MyBatis动态SQL（二）：IF语句

动态SQL--IF语句

1、BlogMapper

public interface BlogMapper {

    //查询博客
    List<Blog> queryBlogIF(Map map);
}

2、BlogMapper.xml

  <select id="queryBlogIF" parameterType="map" resultType="blog">
        select * from mybatis.blog 
        <where>
            <if test="title!=null">
                and title=#{title}
            </if>
            <if test="author!=null">
                and author=#{author}
            </if>
        </where>
    </select>

3、测试

   @Test
    public void queryBlogIFTest(){
        SqlSession sqlSession = MyBatisUtils.getSqlSession();
        BlogMapper mapper = sqlSession.getMapper(BlogMapper.class);

        HashMap map = new HashMap();
        map.put("title","算法");
        List<Blog> blogs = mapper.queryBlogIF(map);
        for (Blog blog:blogs) {
            System.out.println(blog);
        }
        sqlSession.close();
    }

 

详情参考：https://mybatis.org/mybatis-3/zh/dynamic-sql.html