Switch from MyBatis Annotations to XML in Spring Boot: Step‑by‑Step Guide

In the previous article we introduced integrating MyBatis with Spring Boot using annotations. This tutorial shows how to switch to the XML configuration style.

Hands‑on

The article assumes you already know the basics of MyBatis integration; you can refer to the previous tutorial for that.

The sample project can be obtained from the chapter3-5 directory in the repository linked at the end.

Step 1 : Add a mapper‑scan annotation to the main application class.

@MapperScan("com.didispace.chapter36.mapper")
@SpringBootApplication
public class Chapter36Application {

    public static void main(String[] args) {
        SpringApplication.run(Chapter36Application.class, args);
    }
}

Step 2 : Create a UserMapper interface in the scanned package.

public interface UserMapper {

    User findByName(@Param("name") String name);

    int insert(@Param("name") String name, @Param("age") Integer age);
}

Step 3 : Specify the location of XML mapper files in application.properties (or yaml) using the mybatis.mapper-locations property.

mybatis.mapper-locations=classpath:mapper/*.xml

Step 4 : Create the XML mapper file UserMapper.xml under src/main/resources/mapper:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.didispace.chapter36.mapper.UserMapper">
    <select id="findByName" resultType="com.didispace.chapter36.entity.User">
        SELECT * FROM USER WHERE NAME = #{name}
    </select>

    <insert id="insert">
        INSERT INTO USER(NAME, AGE) VALUES(#{name}, #{age})
    </insert>
</mapper>

To verify the configuration, run the following unit test which inserts a record and queries it back.

@Slf4j
@RunWith(SpringRunner.class)
@SpringBootTest
@Transactional
public class Chapter36ApplicationTests {

    @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());
    }
}

If the test fails, compare your code with the complete example in the repository.

Resources:

GitHub: https://github.com/dyc87112/SpringBoot-Learning/

Gitee: https://gitee.com/didispace/SpringBoot-Learning/