Java(SpringBoot2.x)使用POI导入数据到Excel_poi4.1.2 和 springboot2.x

一、前言

最近做一个推送服务将系统某些报表，通过邮件附件的形式推送给指定的人，首先我们需要在服务端生成报表的excel文档。生成excel文档采用的是POI的方式。

二、pom引入相应的jar包

引入三个poi相关的jar包

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>4.1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>4.1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml-schemas</artifactId>
            <version>4.1.2</version>
        </dependency>

注意：这三个jar包的版本号一定要保持一致。否则的话会引起异常，无法创建XSSFWorkbook

三、导出方法封装类

import lombok.extern.slf4j.Slf4j;
import org.apache.http.client.utils.DateUtils;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.Timestamp;
import java.util.*;
 
/**
 * POI导出Excel封装
 * @author lenny
 * @date 20210715
 */
@Slf4j
public class ExcelUtil {
    /**
     * @param fileName excel文件名
     * @param headMap  表头map
     * @param dataList 表格数据
     */
    public static String exportExcel(String fileName,Map<String, String> headMap, List<Map<String, Object>> dataList) {
        String fullPath="";
        Workbook workbook = exportXlsx(fileName, headMap, dataList);
        FileOutputStream outputStream=null;
        try {
            //将生成的excel存储在系统根目录下excel文件夹中
            String path=CommonUtil.getRunningDirectory()+"\\excel\\";
            fullPath=path+fileName;
            outputStream = new FileOutputStream(path+fileName);
            workbook.write(outputStream);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        //返回文件所在的目录
        return fullPath;
    }
 
    /**
     * 导出数据
     *
     * @param headMap 表头map
     * @param dataList 导出的数据
     */
    public static Workbook exportXlsx(String sheetName, Map<String, String> headMap, List<Map<String, Object>> dataList) {
        try {
            XSSFWorkbook workbook = new XSSFWorkbook();
            Sheet sheet = workbook.createSheet(sheetName);
            //初始化行列索引
            int rowIndex = 0, columnIndex = 0;
            Set<String> keys = headMap.keySet();
            //表头
            Row row = sheet.createRow(rowIndex++);
            for (String key : keys) {
                Cell cell = row.createCell(columnIndex++);
                cell.setCellValue(headMap.get(key));
            }
            //内容
            if (dataList != null && !dataList.isEmpty()) {
                for (Map<String, Object> map : dataList) {
                    row = sheet.createRow(rowIndex++);
                    columnIndex = 0;
                    for (String key : keys) {
                        Cell cell = row.createCell(columnIndex++);
                        setCellValue(cell, map.get(key));
                    }
                }
            }
            return workbook;
        }catch (Exception e){
            log.error(e.toString());
            return null;
        }
    }
 
    /**
     * 填充单元格内容
     * @param cell
     * @param obj
     */
    private static void setCellValue(Cell cell, Object obj) {
        if (obj == null) {
            return;
        }
        if (obj instanceof String) {
            cell.setCellValue((String) obj);
        } else if (obj instanceof Date) {
            Date date = (Date) obj;
            if (date != null) {
                cell.setCellValue(DateUtils.formatDate(date));
            }
        } else if (obj instanceof Calendar) {
            Calendar calendar = (Calendar) obj;
            if (calendar != null) {
                cell.setCellValue(DateUtils.formatDate(calendar.getTime()));
            }
        } else if (obj instanceof Timestamp) {
            Timestamp timestamp = (Timestamp) obj;
            if (timestamp != null) {
                cell.setCellValue(DateUtils.formatDate(new Date(timestamp.getTime())));
            }
        } else if (obj instanceof Double) {
            cell.setCellValue((Double) obj);
        } else {
            cell.setCellValue(obj.toString());
        }
    }
}

其中使用到了封装的获取系统根目录的方法，方法实现如下：

    /**
     * 得到程序运行的根目录
     * @return
     */
    public static String getRunningDirectory()
    {
        return System.getProperty("user.dir");
    }

四、调用方法执行生成excel操作

    /**
     * 导出Adas报警
     * @param reportAdasList
     * @param language
     * @param timeDiff
     * @return
     */
    public static String exportAdasReport(List<ReportAdasList> reportAdasList, int language, int timeDiff) {
        //表头
        Map<String, String> headNameMap = new LinkedHashMap<String, String>();
        headNameMap.put("agentName", getHeadName("agentName",language));
        headNameMap.put("vehicleName", getHeadName("vehicleName",language));
        headNameMap.put("assetID", getHeadName("assetID",language));
        headNameMap.put("alarmType", getHeadName("alarmType",language));
        headNameMap.put("alarmLevel", getHeadName("alarmLevel",language));
        headNameMap.put("startTime", getHeadName("startTime",language));
        headNameMap.put("endTime", getHeadName("endTime",language));
        headNameMap.put("driverName", getHeadName("driverName",language));
        headNameMap.put("startAddress", getHeadName("startAddress",language));
        headNameMap.put("endAddress", getHeadName("endAddress",language));
        headNameMap.put("processStatus", getHeadName("processStatus",language));
        headNameMap.put("processContext", getHeadName("processContext",language));
        headNameMap.put("processTime", getHeadName("processTime",language));
        //表格数据
        List<Map<String, Object>> dataList = new ArrayList<Map<String, Object>>();
        for(ReportAdasList item : reportAdasList){
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("agentName", item.getAgentName());
            map.put("vehicleName", item.getVehicleName());
            map.put("assetID", item.getAssetID());
            map.put("alarmType", language==1?item.getCnName():item.getEnName());
            map.put("alarmLevel", getAlarmLevel(item.getAlarmLevel(),language));
            map.put("startTime", CommonUtil.getLocalTime(item.getStartTime(),timeDiff));
            map.put("endTime", CommonUtil.getLocalTime(item.getEndTime(),timeDiff));
            map.put("driverName", item.getDriverName());
            map.put("startAddress", CommonUtil.geoCoding(String.valueOf(item.getStartLatitude()),String.valueOf(item.getStartLongitude()),language));
            map.put("endAddress", CommonUtil.geoCoding(String.valueOf(item.getEndLatitude()),String.valueOf(item.getEndLongitude()),language));
            map.put("processStatus", getProcessStatus(item.getProcessStatus(),language));
            map.put("processContext", item.getProcessContext());
            map.put("processTime", CommonUtil.getLocalTime(item.getProcessTime(),timeDiff));
            dataList.add(map);
        }
        String fileName = "";
        if(language==1) {
            fileName= CommonConstants.CN_REPORT_ADAS;
        }else {
            fileName=CommonConstants.EN_REPORT_ADAS;
        }
        fileName=fileName+".xlsx";
        String fullPath = ExcelUtil.exportExcel(fileName,headNameMap,dataList);
        return fullPath;
    }

这里大家可以根据自己的系统自行调整，最后封装成headMap（表头字段）与List<Map<String, Object>>（数据列表）即可。