SpringBoot2.x使用POI实现导入数据到Excel_Java

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。

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