EasyExcel导出数据，解决慢sql，漏数据，重复数据问题（一）

大家思考一下，在导出excel时是否会出现如下几个常见问题

慢sql问题
漏数据，缺数据问题
数据重复

那到底该如何解决呢？下面我们一起来看看我的实现吧！

代码示例

controller入口
分页查询2000条数据，分批次导出。

 /***下载自动续费* @author youlu* @date 2022/11/21 14:32* @param response* @return com.smy.ucc.common.JsonMessage*/@GetMapping("/downloadRenewalSign")public void downloadRenewalSign(HttpServletResponse response, RenewalSignAdminReq req) throws Exception {this.checkDownloadParam(req);response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");response.setCharacterEncoding("utf-8");// 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系String fileName = URLEncoder.encode("橡树会员自动续费", "UTF-8");response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");ExcelWriter excelWriter = EasyExcel.write(response.getOutputStream(), RenewalSignAdminResp.class).build();WriteSheet writeSheet = EasyExcel.writerSheet("自动续费").build();req.setStartCreateTime(DateUtil.parseDate(req.getStartCreateTimeStr() + " 00:00:00", "yyyy-MM-dd HH:mm:ss"));req.setEndCreateTime(DateUtil.parseDate(req.getEndCreateTimeStr() + " 23:59:59", "yyyy-MM-dd HH:mm:ss"));int pageSize = 2000;boolean firstFlag = true;while (true) {List<RenewalSignAdminResp> data = cbsRenewalService.queryRenewalSignListForDownload(req, firstFlag, pageSize);if (CollectionUtils.isEmpty(data)) {break;}Date lastCreateTime = data.get(data.size() - 1).getCreateTime();String startId = data.get(data.size() - 1).getId();//补偿同一时间段内并发的数据 where create_time = ? and id > ? and 其他筛选条件List<RenewalSignAdminResp> otherDatas = cbsRenewalService.queryRenewalSignListByCreateTimeAndId(req, lastCreateTime, startId);data.addAll(otherDatas);excelWriter.write(data, writeSheet);req.setStartCreateTime(lastCreateTime);if (firstFlag) {firstFlag = false;}}excelWriter.finish();}

实体

package com.smy.cbs.dto.renewal;import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.annotation.format.DateTimeFormat;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.smy.cbs.easyexcel.write.RenewalStatusStringConverter;
import com.smy.cbs.easyexcel.write.VipTypeStringConverter;
import com.smy.cbs.enums.renewal.RenewalStatusEnum;
import com.smy.cbs.enums.vip.VipType;
import lombok.Getter;
import lombok.Setter;
import java.io.Serializable;
import java.util.Date;/***自动签约返回参数* @author youlu* @date 2022/9/22 10:19* @return*/
@Getter
@Setter
public class RenewalSignAdminResp implements Serializable {private static final long serialVersionUID = 472574503670404785L;//id:调用框架生成@ExcelProperty(value = "签约号", index = 0)private String id;//客户号@ExcelProperty(value = "客户号", index = 1)private String custNo;/*** 会员类型，1：橡树会员、2：自营会员* @see VipType*/@ExcelProperty(value = "会员类型", index = 2, converter = VipTypeStringConverter.class)private String vipType;//续费周期@ExcelProperty(value = "续费周期", index = 3)private Integer renewalPeriod;//签约时间@ExcelProperty(value = "签约时间", index = 4)@DateTimeFormat("yyyy-MM-dd HH:mm:ss")@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",locale = "zh",timezone="GMT+8")private Date signTime;//解约时间@ExcelProperty(value = "解约时间", index = 5)@DateTimeFormat("yyyy-MM-dd HH:mm:ss")@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",locale = "zh",timezone="GMT+8")private Date terminateTime;/*** 签约状态，1：待签约、2：签约失败、3：签约中、4：已解约* @see RenewalStatusEnum*/@ExcelProperty(value = "签约状态", index = 6, converter = RenewalStatusStringConverter.class)private String renewalStatus;//下次代扣时间@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",locale = "zh",timezone="GMT+8")@DateTimeFormat("yyyy-MM-dd HH:mm:ss")@ExcelProperty(value = "下次代扣时间", index = 7)private Date nextRenewalTime;//自动续费次数@ExcelProperty(value = "自动续费次数", index = 8)private Integer renewalNum;//投放qd@ExcelProperty(value = "投放qd", index = 9)private String qd;//创建人@ExcelProperty(value = "创建人", index = 10)private String createUser;//修改人@ExcelProperty(value = "修改人", index = 11)private String updateUser;//创建日期@ExcelProperty(value = "创建日期", index = 12)@DateTimeFormat("yyyy-MM-dd HH:mm:ss")@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",locale = "zh",timezone="GMT+8")private Date createTime;//修改日期@ExcelProperty(value = "修改日期", index = 13)@DateTimeFormat("yyyy-MM-dd HH:mm:ss")@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",locale = "zh",timezone="GMT+8")private Date updateTime;//@ExcelProperty(value = "签约商户", index = 14)private String signMerchant;}

这里要注意converter 的使用，例如：vipType在数据库中设定的是枚举值“1”,“2”,“3”,“4” 但是我们导出数据期望是其代表的含义描述，因此要转换，关注其convertToExcelData方法，转换如下：

package com.smy.cbs.easyexcel.write;import com.alibaba.excel.converters.Converter;
import com.alibaba.excel.enums.CellDataTypeEnum;
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.GlobalConfiguration;
import com.alibaba.excel.metadata.property.ExcelContentProperty;
import com.smy.cbs.enums.vip.VipType;/*** String and string converter** @author youlu*/
public class VipTypeStringConverter implements Converter<String> {@Overridepublic Class supportJavaTypeKey() {return String.class;}@Overridepublic CellDataTypeEnum supportExcelTypeKey() {return CellDataTypeEnum.STRING;}/*** 这里是读的时候会调用 不用管** @param cellData*            NotNull* @param contentProperty*            Nullable* @param globalConfiguration*            NotNull* @return*/@Overridepublic String convertToJavaData(CellData cellData, ExcelContentProperty contentProperty,GlobalConfiguration globalConfiguration) {return cellData.getStringValue();}/*** 这里是写的时候会调用 不用管** @param value*            NotNull* @param contentProperty*            Nullable* @param globalConfiguration*            NotNull* @return*/@Overridepublic CellData convertToExcelData(String value, ExcelContentProperty contentProperty,GlobalConfiguration globalConfiguration) {return new CellData(VipType.getVipTypeDescByCode(value));}
}

service|Dao层实现

 @Overridepublic List<RenewalSignAdminResp> queryRenewalSignListForDownload(RenewalSignAdminReq req, boolean firstFlag, int pageSize) {return cbsRenewalSignInnerService.queryRenewalSignListForDownload(req, firstFlag, pageSize);}@Overridepublic List<RenewalSignAdminResp> queryRenewalSignListByCreateTimeAndId(RenewalSignAdminReq req, Date createTime, String startId) {return cbsRenewalSignInnerService.queryRenewalSignListByCreateTimeAndId(req,createTime, startId);}

sql层查询

<select id="queryRenewalSignListForDownload" resultMap="signAdminMap">select<include refid="Base_Column_List" />from t_renewal_sign<where><choose><when test="firstFlag">and create_time &gt;= #{req.startCreateTime}</when><otherwise>and create_time &gt; #{req.startCreateTime}</otherwise></choose>and create_time &lt;= #{req.endCreateTime}and renewal_status = #{req.renewalStatus}<if test="req.custNo != null and req.custNo != ''">and cust_no = #{req.custNo}</if><if test="req.id != null and req.id != ''">and id = #{req.id}</if><if test="req.vipType != null and req.vipType != ''">and vip_type = #{req.vipType}</if></where>order by create_time , idlimit #{pageSize}</select>

firstFlag 用于区分是否是第一次查询
order by create_time , id 的排序可以用于解决慢sql问题。
这个查询会存在漏数据的问题，因此引进下面这条sql专门查询在相同时间点内生成的数据

 <select id="queryRenewalSignListByCreateTimeAndId" resultMap="signAdminMap">select<include refid="Base_Column_List" />from t_renewal_sign<where>and create_time = #{createTime}and id &gt; #{startId}and renewal_status = #{req.renewalStatus}<if test="req.custNo != null and req.custNo != ''">and cust_no = #{req.custNo}</if><if test="req.id != null and req.id != ''">and id = #{req.id}</if><if test="req.vipType != null and req.vipType != ''">and vip_type = #{req.vipType}</if></where>