动态SQL

最新推荐文章于 2025-12-14 21:11:55 发布

原创最新推荐文章于 2025-12-14 21:11:55 发布 · 88 阅读

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<?xml version="1.0" encoding="UTF8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--namespace命名空间：与那个接口类文件产生交集，相当于实现那个接口-->
<mapper namespace="com.kuang.dao.BlogMapper">
<insert id="addBook" parameterType="Blog">
insert into mybatis.blog (id,title,author,create_Time,views) Values(#{id},#{title},#{author},#{createTime},#{views})
</insert>

</mapper>

package com.kuang.pojo;

import lombok.Data;

import java.util.Date;
@Data
public class Blog {
    private String id;
    private String title;
    private String author;
    private Date createTime;
    private int views;

}

接口

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

mapper

<!--    //动态查询If-->
    <select id="queryBlog" parameterType="map" resultType="Blog">
        select * from mybatis.blog where 1=1
        <if test="title!=null">
            And title =#{title}
        </if>
        <if test="author!=null">
            And author =#{author}
        </if>
    </select>

测试

    @Test
    public void queryBlog(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        BlogMapper mapper = sqlSession.getMapper(BlogMapper.class);
        HashMap<String, Object> map = new HashMap<String, Object>();
        map.put("title","Mybatis");
        List<Blog> blogs = mapper.queryBlog(map);
        for (Blog blog : blogs) {
            System.out.println(blog);
        }


        sqlSession.close();
    }