mybatis学习二之增删改查

1.增加，并返回主键的id:

配置文件不详细说，见上一篇博客：mybatis学习一之入门示例

在BlogDao中增加接口：

    /**
     * 插入后返回id
     *
     * @param blog
     */
    public void insertCacheId(Blog blog) {
        mapper.insertCacheId(blog);
        this.close();
    }

mapper文件增加接口：

void insertCacheId(Blog blog);

配置文件中增加：

    <!--插入后返回id:select @@identity-->
    <insert id="insertCacheId" parameterType="Blog">
        insert into Blog(id, title, author_id, state, featured, style)
        values
        (#{id}, #{title}, #{authorId}, #{state}, #{featured}, #{style})
        <selectKey resultType="int" keyProperty="id" order="AFTER">
        select @@identity
        </selectKey>
    </insert>

增加测试单元：

    @Test
    public void testInsertCacheBlogId() {
        Blog build = Blog.builder()
                .authorId(1)
                .state("ACTIVE")
                .style("333")
                .featured(false)
                .title("三国演义")
                .build();
        new BlogDao().insertCacheId(build);
        logger.info("after blog is:{}", build);
    }

测试结果：

 

2.查询所有数据，步骤同上：

    public List<Blog> selectAllBlogs() {
        return mapper.selectAllBlogs();
    }

 

 List<Blog> selectAllBlogs();

    <select id="selectAllBlogs" resultType="Blog">
        select * from Blog
    </select>

    @Test
    public void testSelectAllBlogs() {
        final List<Blog> blogs = new BlogDao().selectAllBlogs();
        blogs.stream().forEach(blog -> logger.info(blog));
    }

3.模糊查询

    public List<Blog> selectBlogsByTitle(String title) {
        return mapper.selectBlogsByTitle(title);
    }

 

List<Blog> selectBlogsByTitle(String title);

 

    <select id="selectBlogsByTitle" resultType="Blog">
        select * from Blog where title like concat('%', #{title}, '%')
    </select>

    @Test
    public void testSelectBlogsByTitle() {
        final List<Blog> blogs = new BlogDao().selectBlogsByTitle("三");
        blogs.stream().forEach(blog -> logger.info(blog));
    }

测试结果：

4.多条件查询

    public List<Blog> selectBlogsByCondition(Map<String, Object> map) {
        return mapper.selectBlogsByCondition(map);
    }

 

List<Blog> selectBlogsByCondition(Map<String, Object> map);

 

    <select id="selectBlogsByCondition" resultType="Blog">
        select * from Blog where title like concat('%', #{title}, '%') and state = #{state}
    </select>

 

    @Test
    public void testSelectBlogsByCondition() {
        Map<String, Object> map = new HashMap<>();
        map.put("title", "a");
        map.put("state", "Active");
        final List<Blog> blogs = new BlogDao().selectBlogsByCondition(map);
        blogs.stream().forEach(blog -> logger.info(blog));
    }