mybatisplus分页使用

MyBatis Plus 实现多表分页查询_骑驴的小牧童的博客-CSDN博客_mybatis-plus多表分页

最简单的 MyBatis Plus 的多表联接、分页查询实现方法_IT小村的博客-CSDN博客_mybatisplus多表联查

Mybatis-Plus中分页插件PaginationInterceptor, MybatisPlusInterceptor在SpringBoot中的使用_Sakura_Lu_的博客-CSDN博客_paginationinterceptor

项目中有用到 mybatis-plus(mbp) 进行分页的需求，所以笔记记录下。

一.声明配置类

@Configuration
@EnableTransactionManagement(proxyTargetClass = true)
public class MybatisPlusConfiguration {

    /**
     * 分页插件
     */
    @Bean
    public MybatisPlusInterceptor paginationInnerInterceptor() {

        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        //声明针对分页的拦截器
        PaginationInnerInterceptor pageInterceptor = new PaginationInnerInterceptor();
        //声明数据库类型
        pageInterceptor.setDbType(DbType.MYSQL);
        //添加到拦截器链中
        interceptor.addInnerInterceptor(pageInterceptor);
        return interceptor;
    }
}

二.实体类

@Data
@EqualsAndHashCode(callSuper = false)
@Accessors(chain = true)
public class RuleConfiguration implements Serializable {

    private static final long serialVersionUID=1L;

    /**
     * 自增主键ID
     */
    @TableId(value = "id", type = IdType.AUTO)
    private Long id;

    /**
     * 规则名称
     */
    @TableField("name")
    private String name;


    public static final String ID = "id";

    public static final String NAME = "name";
}

实体类中须包含 @TableField 等注解

三.mapper

public interface RuleConfigurationMapper extends BaseMapper<RuleConfiguration> {

    /**
     * 规则分页
     *
     * @param page 分页对象
     * @param name 规则名称
     * @return
     */
    List<ScheduleRulePageDTO> scheduleRulePage(Page page, @Param("name") String name);
}

方法参数须带上 Page 对象

四.Service

@Service
@Slf4j
public class RuleConfigurationServiceImpl implements RuleConfigurationService {

    @Autowired
    private RuleConfigurationMapper RuleConfigurationMapper;

    @Override
    public void page(PageReq req) {

        Page<RuleConfiguration> page = new Page<>(req.getPageNum(), req.getPageSize());
        List<RulePageDTO> RulePage = RuleConfigurationMapper.scheduleRulePage(page, req.getName());
    }
}

声明 Page 对象并且设置 分页数 和 分页大小 属性，分页的方法传入 page 和查询条件即可完成分页。

五.结果

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6d5a95f6] was not registered for synchronization because synchronization is not active
//拦截器对sql进行相关拦截
2022-04-08 10:17:30.441  WARN 27080 --- [nio-8300-exec-5] c.b.m.e.p.i.PaginationInnerInterceptor   : optimize this sql to a count sql has exception, sql:"SELECT
            t1.id,
            t1.name
        FROM
            rule_configuration  t1 
        ORDER BY t1.updated_at DESC", exception:
null

//拼接 Limit 参数
2022-04-08 10:17:30.450 DEBUG 27080 --- [nio-8300-exec-5] c.m.s.m.s.I.scheduleRulePage             : ==>  Preparing: SELECT t1.id, t1.name FROM rule_configuration t1 ORDER BY t1.updated_at DESC LIMIT ?
2022-04-08 10:17:30.450 DEBUG 27080 --- [nio-8300-exec-5] c.m.s.m.s.I.scheduleRulePage             : ==> Parameters: 10(Long)
2022-04-08 10:17:30.456 DEBUG 27080 --- [nio-8300-exec-5] c.m.s.m.s.I.scheduleRulePage             : <==      Total: 1

从日志可以看出，PaginationInnerInterceptor会对包含page的参数的sql进行拦截并重新拼接Limit参数
不过手动分页也值得考虑~