mybatis-spring-usage-guide.md

Back to Home

The Overview of MyBatis Spring Usage Guide

In this guide, we will discuss how to use MyBatis with Spring to build robust and scalable Java applications.

Step 1: Add dependencies

The first step is to add the necessary dependencies to your project. You will need the following dependencies:

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>{version}</version>
</dependency>

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>{version}</version>
</dependency>

Replace {version} with the desired version of MyBatis and MyBatis-Spring.

Step 2: Create a MyBatis configuration file

MyBatis uses an XML configuration file to define the mapping between Java objects and database tables. Create a file named mybatis-config.xml in your project's resources folder and add the following content:

<configuration>
    <typeAliases>
        <!-- Add your type aliases here -->
    </typeAliases>

    <mappers>
        <!-- Add your mappers here -->
    </mappers>
</configuration>

You can add your type aliases and mappers to this file later.

Step 3: Configure Spring to use MyBatis

To configure Spring to use MyBatis, you need to define a SqlSessionFactory bean. This bean is responsible for creating SqlSession instances, which in turn are used to execute database queries.

Add the following bean definition to your Spring configuration file:

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="configLocation" value="classpath:mybatis-config.xml"/>
</bean>

Replace dataSource with the name of your DataSource bean.

Step 4: Create a mapper interface

MyBatis uses interfaces to define database operations. Create an interface that corresponds to the database table you want to interact with.

For example, suppose you have a users table in your database. You can create a UserMapper interface like this:

public interface UserMapper {
    User getUserById(int id);
    List<User> getAllUsers();
    void insertUser(User user);
    void updateUser(User user);
    void deleteUser(int id);
}

Step 5: Create a mapper XML file

Create an XML file that maps the methods in your UserMapper interface to SQL queries. Suppose your users table has id, name, and email columns. You can create a file named UserMapper.xml in your project's resources folder and add the following content:

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

    <select id="getAllUsers" resultType="com.example.model.User">
        SELECT * FROM users
    </select>

    <insert id="insertUser" parameterType="com.example.model.User">
        INSERT INTO users (name, email) VALUES (#{name}, #{email})
    </insert>

    <update id="updateUser" parameterType="com.example.model.User">
        UPDATE users SET name = #{name}, email = #{email} WHERE id = #{id}
    </update>
    <update id="updateUser" parameterType="com.example.model.User">
        DELETE FROM users WHERE id = #{id}
    </update>
</mapper>

Step 6: Test mapper interfaces in your Spring components

@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;
    
    public User getUserById(int id) {
        return userMapper.findById(id);
    }

   public List<User> getAllUsers() {
        return userMapper.getAllUsers();
   }
   
   public void insertUser(User user) {
      userMapper.insertUser(user);
   }
   
   public void updateUser(User user) {
      userMapper.updateUser(user);
   }
   
   public void deleteUser(int id) {
      userMapper.deleteUser(id);
   }
}