mybatisplus的分页、关键字、连表查询

直接看代码

1.controller

/**
* 分页查询数据
*
* @param query 查询对象
* @return PageList 分页对象
*/
@RequestMapping(value = "/json",method = RequestMethod.POST)
public PageList<Brand> json(@RequestBody BrandQuery query)
{
 return brandService.queryPage(query);
}

2.service层

@Autowired
private BrandMapper brandMapper;
@Override
public PageList<Brand> queryPage(BrandQuery query) {
    long total = 0L;
 total = brandMapper.queryPageCount(query);//获取总数据
 if (total == 0) {
 return new PageList<>();
 } else {
 List<Brand> list = brandMapper.queryPageList(query);
 return new PageList<>(total, list);
 }

}


3.mapper

/**
 * 分页数据总的条数
 * @param query
 * @return
 */
long queryPageCount(BrandQuery query);

/**
 * 当前页的分页数据
 * @param query
 * @return
 */
List<Brand> queryPageList(BrandQuery query);

4.映射到BrandMapper.xml中

   <resultMap id="BrandMap" type="Brand">
 <!--封装基本属性-->
 <id column="id" property="id" />
 <result column="name" property="name" />
 <result column="englishName" property="englishName" />
 
 <!--封装关联属性-->
 <association property="productType" javaType="ProductType">
 <id column="pid" property="id" />
 <result column="pname" property="name" />
 </association>
 </resultMap>

 <!--分页数据总的条数-->
 <select id="queryPageCount" resultType="long" parameterType="BrandQuery">
 SELECT
 count(b.id)
 FROM
 t_brand b
 LEFT JOIN t_product_type p ON b.productTypeId = p.id
 <include refid="whereSql"/>

 </select>
 <!--当前页的分页数据-->
 <select id="queryPageList" parameterType="BrandQuery" resultMap="BrandMap">
 SELECT
 b.id,
 b.name,
 b.englishName
 FROM
 t_brand b
 LEFT JOIN t_product_type p ON b.productTypeId = p.id
 <include refid="whereSql"/>
 limit #{start},#{rows}
 </select>

 <!--带条件查询-->
 <sql id="whereSql">
 <where>
 <if test="keyword!=null and keyword!=''">
 b.name like concat('%',#{keyword},'%') or b.description like concat('%',#{keyword},'%')
 </if>
 </where>
 </sql>