MyBatis Mapper Tutorial: Step-by-Step Guide

In MyBatis, mapper interfaces are used to define methods for data operations, while the corresponding Mapper XML files are used to configure SQL statements and mapping relationships. Here are the general steps for using a mapper:

1. Create a Mapper interface: Define the methods for data operations within the interface, for example:
2. The UserMapper interface provides methods for retrieving, adding, updating, and deleting user data.
3. Create the corresponding Mapper XML file: configure SQL statements and mapping relationships in the XML file, for example:
4. The following code snippet is written in XML and defines mapping statements for CRUD operations (Create, Read, Update, Delete) for a user entity.
5. Configure the MyBatis configuration file: Configure the data source, mapper scan path and other information in the configuration file, for example:
6. The configuration includes settings for different environments, with the default set to development. The development environment uses a JDBC transaction manager and a pooled data source connected to a MySQL database. The configuration also includes a mapper for a UserMapper.xml file.
7. By utilizing the Mapper interface, one can obtain an instance of the Mapper interface through Mybatis’s SqlSessionFactory in the code, then call methods to manipulate data. For example:
   “`java
   SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
   SqlSession sqlSession = sqlSessionFactory.openSession();
   UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
   “`

Retrieve a specific user by ID, change the user’s name to “New Name”, and then update the user information using the userMapper.

Save changes and close the session.

The above is the general process of using mapper in Mybatis, hope it helps you.