一、controller层

@ApiOperation(value = "明细查询导出")
@PostMapping(value = "/SummaryDetailExport")
public void summaryDetailExport(@RequestBody SearchDTO dto, HttpServletResponse response) throws IOException {
    reportService.deptPackagingSummaryDetailExport(dto, response);
}

二、serviceimpl

@Override
    public void deptPackagingSummaryDetailExport(SearchDTO dto, HttpServletResponse response) throws IOException {
        // 这里必须指定需要头，table 会继承sheet的配置，sheet配置了不需要，table 默认也是不需要
        List<DeptSummaryReq> exportVos = configPackageTaskMapper.DeptPackagingSummary(dto);
        DecimalFormat df = new DecimalFormat("#.00");
        response.setContentType("application/vnd.ms-excel;charset=utf-8");
        response.setCharacterEncoding("utf-8");
        response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode("科室打包明细查询" + ".xlsx", "UTF-8"));
        ServletOutputStream outputStream = response.getOutputStream();
        ExcelWriter excelWriter = EasyExcel.write(outputStream).build();
        //在根据科室id去查询有哪些包，以及价格
        for (int i = 0; i < exportVos.size(); i++) {
            dto.setDeptId(exportVos.get(i).getDeptId());
            List<DeptSummaryReq> detail = configPackageTaskMapper.queryDeptPackagingDetailBydeptId(dto);
            for (DeptSummaryReq regDetail : detail) {
                if (regDetail.getPrice() == null) {
                    regDetail.setAmount(0.00);
                    regDetail.setPrice(0.00);
                } else {
                    regDetail.setAmount(BigDecimal.valueOf(regDetail.getPrice()).multiply(BigDecimal.valueOf(regDetail.getPackageCount())).doubleValue());
                }
            }

            DeptSummaryReq regDetail1 = new DeptSummaryReq();
            regDetail1.setPackageCode(dto.getStartTime() + "    " + dto.getEndTime() + "    打印时间：" + DateUtil.now());
            DeptSummaryReq regDetail2 = new DeptSummaryReq();
            if (dto.getPackageType() == null) {
                List<String> typeName = recoverPackagesMapper.queryPackageType();
                regDetail2.setPackageCode("包类型：" + String.join("，", typeName));
            } else {
                regDetail2.setPackageCode("包类型：" + String.join("，", dto.getPackageName()));
            }
            DeptSummaryReq regDetail = new DeptSummaryReq();
            regDetail.setPackageCode("科室数量合计:    " + detail.stream().mapToInt(DeptSummaryReq::getPackageCount).sum()
                    + "       科室金额合计:   ¥" + Double.valueOf(df.format(detail.stream().mapToDouble(DeptSummaryReq::getAmount).sum())));
            detail.add(regDetail);
            detail.add(regDetail1);
            detail.add(regDetail2);
            //创建合并策略
            //这里我们上面手动给我们的list添加了3条数据
            //这3天数据是需要合并单元格显示的，所以我们这里需要new 3个OnceAbsoluteMergeStrategy
            // 前面2个数字代表的是行，后面两个代表从那一列开始，到那一列结束
            //比如我们要展示五个字段，那么就是0,4；从0开始到4就一共5列
            OnceAbsoluteMergeStrategy onceAbsoluteMergeStrategy = new OnceAbsoluteMergeStrategy(detail.size() + 1, detail.size() + 1, 0, 4);
            OnceAbsoluteMergeStrategy onceAbsoluteMergeStrategy1 = new OnceAbsoluteMergeStrategy(detail.size(), detail.size(), 0, 4);
            OnceAbsoluteMergeStrategy onceAbsoluteMergeStrategy2 = new OnceAbsoluteMergeStrategy(detail.size() - 1, detail.size() - 1, 0, 4);

            //创建一个sheet
            WriteSheet writeSheet = EasyExcel.writerSheet(i, exportVos.get(i).getDeptName())
                    .head(DeptPackagingSummaryDetailExcel.class)
                    //.registerWriteHandler(new LongestMatchColumnWidthStyleStrategy())
                    .registerWriteHandler(ExcelUtil.writeCenterStyle())
                    .registerWriteHandler(onceAbsoluteMergeStrategy)
                    .registerWriteHandler(onceAbsoluteMergeStrategy1)
                    .registerWriteHandler(onceAbsoluteMergeStrategy2)
                    .build();

            //将sheet写入excelwriter
            excelWriter.write(detail, writeSheet);
        }
        if (excelWriter != null) {
            excelWriter.finish();
        }
    }

三、entity

DeptSummaryReq

import com.alibaba.excel.annotation.ExcelIgnore;
import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.annotation.write.style.ColumnWidth;
import com.alibaba.excel.annotation.write.style.ContentStyle;
import com.alibaba.excel.annotation.write.style.HeadRowHeight;
import com.alibaba.excel.annotation.write.style.HeadStyle;
import com.alibaba.excel.enums.poi.HorizontalAlignmentEnum;
import com.cloud.common.core.annotation.ExcelParam;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.*;

import java.math.BigDecimal;
import java.util.Date;
import java.util.List;

@Data
@ColumnWidth(25)//设置列宽
@HeadRowHeight(20)//设置行高
@EqualsAndHashCode
@HeadStyle(horizontalAlignment = HorizontalAlignmentEnum.CENTER)//表头样式
@ContentStyle(horizontalAlignment = HorizontalAlignmentEnum.CENTER)//内容样式
@ApiModel(value="DeptSummaryReq", description="导出出参")
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class DeptSummaryReq {
    private static final long serialVersionUID=1L;

    @ApiModelProperty(value = "包编码")
    @ExcelProperty({"明细报表", "包编码"})
    private String packageCode;

    @ApiModelProperty(value = "包名称")
    @ExcelProperty({"明细报表", "包名称"})
    private String packageName;

    @ApiModelProperty(name = "数量")
    @ExcelProperty({"明细报表", "数量"})
    private int packageCount;

    @ApiModelProperty(name = "单价")
    @ExcelProperty({"明细报表", "单价"})
    private Double price;

    @ApiModelProperty(name = "金额")
    @ExcelProperty({"明细报表", "金额"})
    private Double  amount;

    @ApiModelProperty(name = "科室id")
    @ExcelIgnore
    private Integer deptId;

    @ApiModelProperty(name = "科室名称")
    @ExcelIgnore
    private String deptName;

}

四、效果