引入依赖

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

application.yml配置

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#mybatis的相关配置
mybatis:
  #mapper配置文件
  mapper-locations: classpath:mybatis/mapper/*.xml
  type-aliases-package: com.ledao.entity
  #开启驼峰命名
  configuration:
    map-underscore-to-camel-case: true

加入@MapperScan注解

在项目的启动类中加入@MapperScan注解，这样就可以指定要扫描的Mapper类的包的路径了

img

项目代码示例

以对一个博客类进行操作为例

Blog类

已省略setter和getter方法

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package com.ledao.entity;
 
import java.util.Date;
 
/**
 * 博客实体
 *
 * @author LeDao
 * @company
 * @create 2020-09-11 00:08
 */
public class Blog {
 
    /**
     * id
     */
    private Integer id;
    /**
     * 标题
     */
    private String title;
    /**
     * 摘要
     */
    private String summary;
    /**
     * 内容
     */
    private String content;
    /**
     * 发布时间
     */
    private Date releaseDate;
    /**
     * 点击次数
     */
    private Integer click;
    /**
     * 博客类别id
     */
    private Integer blogTypeId;
    /**
     * 博客类别
     */
    private BlogType blogType;
    /**
     * 博客里存在的第一张图片，主要用于列表展示的缩略图
     */
    private String imageName;
    /**
     * 博客数量 非博客实际属性 主要是 根据发布日期归档查询数量用到
     */
    private Integer blogCount;
    /**
     * 发布日期的字符串 只取年和月
     */
    private String releaseDateStr;
    /**
     * 该类型的博客数量
     */
    private Integer blogNum;
    /**
     * 用于判断当前IP是否点赞过这篇博客
     */
    private Integer isLike;
    /**
     * 点赞数
     */
    private Integer likeNum;
    /**
     * 是否是导航条文章（0或空代表不是，1代表是）
     */
    private Integer isMenuBlog;
    /**
     * 设置成为导航条文章的时间
     */
    private Date setMenuBlogDate;
}

BlogMapper接口

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package com.ledao.mapper;
 
import com.ledao.entity.Blog;
 
import java.util.List;
import java.util.Map;
 
/**
 * 博客Mapper接口
 *
 * @author LeDao
 * @company
 * @create 2020-09-11 00:11
 */
public interface BlogMapper {
 
    /**
     * 分页分条件查询博客
     *
     * @param map
     * @return
     */
    List<Blog> list(Map map);
 
    /**
     * 获取记录数
     *
     * @param map
     * @return
     */
    Long getCount(Map map);
 
    /**
     * 添加博客
     *
     * @param blog
     * @return
     */
    Integer add(Blog blog);
 
    /**
     * 修改博客
     *
     * @param blog
     * @return
     */
    Integer update(Blog blog);
 
    /**
     * 根据id删除博客
     *
     * @param id
     * @return
     */
    Integer delete(Integer id);
 
    /**
     * 根据id查找博客
     *
     * @param id
     * @return
     */
    Blog findById(Integer id);
 
    /**
     * 根据日期分月分组查询
     *
     * @return
     */
    List<Blog> countList();
 
    /**
     * 根据博客类型查询博客
     *
     * @param blogTypeId
     * @return
     */
    List<Blog> findByBlogTypeId(Integer blogTypeId);
 
    /**
     * 获取上一篇博客
     *
     * @param id
     * @return
     */
    Blog getPreviousBlog(Integer id);
 
    /**
     * 获取下一篇博客
     *
     * @param id
     * @return
     */
    Blog getNextBlog(Integer id);
 
    /**
     * 获取导航条文章（根据设置时间升序排列）
     *
     * @return
     */
    List<Blog> getMenuBlogList();
}

BlogMapper的XML文件

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<?xml version="1.0" encoding="UTF-8" ?>
<!--suppress ALL-->
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.ledao.mapper.BlogMapper">
    <resultMap id="BlogResult" type="Blog">
        <result property="id" column="id"/>
        <result property="title" column="title"/>
        <result property="summary" column="summary"/>
        <result property="releaseDate" column="releaseDate"/>
        <result property="click" column="click"/>
        <result property="content" column="content"/>
        <result property="blogTypeId" column="blogTypeId"/>
        <result property="isMenuBlog" column="isMenuBlog"/>
        <result property="setMenuBlogDate" column="setMenuBlogDate"/>
    </resultMap>
    <select id="list" parameterType="map" resultMap="BlogResult">
        select *
        from t_blog
        <where>
            <if test="title != null and title != ''">
                and title like #{title}
            </if>
            <if test="blogTypeId != null">
                and blogTypeId = #{blogTypeId}
            </if>
            <if test="isMenuBlog != null">
                and isMenuBlog = #{isMenuBlog}
            </if>
            <if test="isMenuBlogKey != null">
                and isMenuBlog != 1
            </if>
            <if test="releaseDateStr != null and releaseDateStr != ''">
                and date_format(releaseDate, '%Y年%m月') = #{releaseDateStr}
            </if>
        </where>
        <if test="sortByReleaseDate == null">
            order by releaseDate desc
        </if>
        <if test="start != null and size != null">
            limit #{start},#{size}
        </if>
    </select>
    <select id="getCount" parameterType="map" resultType="java.lang.Long">
        select count(*)
        from t_blog
        <where>
            <if test="title != null and title != ''">
                and title like #{title}
            </if>
            <if test="blogTypeId != null">
                and blogTypeId = #{blogTypeId}
            </if>
            <if test="isMenuBlog != null">
                and isMenuBlog = #{isMenuBlog}
            </if>
            <if test="isMenuBlogKey != null">
                and isMenuBlog != 1
            </if>
            <if test="releaseDateStr != null and releaseDateStr != ''">
                and date_format(releaseDate, '%Y年%m月') = #{releaseDateStr}
            </if>
        </where>
    </select>
    <insert id="add" parameterType="Blog">
        insert into t_blog (title, summary, content, releaseDate, click, blogTypeId,isMenuBlog)
        values (#{title}, #{summary}, #{content}, now(), 0, #{blogTypeId},0);
    </insert>
    <update id="update" parameterType="Blog">
        update t_blog
        <set>
            <if test="title != null and title != ''">
                title=#{title},
            </if>
            <if test="summary != null and summary != ''">
                summary=#{summary},
            </if>
            <if test="content != null and content != ''">
                content=#{content},
            </if>
            <if test="click != null">
                click=#{click},
            </if>
            <if test="blogTypeId != null">
                blogTypeId=#{blogTypeId},
            </if>
            <if test="isMenuBlog != null">
                isMenuBlog = #{isMenuBlog},
            </if>
            <if test="setMenuBlogDate != null">
                setMenuBlogDate=now(),
            </if>
        </set>
        where id = #{id}
    </update>
    <delete id="delete" parameterType="integer">
        delete
        from t_blog
        where id = #{id}
    </delete>
    <select id="findById" parameterType="integer" resultMap="BlogResult">
        select *
        from t_blog
        where id = #{id}
    </select>
    <select id="countList" resultMap="BlogResult">
        select date_format(releaseDate, '%Y年%m月') as releaseDateStr, count(*) as blogCount
        from t_blog where isMenuBlog=0
        group by date_format(releaseDate, '%Y年%m月')
        order by date_format(releaseDate, '%Y年%m月') desc
    </select>
    <select id="findByBlogTypeId" parameterType="integer" resultMap="BlogResult">
        select *
        from t_blog
        where blogTypeId = #{blogTypeId}
        order by releaseDate desc
    </select>
 
    <select id="getPreviousBlog" parameterType="integer" resultType="com.ledao.entity.Blog">
        SELECT *
        FROM t_blog
        WHERE id &lt;
              #{id}
        ORDER BY id DESC
        LIMIT 1;
    </select>
 
    <select id="getNextBlog" parameterType="integer" resultType="com.ledao.entity.Blog">
        SELECT *
        FROM t_blog
        WHERE id &gt;
              #{id}
        ORDER BY id asc
        LIMIT 1;
    </select>
 
    <select id="getMenuBlogList" resultMap="BlogResult">
        select *
        from t_blog
        where isMenuBlog = 1
        order by setMenuBlogDate asc
    </select>
</mapper>

BlogService接口

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package com.ledao.service;
 
import com.ledao.entity.Blog;
 
import java.util.List;
import java.util.Map;
 
/**
 * 博客Service接口
 *
 * @author LeDao
 * @company
 * @create 2020-09-11 00:33
 */
public interface BlogService {
 
    /**
     * 分页分条件查询博客
     *
     * @param map
     * @return
     */
    List<Blog> list(Map map);
 
    /**
     * 获取记录数
     *
     * @param map
     * @return
     */
    Long getCount(Map map);
 
    /**
     * 添加博客
     *
     * @param blog
     * @return
     */
    Integer add(Blog blog);
 
    /**
     * 修改博客
     *
     * @param blog
     * @return
     */
    Integer update(Blog blog);
 
    /**
     * 根据id删除博客
     *
     * @param id
     * @return
     */
    Integer delete(Integer id);
 
    /**
     * 根据id查找博客
     *
     * @param id
     * @return
     */
    Blog findById(Integer id);
 
    /**
     * 根据日期分月分组查询
     *
     * @return
     */
    List<Blog> countList();
 
    /**
     * 根据博客类型查询博客
     *
     * @param blogTypeId
     * @return
     */
    List<Blog> findByBlogTypeId(Integer blogTypeId);
 
    /**
     * 获取上一篇博客
     *
     * @param id
     * @return
     */
    Blog getPreviousBlog(Integer id);
 
    /**
     * 获取下一篇博客
     *
     * @param id
     * @return
     */
    Blog getNextBlog(Integer id);
 
    /**
     * 获取导航条文章（根据设置时间升序排列）
     *
     * @return
     */
    List<Blog> getMenuBlogList();
}

BlogService接口的实现类

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package com.ledao.service.impl;
 
import com.ledao.entity.Blog;
import com.ledao.mapper.BlogMapper;
import com.ledao.service.BlogService;
import org.springframework.stereotype.Service;
 
import javax.annotation.Resource;
import java.util.List;
import java.util.Map;
 
/**
 * 博客Service接口实现类
 *
 * @author LeDao
 * @company
 * @create 2020-09-11 00:34
 */
@Service("blogService")
public class BlogServiceImpl implements BlogService {
 
    @Resource
    private BlogMapper blogMapper;
 
    @Override
    public List<Blog> list(Map map) {
        return blogMapper.list(map);
    }
 
    @Override
    public Long getCount(Map map) {
        return blogMapper.getCount(map);
    }
 
    @Override
    public Integer add(Blog blog) {
        return blogMapper.add(blog);
    }
 
    @Override
    public Integer update(Blog blog) {
        return blogMapper.update(blog);
    }
 
    @Override
    public Integer delete(Integer id) {
        return blogMapper.delete(id);
    }
 
    @Override
    public Blog findById(Integer id) {
        return blogMapper.findById(id);
    }
 
    @Override
    public List<Blog> countList() {
        return blogMapper.countList();
    }
 
    @Override
    public List<Blog> findByBlogTypeId(Integer blogTypeId) {
        return blogMapper.findByBlogTypeId(blogTypeId);
    }
 
    @Override
    public Blog getPreviousBlog(Integer id) {
        return blogMapper.getPreviousBlog(id);
    }
 
    @Override
    public Blog getNextBlog(Integer id) {
        return blogMapper.getNextBlog(id);
    }
 
    @Override
    public List<Blog> getMenuBlogList() {
        return blogMapper.getMenuBlogList();
    }
}