Mybatis 框架 ( 五 ) 分页

4.6.分页

Mybatis-plus 内置分页插件, 并支持多种数据库

官网 : 分页插件 | MyBatis-Plus (baomidou.com)

4.6.1.增加拦截器

通过 @MapperScan 指定 mapper接口的路径

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
@MapperScan("com.yuan.mapper")
public class MybatisPlusConfig {/*** 添加分页插件*/@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));//如果配置多个插件,切记分页最后添加//interceptor.addInnerInterceptor(new PaginationInnerInterceptor()); 如果有多数据源可以不配具体类型 否则都建议配上具体的DbTypereturn interceptor;}}

4.6.2.封装分页信息

准备封装用于分页查询的工具类 BrandInfoPage

import lombok.Data;@Data
public class BrandInfoPage {private Integer pageNo = 1;private Integer pageSize = 10;}

4.6.3.serviceImpl

服务层查询

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.yuan.entity.BrandInfo;
import com.yuan.mapper.BrandInfoMapper;
import com.yuan.page.BrandInfoPage;
import com.yuan.service.BrandInfoService;
import org.springframework.stereotype.Service;@Service
public class BrandInfoServiceImpl extends ServiceImpl<BrandInfoMapper, BrandInfo>implements BrandInfoService{@Overridepublic IPage<BrandInfo> listForPage(BrandInfoPage page) {IPage<BrandInfo> pageInfo = new Page<>();// 设置页号pageInfo.setCurrent(page.getPageNo());// 设置页大小pageInfo.setSize(page.getPageSize());return baseMapper.selectPage(pageInfo, null);}
}

baseMapper.selectPage(pageInfo, null); 第二个参数为 QueryWrapper 用于条件查询

4.6.4.返回 Controller类

分析数据

import com.baomidou.mybatisplus.core.metadata.IPage;
import com.yuan.entity.BrandInfo;
import com.yuan.page.BrandInfoPage;
import com.yuan.service.BrandInfoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
public class BrandInfoController {@Autowiredprivate BrandInfoService brandInfoService;@RequestMapping("/brandInfo/query")public IPage<BrandInfo> query(BrandInfoPage page){System.out.println("page = " + page);IPage<BrandInfo> list = brandInfoService.listForPage(page);System.out.println("list = " + list);System.out.println("分页数据集合 = " + list.getRecords());System.out.println("当前页号 = " + list.getCurrent());System.out.println("每页最多多少条 = " + list.getSize());System.out.println("总记录数 = " + list.getTotal());System.out.println("总页数 = " + list.getPages());}
}

4.6.5.增加条件查询

4.6.5.1.修改 page类

import lombok.Data;@Data
public class BrandInfoPage {private Integer pageNo = 1;private Integer pageSize = 10;/*** 中文名 模糊*/private String cnName;/*** 英文名 精确*/private String enName;
}

4.6.5.2.修改ServiceImpl

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.yuan.entity.BrandInfo;
import com.yuan.mapper.BrandInfoMapper;
import com.yuan.page.BrandInfoPage;
import com.yuan.service.BrandInfoService;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;@Service
public class BrandInfoServiceImpl extends ServiceImpl<BrandInfoMapper, BrandInfo>implements BrandInfoService{@Overridepublic IPage<BrandInfo> listForPage(BrandInfoPage page) {IPage<BrandInfo> pageInfo = new Page<>();// 设置页号pageInfo.setCurrent(page.getPageNo());// 设置页大小pageInfo.setSize(page.getPageSize());LambdaQueryWrapper<BrandInfo> queryWrapper = new LambdaQueryWrapper<BrandInfo>().like(page.getCnName() != null, BrandInfo::getBrandCnName, page.getCnName()).eq( !StringUtils.isEmpty(page.getEnName()), BrandInfo::getBrandEnName, page.getEnName()).orderByAsc(BrandInfo::getBrandNum);return baseMapper.selectPage(pageInfo, queryWrapper);}
}