[Java知识库]SpringBoot之使用配置文件方式整合MyBatis

一、使用配置文件方式整合MyBatis

1、创建Mapper接口文件：@Mapper

    //主要内容
     @Mapper
     public interface ArticalMapper{

         //根据id查询文章（包含对应的评论）
        public Article selectArticle(Integer id);
     }

2、创建XML映射文件：编写对应的SQL语句

根据实体类来创建

public class Article{
    private Integer id;
    private String title;
    private String content;
    private List<Comment>commentList;
}

public class Comment{
    private Integer ID;
    private String content;
    private IntegeraId;
}

对应SQL语句如下所示：

<resultMap id="ac" type="com.itheima.domain.Article ">
     <id property="id" column="id"> </id>
     <result property="title" column="title"> </result>
     <result property="content" column="content"> </result>
     <collection property="commentList" ofType="com.itheima.domain.Comment">
          <id property="id" column="c_id">  </id>
          <result property="content" column="content"> </result>
          <result property="author" column="author"> </result>
          <result property="aid" column="aid"> </result>
     </collection>
</resultMap>

<select id="selectArticle" resultMap="ac" parameterType="int">
     SELECT a.*, c.id c_id, c.content, c.author, c.a_id FROM t_article a, t_comment c WHERE c.a_id=a.id and a.id=#{a.id}
</select>

3、在全局文件中配置XML映射文件路径以及实体类别名映射路径

   //配置mybatis的xml配置文件路径
   mybatis.mapper-locations=classpath:mapper/ArticleMapper.xml

   //配置xml映射文件中指定的实体类别名
   mybatis.type-aliases-package=com.itheima.domain.

4、编写测试方法进行接口方法测试及整合测试

   @Test
   public void contextLoads(){
        Article article=articleMapper.selectArticle(2);
        System.out.println(article);
   }