导出excel

依赖

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>2.2.6</version>
        </dependency>

package cn.visight;
import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.write.builder.ExcelWriterBuilder;
import java.util.*;
import java.util.stream.Collectors;
public class ExcelTest {
    public static void main(String args[]) {
        // 文件输出位置
        String fileName = "D:\\visi\\workspace\\统计.xlsx";
        Set<String> allDateList = new HashSet<>();
        Set<String> allOutletsNameList = new HashSet();
        List<XData> dataList = getDataList();
        dataList.forEach(r -> {
            // 1.获取所有的日期List
            allDateList.add(r.getDate());
            // 2.获取所有的名字Map
            allOutletsNameList.add(r.getOutletsName());
        });
        // 3.获取所有的日期对应的数据Map
        Map<String, List<XData>> date2XDataMap = dataList.stream().collect(Collectors.groupingBy(XData::getDate));
        ExcelWriterBuilder builder = EasyExcel.write(fileName);
        List<List<String>> headData = getExcelHeadData(allOutletsNameList);
        List<List<Object>> excelDataList = getExcelDataList(allDateList, allOutletsNameList, date2XDataMap);
        builder.head(headData).sheet("统计数据").doWrite(excelDataList);
    }
    private static List<List<Object>> getExcelDataList(Set<String> allDateList, Set<String> allOutletsNameList, Map<String, List<XData>> date2XDataMap) {
        List<List<Object>> excelDatalist = new ArrayList<>();
        //网点小计
        Map<String, Subtotal> outletsName2Subtotal = new HashMap<>();
        //过包总计
        Integer totalNumCount = 0;
        //违禁品总计
        Integer dangerNumCount = 0;
        // 2.获取excel表数据
        for (String currDate : allDateList) {
            List<Object> rowData = new ArrayList<>();
            rowData.add(currDate);
            for (String outletsName : allOutletsNameList) {
                //初始化小计数据
                Subtotal subtotal = outletsName2Subtotal.get(outletsName);
                if (subtotal == null) {
                    outletsName2Subtotal.put(outletsName, new Subtotal(0, 0));
                }
                List<XData> numList = date2XDataMap.get(currDate);
                boolean isNotExist = false;
                for (XData xData : numList) {
                    if (outletsName.equals(xData.getOutletsName())) {
                        Integer dangerNum = xData.getDangerNum() == null ? 0 : xData.getDangerNum();
                        Integer totalNum = xData.getTotalNum() == null ? 0 : xData.getTotalNum();
                        rowData.add(totalNum);
                        rowData.add(dangerNum);
                        isNotExist = false;
                        //统计小计数量
                        Subtotal currSubtotal = outletsName2Subtotal.get(outletsName);
                        currSubtotal.setSubTotalNum(currSubtotal.getSubTotalNum() + totalNum);
                        currSubtotal.setSubDangerNum(currSubtotal.getSubDangerNum() + dangerNum);
                        //统计总计数量
                        totalNumCount += totalNum;
                        dangerNumCount += dangerNum;
                        break;
                    } else {
                        isNotExist = true;
                    }
                }
                //没有该网点的数量，则给默认值0
                if (isNotExist) {
                    rowData.add(0);
                    rowData.add(0);
                }
            }
            excelDatalist.add(rowData);
        }
        // 3.存入小计
        List<Object> rowSubtotalData = new ArrayList<>();
        rowSubtotalData.add("小计");
        allOutletsNameList.forEach(outletsName -> {
            Subtotal subtotal = outletsName2Subtotal.get(outletsName);
            Integer subTotalNum = subtotal.getSubTotalNum();
            Integer subDangerNum = subtotal.getSubDangerNum();
            rowSubtotalData.add(subTotalNum);
            rowSubtotalData.add(subDangerNum);
        });
        excelDatalist.add(rowSubtotalData);
        // 4.存入总计
        List<Object> rowTotalCountData = new ArrayList<>();
        rowTotalCountData.add("过包总计");
        rowTotalCountData.add(totalNumCount);
        excelDatalist.add(rowTotalCountData);
        List<Object> rowDangerCountData = new ArrayList<>();
        rowDangerCountData.add("违禁品数总计");
        rowDangerCountData.add(dangerNumCount);
        excelDatalist.add(rowDangerCountData);
        return excelDatalist;
    }
    private static List<List<String>> getExcelHeadData(Set<String> allOutletsNameList) {
        List<List<String>> list = new ArrayList<>();
        // 1.获取excel表头
        List<String> head0 = new ArrayList<>();
        head0.add("网点\n数目\n日期");
        list.add(head0);
        List<String> childrenHeadTitleList = new ArrayList<>();
        childrenHeadTitleList.add("总数");
        childrenHeadTitleList.add("违禁品数");
        allOutletsNameList.forEach(outletsName -> {
            childrenHeadTitleList.forEach(childName -> {
                List<String> head = new ArrayList<>();
                head.add(outletsName);
                head.add(childName);
                list.add(head);
            });
        });
        return list;
    }
    private static List<XData> getDataList() {
        List<XData> list = new ArrayList<>();
        list.add(new XData("2021-08-19", 239, 0, "韵达"));
        list.add(new XData("2021-08-19", 6, 8, "申通"));
        list.add(new XData("2021-08-20", 5, 0, "德邦"));
        list.add(new XData("2021-08-20", 623, 0, "韵达"));
        list.add(new XData("2021-08-20", 74, 2, "长途汽车站"));
        list.add(new XData("2021-08-20", 2, 3, "申通"));
        return list;
    }
}
class XData {
    private String date;
    private String outletsName;
    private Integer totalNum;
    private Integer dangerNum;
    public XData(String date, Integer totalNum, Integer dangerNum, String outletsName) {
        this.date = date;
        this.outletsName = outletsName;
        this.totalNum = totalNum;
        this.dangerNum = dangerNum;
    }
    public String getDate() {
        return date;
    }
    public void setDate(String date) {
        this.date = date;
    }
    public String getOutletsName() {
        return outletsName;
    }
    public void setOutletsName(String outletsName) {
        this.outletsName = outletsName;
    }
    public Integer getTotalNum() {
        return totalNum;
    }
    public void setTotalNum(Integer totalNum) {
        this.totalNum = totalNum;
    }
    public Integer getDangerNum() {
        return dangerNum;
    }
    public void setDangerNum(Integer dangerNum) {
        this.dangerNum = dangerNum;
    }
}
class Subtotal {
    private Integer subTotalNum;
    private Integer subDangerNum;
    public Integer getSubTotalNum() {
        return subTotalNum;
    }
    public void setSubTotalNum(Integer subTotalNum) {
        this.subTotalNum = subTotalNum;
    }
    public Integer getSubDangerNum() {
        return subDangerNum;
    }
    public void setSubDangerNum(Integer subDangerNum) {
        this.subDangerNum = subDangerNum;
    }
    public Subtotal(Integer subTotalNum, Integer subDangerNum) {
        this.subTotalNum = subTotalNum;
        this.subDangerNum = subDangerNum;
    }
}