How to Integrate MyBatis with Spring Boot for CRUD Operations

Previously we introduced two ways to access relational databases in Spring Boot: spring-boot-starter-jdbc and spring-boot-starter-data-jpa. This article demonstrates how to integrate MyBatis to perform CRUD operations.

Integrating MyBatis

Step 1: Add MyBatis starter and MySQL connector dependencies to pom.xml:

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.1</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

Version 2.1.x supports MyBatis 3.5+, Java 8+, Spring Boot 2.1+. Versions 2.0.x and 1.3.x support older Spring Boot releases.

Step 2: Configure MySQL connection in application.properties:

spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

You may also use Druid as the connection pool if desired.

Step 3: Create a test table in MySQL, e.g., User with columns id (BIGINT), name (VARCHAR), and age (INT):

CREATE TABLE `User` (
  `id` bigint NOT NULL AUTO_INCREMENT,
  `name` varchar(100) COLLATE utf8mb4_general_ci DEFAULT NULL,
  `age` int DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

Step 4: Define the User entity:

@Data
@NoArgsConstructor
public class User {
    private Long id;
    private String name;
    private Integer age;
    public User(String name, Integer age) {
        this.name = name;
        this.age = age;
    }
}

Step 5: Create the mapper interface UserMapper with insert and select methods:

@Mapper
public interface UserMapper {
    @Select("SELECT * FROM USER WHERE NAME = #{name}")
    User findByName(@Param("name") String name);

    @Insert("INSERT INTO USER(NAME, AGE) VALUES(#{name}, #{age})")
    int insert(@Param("name") String name, @Param("age") Integer age);
}

Step 6: Add the Spring Boot main class:

@SpringBootApplication
public class Chapter35Application {
    public static void main(String[] args) {
        SpringApplication.run(Chapter35Application.class, args);
    }
}

Step 7: Write a unit test to verify CRUD operations:

@Slf4j
@RunWith(SpringRunner.class)
@SpringBootTest
public class Chapter35ApplicationTests {
    @Autowired
    private UserMapper userMapper;

    @Test
    @Rollback
    public void test() throws Exception {
        userMapper.insert("AAA", 20);
        User u = userMapper.findByName("AAA");
        Assert.assertEquals(20, u.getAge().intValue());
    }
}

Annotation Usage

MyBatis provides several ways to pass parameters:

@Param: Directly map method parameters to SQL placeholders.

Map: Use a Map<String, Object> where keys correspond to placeholders.

Object: Pass a POJO (e.g., User) and MyBatis binds its fields.

Typical CRUD annotations include @Select, @Insert, @Update, and @Delete. Example interface covering all four:

public interface UserMapper {
    @Select("SELECT * FROM user WHERE name = #{name}")
    User findByName(@Param("name") String name);

    @Insert("INSERT INTO user(name, age) VALUES(#{name}, #{age})")
    int insert(@Param("name") String name, @Param("age") Integer age);

    @Update("UPDATE user SET age=#{age} WHERE name=#{name}")
    void update(User user);

    @Delete("DELETE FROM user WHERE id =#{id}")
    void delete(Long id);
}

Result mapping can be customized with @Results and @Result when the returned fields differ from the entity:

@Results({
    @Result(property = "name", column = "name"),
    @Result(property = "age", column = "age")
})
@Select("SELECT name, age FROM user")
List<User> findAll();

The above configuration intentionally omits the id column, which can be verified in a unit test.

For more advanced MyBatis usage, refer to the official documentation or the next article on XML‑based SQL configuration.