What is the difference between MyBatis and Hibernate?
One major difference between MyBatis and Hibernate is the way they implement ORM.
MyBatis is a lightweight persistence layer framework that supports direct writing of SQL statements, stored procedures and advanced mapping. Using MyBatis can force the use of SQL to optimize query performance, and can well control database connections to avoid blocking timeouts in connection pools.
Hibernate is a fully automatic ORM framework, the core idea is to map the object-oriented model to the relational database model. Through Hibernate, it is very convenient to manage the DAO layer uniformly, making the code of the DAO layer more concise and easy to understand.
Here is an example to illustrate the difference between the two:
// Hibernate 代码示例
// 获取当前 session 对象
Session session = sessionFactory.getCurrentSession();
// 开启一个事务
Transaction tx = session.beginTransaction();
// 使用 get() 方法查询指定 id 的 User 对象
User user = (User) session.get(User.class, userId);
// 提交事务
tx.commit();
In the above code, we first obtain the current Session object and enable transactions to operate. Then, session.get()we load Userthe object with the specified ID through the method.
Correspondingly, our implementation in MyBatis might look like this:
// MyBatis 代码示例
// 获取 SqlSession 对象
SqlSession session = sqlSessionFactory.openSession();
// 从 UserMapper 接口中获取 selectById() 方法并调用
UserMapper mapper = session.getMapper(UserMapper.class);
User user = mapper.selectById(userId);
// 关闭 SqlSession
session.close();
In this example, also get the Session object and get the selectById() method from the UserMapper interface. The difference is that Hibernate automatically maps Java objects to data tables and issues SQL statements, while MyBatis needs to manually write SQL queries.
Therefore, although Hibernate allows us to focus more on the design of entity classes and business processing logic, it also brings about problems such as ORM expansion and performance optimization; Mybatis always maintains the characteristics of a lightweight framework. Best practices for writing SQL to improve query efficiency and avoid ORMs are still strong.