从mvn repo官网查看mybatis-spring-boot-starter对应的各版本号,如图:

从mybatis-spring官网,查看集成Spring framework对应的版本匹配规则,如图:

mybatis-spring官网url: https://mybatis.org/spring/zh/index.html

结合1和2点,判断选择mybatis的集成版本为2.2.2(根据spring framwork和jdk对应版本去匹配mybatis相应版本,然后选择版本较新且使用相对较多的版本)

根据官网的集成文档进行相应的配置集成

配置mybaits的核心组件SqlSessionFactoryBean

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@Configuration
@MapperScan("pers.xiaotian.sgg")
class MyBatisConfig {
    @Autowired
    //数据源用topic8的
    private DataSource dataSource;

    @Bean
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        factoryBean.setDataSource(dataSource);
        factoryBean.setMapperLocations(resolver.getResources("classpath:mapperConfig/**.xml"));
        return factoryBean.getObject();
    }
}

创建对应表的xml文件和bean接口实例

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@Component
interface UserMapper{
    User selectOne();
}
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<?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="pers.xiaotian.sgg.UserMapper">
    <select id="selectOne" resultType="pers.xiaotian.entity.User">
        select *
        from user
    </select>
</mapper>

使用测试类进行测试验证

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public class Topic11 {

    public static void main(String[] args) {
        ApplicationContext ioc = new AnnotationConfigApplicationContext("pers.xiaotian.sgg");
        UserMapper userMapper = (UserMapper) ioc.getBean("userMapper");
        System.out.println(userMapper.selectOne().toString());

    }
}

运行结果,如图:

解决userName数据未匹配的方式

sql语句设置别名,代码调整如下:

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<select id="selectOne" resultType="pers.xiaotian.entity.User">
    select id, user_name userName, age
    from user
</select>

运行结果,如图:

添加字段转换Mappper方式,代码如下:

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<?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="pers.xiaotian.sgg.UserMapper">
    <resultMap id="baseMap"  type="pers.xiaotian.entity.User">
        <id column="id" property="id" />
        <result column="user_name" property="userName"/>
        <result column="age" property="age" />
    </resultMap>
    <select id="selectOne" resultMap="baseMap">
        select *
        from user
    </select>
</mapper>

运行结果,如图:

SqlSessionFactoryBean里面配置对应映射关系,此配置设置后全局生效,代码如下:

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@Bean
public SqlSessionFactory sqlSessionFactory() throws Exception {
    SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
    PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
    factoryBean.setDataSource(dataSource);
    factoryBean.setMapperLocations(resolver.getResources("classpath:mapperConfig/**.xml"));
    org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
    configuration.setMapUnderscoreToCamelCase(true);
    factoryBean.setConfiguration(configuration);
    return factoryBean.getObject();
}

运行结果,如图: