第二章分类，推荐，搜索，评价，购物车开发 - 3.5 商品评价 - 实现分页 - 《Java 架构直通车》

引入分页插件依赖

     <dependency>
         <groupId>com.github.pagehelper</groupId>
         <artifactId>pagehelper-spring-boot-starter</artifactId>
         <version>1.3.0</version>
     </dependency>

配置 yml

############################################################
#
# web访问端口号 约定：8088
#
############################################################
server:
port: 8088
tomcat:
 uri-encoding: UTF-8
max-http-header-size: 80KB
############################################################
#
# 配置数据源信息
#
############################################################
spring:
datasource: # 数据源的相关配置
 type: com.zaxxer.hikari.HikariDataSource # 数据源类型：HikariCP
 driver-class-name: com.mysql.cj.jdbc.Driver # mysql驱动
 url: jdbc:mysql://localhost:3306/foodie-shop-dev?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
 username: root
 password: root
 hikari:
   connection-timeout: 30000 # 等待连接池分配连接的最大时长（毫秒），超过这个时长还没可用的连接则发生SQ
   minimum-idle: 5 # 最小连接数
   maximum-pool-size: 20 # 最大连接数
   auto-commit: true # 自动提交
   idle-timeout: 600000 # 连接超时的最大时长（毫秒），超时则被释放（retired），默认:10分钟
   pool-name: DateSourceHikariCP # 连接池名字
   max-lifetime: 1800000 # 连接的生命时长（毫秒），超时而且没被使用则被释放（retired），默认:30分钟
   connection-test-query: SELECT 1
############################################################
#
# mybatis 配置
#
############################################################
mybatis:
type-aliases-package: com.imooc.pojo # 所有POJO类所在包路径
mapper-locations: classpath:mapper/*.xml # mapper映射文件
configuration:
 log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
############################################################
#
# mybatis mapper 配置
#
############################################################
# 通用 Mapper 配置
mapper:
mappers: com.imooc.my.mapper.MyMapper
not-empty: false # 在进行数据库操作的时候，判断表达式 username != null，是否追加 username != ''
identity: MYSQL # 数据库方言
# 分页插件配置
pagehelper:
helperDialect: mysql
supportMethodsArguments: true

使用分页插件，在查询前使用分页插件，原理：统一拦截 sql，为其提供分页功能

在 foodie-dev-service 模块中修改 ItemService 接口的 queryPagedComments 方法

package com.imooc.service;

import com.imooc.pojo.Items;
import com.imooc.pojo.ItemsImg;
import com.imooc.pojo.ItemsParam;
import com.imooc.pojo.ItemsSpec;
import com.imooc.pojo.vo.CommentLevelCountsVO;
import com.imooc.pojo.vo.ItemCommentVO;

import java.util.List;

/**
 * Created by 92578 on 2020/8/22 16:17
 **/
public interface ItemService {

    /**
     * 根据商品 id 查询详情
     *
     * @param itemId
     * @return
     */
    public Items queryItemById(String itemId);

    /**
     * 根据商品 id 查询商品图片列表
     *
     * @param itemId
     * @return
     */
    public List<ItemsImg> queryItemImgList(String itemId);

    /**
     * 根据商品 id 查询商品规格
     *
     * @param itemId
     * @return
     */
    public List<ItemsSpec> queryItemSpecList(String itemId);

    /**
     * 根据商品 id 查询商品参数
     *
     * @param itemId
     * @return
     */
    public ItemsParam queryItemsParam(String itemId);

    /**
     * 根据商品 id 查询商品的评价等级数量
     *
     * @param itemId
     */
    public CommentLevelCountsVO queryCommentCounts(String itemId);

    /**
     * 根据商品 id 查询商品的评价（分页）
     *
     * @param itemId
     * @param level
     * @return
     */
    public List<ItemCommentVO> queryPagedComments(String itemId, Integer level, Integer page, Integer pageSize);
}

分页数据封装到 PagedGridResult.java 传给前端

在 foodie-dev-common 模块下的 com.imooc.utils 包内创建 PagedGridResult 类

package com.imooc.utils;

import java.util.List;

/**
 * 
 * @Title: PagedGridResult.java
 * @Package com.imooc.utils
 * @Description: 用来返回分页Grid的数据格式
 * Copyright: Copyright (c) 2019
 */
public class PagedGridResult {

    private int page;            // 当前页数
    private int total;            // 总页数    
    private long records;        // 总记录数
    private List<?> rows;        // 每行显示的内容

    public int getPage() {
        return page;
    }
    public void setPage(int page) {
        this.page = page;
    }
    public int getTotal() {
        return total;
    }
    public void setTotal(int total) {
        this.total = total;
    }
    public long getRecords() {
        return records;
    }
    public void setRecords(long records) {
        this.records = records;
    }
    public List<?> getRows() {
        return rows;
    }
    public void setRows(List<?> rows) {
        this.rows = rows;
    }
}

在 foodie-dev-service 模块中修改 ItemServiceImpl 类的 queryPagedComments 方法

package com.imooc.service.impl;

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.imooc.enums.CommentLevel;
import com.imooc.mapper.*;
import com.imooc.pojo.*;
import com.imooc.pojo.vo.CommentLevelCountsVO;
import com.imooc.pojo.vo.ItemCommentVO;
import com.imooc.service.ItemService;
import com.imooc.utils.PagedGridResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import tk.mybatis.mapper.entity.Example;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Created by 92578 on 2020/8/22 16:18
 **/
@Service
public class ItemServiceImpl implements ItemService {

    @Autowired
    private ItemsMapper itemsMapper;

    @Autowired
    private ItemsImgMapper itemsImgMapper;

    @Autowired
    private ItemsSpecMapper itemsSpecMapper;

    @Autowired
    private ItemsParamMapper itemsParamMapper;

    @Autowired
    private ItemsCommentsMapper itemsCommentsMapper;

    @Autowired
    private ItemsMapperCustom itemsMapperCustom;

    /**
     * 根据商品 id 查询详情
     *
     * @param itemId
     * @return
     */
    @Transactional(propagation = Propagation.SUPPORTS)
    @Override
    public Items queryItemById(String itemId) {
        return itemsMapper.selectByPrimaryKey(itemId);
    }

    /**
     * 根据商品 id 查询商品图片列表
     *
     * @param itemId
     * @return
     */
    @Transactional(propagation = Propagation.SUPPORTS)
    @Override
    public List<ItemsImg> queryItemImgList(String itemId) {
        Example itemsImgExp = new Example(ItemsImg.class);
        Example.Criteria criteria = itemsImgExp.createCriteria();
        criteria.andEqualTo("itemId", itemId);

        return itemsImgMapper.selectByExample(itemsImgExp);
    }

    /**
     * 根据商品 id 查询商品规格
     *
     * @param itemId
     * @return
     */
    @Transactional(propagation = Propagation.SUPPORTS)
    @Override
    public List<ItemsSpec> queryItemSpecList(String itemId) {
        Example itemsSpecExp = new Example(ItemsSpec.class);
        Example.Criteria criteria = itemsSpecExp.createCriteria();
        criteria.andEqualTo("itemId", itemId);

        return itemsSpecMapper.selectByExample(itemsSpecExp);
    }

    /**
     * 根据商品 id 查询商品参数
     *
     * @param itemId
     * @return
     */
    @Transactional(propagation = Propagation.SUPPORTS)
    @Override
    public ItemsParam queryItemsParam(String itemId) {
        Example itemsParamExp = new Example(ItemsParam.class);
        Example.Criteria criteria = itemsParamExp.createCriteria();
        criteria.andEqualTo("itemId", itemId);

        return itemsParamMapper.selectOneByExample(itemsParamExp);
    }

    /**
     * 根据商品 id 查询商品的评价等级数量
     *
     * @param itemId
     */
    @Transactional(propagation = Propagation.SUPPORTS)
    @Override
    public CommentLevelCountsVO queryCommentCounts(String itemId) {
        Integer goodCounts = getCommentCounts(itemId, CommentLevel.GOOD.type);
        Integer normalCounts = getCommentCounts(itemId, CommentLevel.NORMAL.type);
        Integer badCounts = getCommentCounts(itemId, CommentLevel.BAD.type);
        Integer totalCounts = goodCounts + normalCounts + badCounts;

        CommentLevelCountsVO countsVO = new CommentLevelCountsVO();
        countsVO.setTotalCounts(totalCounts);
        countsVO.setGoodCounts(goodCounts);
        countsVO.setNormalCounts(normalCounts);
        countsVO.setBadCounts(badCounts);

        return countsVO;
    }

    /**
     * 根据商品 id 查询商品的评价（分页）
     *
     * @param itemId
     * @param level
     * @return
     */
    @Transactional(propagation = Propagation.SUPPORTS)
    @Override
    public PagedGridResult queryPagedComments(String itemId, Integer level, Integer page, Integer pageSize) {
        Map<String, Object> map = new HashMap<>();
        map.put("itemId", itemId);
        map.put("level", level);

        /**
         * page: 第几页
         * pageSize: 每页显示条数
         */
        PageHelper.startPage(page, pageSize);

        List<ItemCommentVO> list = itemsMapperCustom.queryItemComments(map);

        return setterPagedGrid(list, page);
    }

    private PagedGridResult setterPagedGrid(List<?> list, Integer page) {
        PageInfo<?> pageList = new PageInfo<>(list);
        PagedGridResult grid = new PagedGridResult();
        grid.setPage(page);
        grid.setRows(list);
        grid.setTotal(pageList.getPages());
        grid.setRecords(pageList.getTotal());
        return grid;
    }

    @Transactional(propagation = Propagation.SUPPORTS)
    Integer getCommentCounts(String itemId, Integer level) {
        ItemsComments condition = new ItemsComments();
        condition.setItemId(itemId);
        if (level != null) {
            condition.setCommentLevel(level);
        }

        return itemsCommentsMapper.selectCount(condition);
    }
}

在 foodie-dev-service 模块中修改 ItemService 接口的 queryPagedComments 方法

package com.imooc.service;

import com.imooc.pojo.Items;
import com.imooc.pojo.ItemsImg;
import com.imooc.pojo.ItemsParam;
import com.imooc.pojo.ItemsSpec;
import com.imooc.pojo.vo.CommentLevelCountsVO;
import com.imooc.utils.PagedGridResult;

import java.util.List;

/**
 * Created by 92578 on 2020/8/22 16:17
 **/
public interface ItemService {

    /**
     * 根据商品 id 查询详情
     *
     * @param itemId
     * @return
     */
    public Items queryItemById(String itemId);

    /**
     * 根据商品 id 查询商品图片列表
     *
     * @param itemId
     * @return
     */
    public List<ItemsImg> queryItemImgList(String itemId);

    /**
     * 根据商品 id 查询商品规格
     *
     * @param itemId
     * @return
     */
    public List<ItemsSpec> queryItemSpecList(String itemId);

    /**
     * 根据商品 id 查询商品参数
     *
     * @param itemId
     * @return
     */
    public ItemsParam queryItemsParam(String itemId);

    /**
     * 根据商品 id 查询商品的评价等级数量
     *
     * @param itemId
     */
    public CommentLevelCountsVO queryCommentCounts(String itemId);

    /**
     * 根据商品 id 查询商品的评价（分页）
     *
     * @param itemId
     * @param level
     * @return
     */
    public PagedGridResult queryPagedComments(String itemId, Integer level, Integer page, Integer pageSize);
}

在 foodie-dev-api 模块下的 com.imooc.controller 包内创建 BaseController 类

package com.imooc.controller;

import org.springframework.stereotype.Controller;

/**
 * @author 92578
 * @since 1.0
 */
@Controller
public class BaseController {
    public static final Integer COMMENT_PAGE_SIZE = 10;
}

在 foodie-dev-api 模块下的 ItemsController 类中添加 comments 方法

package com.imooc.controller;

import com.imooc.pojo.Items;
import com.imooc.pojo.ItemsImg;
import com.imooc.pojo.ItemsParam;
import com.imooc.pojo.ItemsSpec;
import com.imooc.pojo.vo.CommentLevelCountsVO;
import com.imooc.pojo.vo.ItemInfoVO;
import com.imooc.service.ItemService;
import com.imooc.utils.IMOOCJSONResult;
import com.imooc.utils.PagedGridResult;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

/**
 * Created by 92578 on 2020/8/22 16:30
 **/
@Api(value = "商品接口", tags = {"商品信息展示的相关接口"})
@RestController
@RequestMapping("items")
public class ItemsController extends BaseController {

    @Autowired
    private ItemService itemService;

    @ApiOperation(value = "查询商品详情", notes = "查询商品详情", httpMethod = "GET")
    @GetMapping("/info/{itemId}")
    public IMOOCJSONResult info(
            @ApiParam(name = "itemId", value = "商品 id", required = true)
            @PathVariable String itemId) {
        if (StringUtils.isBlank(itemId)) {
            return IMOOCJSONResult.errorMsg(null);
        }

        Items item = itemService.queryItemById(itemId);
        List<ItemsImg> itemsImgList = itemService.queryItemImgList(itemId);
        List<ItemsSpec> itemsSpecList = itemService.queryItemSpecList(itemId);
        ItemsParam itemsParam = itemService.queryItemsParam(itemId);

        ItemInfoVO itemInfoVO = new ItemInfoVO();
        itemInfoVO.setItem(item);
        itemInfoVO.setItemImgList(itemsImgList);
        itemInfoVO.setItemSpecList(itemsSpecList);
        itemInfoVO.setItemParams(itemsParam);

        return IMOOCJSONResult.ok(itemInfoVO);
    }

    @ApiOperation(value = "查询商品评价等级", notes = "查询商品评价等级", httpMethod = "GET")
    @GetMapping("/commentLevel")
    public IMOOCJSONResult commentLevel(
            @ApiParam(name = "itemId", value = "商品 id", required = true)
            @RequestParam String itemId) {
        if (StringUtils.isBlank(itemId)) {
            return IMOOCJSONResult.errorMsg(null);
        }

        CommentLevelCountsVO countsVO = itemService.queryCommentCounts(itemId);

        return IMOOCJSONResult.ok(countsVO);
    }

    @ApiOperation(value = "查询商品评论", notes = "查询商品评论", httpMethod = "GET")
    @GetMapping("/comments")
    public IMOOCJSONResult comments(
            @ApiParam(name = "itemId", value = "商品 id", required = true)
            @RequestParam String itemId,
            @ApiParam(name = "level", value = "评价等级", required = false)
            @RequestParam Integer level,
            @ApiParam(name = "page", value = "查询下一页的第几页", required = false)
            @RequestParam Integer page,
            @ApiParam(name = "pageSize", value = "分页的每一页显示的条数", required = false)
            @RequestParam Integer pageSize) {
        if (StringUtils.isBlank(itemId)) {
            return IMOOCJSONResult.errorMsg(null);
        }

        if (page == null) {
            page = 1;
        }

        if (pageSize == null) {
            pageSize = COMMENT_PAGE_SIZE;
        }

        PagedGridResult grid = itemService.queryPagedComments(itemId, level, page, pageSize);

        return IMOOCJSONResult.ok(grid);
    }
}

启动项目，打开浏览器，访问 http://localhost:8080/foodie-shop/item.html?itemId=cake-1001
点击“全部评价”，评价内容加载成功

点击“第二页”，内容也是可以加载成功的

点击“好评”，会只显示好评数据，中评和差评同理。

好评记录

中评记录

差评记录