.Hibernate uses object relationship mapping technology to mappore the Java object with the table in the database, and is responsible for synchronizing the object's change to the database.
Hibernate's query language HQL (Hibernate Query Language) and Criteria query can simplify the writing process of database query and provide more advanced query functions.
Below is the example code and configuration file of Hibernate:
@Entity
@Table(name = "student")
public class Student {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(name = "name")
private String name;
// getters and setters
}
public class HibernateExample {
public static void main(String[] args) {
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
Student student = new Student();
student.setName("Alice");
session.save(student);
transaction.commit();
session.close();
sessionFactory.close();
}
}
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost/test</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">password</property>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<mapping class="com.example.Student"/>
</session-factory>
</hibernate-configuration>
3. MyBatis framework
MyBatis is another commonly used persistence API framework. It is a persistent layer framework that realizes the mapping of Java objects and SQL statements through annotations or XML files.The core components of MyBatis include SQLSessionFactory, SQLSESSION, MAPPER, and Configuration.
SQLSessionFactory is the factory class of MyBatis, responsible for creating the SQLSession object.SQLSession encapsulates all methods to interact with databases, and developers can perform CRUD operations through SQLSession.Mapper interface defines the method of database operation. Developers need to write the implementation class of the interface, or automatically generate the implementation class with the dynamic agency function provided by MyBatis.
Below is the example code and configuration file of MyBatis:
public interface StudentMapper {
@Insert("INSERT INTO student(name) VALUES (#{name})")
void insert(Student student);
}
public class MyBatisExample {
public static void main(String[] args) {
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis-config.xml"));
SqlSession session = sessionFactory.openSession();
StudentMapper mapper = session.getMapper(StudentMapper.class);
Student student = new Student();
student.setName("Alice");
mapper.insert(student);
session.commit();
session.close();
}
}
<configuration>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost/test" />
<property name="username" value="root" />
<property name="password" value="password" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper class="com.example.StudentMapper" />
</mappers>
</configuration>
4. Summary
Hibernate and Mybatis are the extensive persistence API frameworks in the Java class library.Hibernate simplifies the database operation through object relationship mapping technology, while Mybatis achieves the mapping of Java objects and SQL statements through annotations or XML files.Both provide good performance and flexible configuration. Developers can choose a framework that suits them according to specific needs.
