Analyze MyBatis execution process: understand every aspect of data operations

MyBatis is a popular persistence framework that simplifies the interaction process with the database and provides powerful functions to help developers perform various data operations. Understanding the execution process of MyBatis is crucial to in-depth understanding of every aspect of data operations. This article will analyze the execution process of MyBatis and illustrate the implementation details of each link through specific code examples.

Section 1: Creation of SqlSessionFactory

The execution process of MyBatis begins with the creation of SqlSessionFactory. SqlSessionFactory is the core interface of MyBatis and is responsible for creating SqlSession objects. SqlSession is used to execute SQL statements and manage transactions. The following code example shows how to create a SqlSessionFactory:

String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

Section 2: Obtaining and closing SqlSession

After obtaining the SqlSessionFactory, we need to obtain the SqlSession object through it, and after the data operation is completed Then close the SqlSession. SqlSession is the session interface of MyBatis, which provides the core methods of data operations. The following is a code example for obtaining and closing SqlSession:

try (SqlSession session = sqlSessionFactory.openSession()) {
    // 执行数据库操作
}

Section 3: Mapping of Mapper interface and Mapper.xml

MyBatis implements the mapping relationship of data operations through the Mapper interface and Mapper.xml file . The Mapper interface defines data manipulation methods, and the Mapper.xml file defines the mapping relationship between SQL statements and Mapper interface methods. The following code example shows the definition of the Mapper interface and the Mapper.xml file:

Mapper interface definition:

public interface UserMapper {
    User getUserById(int id);
}

Mapper.xml file definition:

<mapper namespace="com.example.UserMapper">
    <select id="getUserById" resultType="com.example.User">
        SELECT * FROM users WHERE id = #{id}
    </select>
</mapper>

Section 4: Execution of data operations

The execution of data operations is the core part of the MyBatis execution process, which executes Mapper interface methods and SQL statements. The following is an example of data operation execution:

UserMapper userMapper = session.getMapper(UserMapper.class);
User user = userMapper.getUserById(1);

Conclusion

Through the analysis of the MyBatis execution process, we have an in-depth understanding of every aspect of data operation, including the creation of SqlSessionFactory and the acquisition of SqlSession and shutdown, mapping of Mapper interface to Mapper.xml and execution of data operations. Through specific code examples, we have a clearer understanding of the internal implementation details of MyBatis, which provides us with better guidance and reference for using MyBatis in actual projects. I hope this article can help readers better understand the execution process of MyBatis and improve the efficiency and accuracy of data operations.

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