一篇完整的Java实现excel导入导出（包含前端页面）
1.开发环境
后台用springboot
前台纯html+js
2.工程导入pom
<dependency>
<groupId>org.apache.poigroupId>
<artifactId>poiartifactId>
<version>3.16version>
dependency>
<dependency>
<groupId>org.apache.poigroupId>
<artifactId>poi-ooxmlartifactId>
<version>3.16version>
dependency>
3.写后端工具类
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.net.URLEncoder;
import java.text.SimpleDateFormat;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.*;
/**
* excel工具类
*/
public class ExcelUtil {
/**
* 将Excel内容转换list
* @param file
* @param name
* @return
* @throws Exception
*/
public static List<Map<String, Object>> excelToList(MultipartFile file, String name) throws Exception {
Workbook workbook = WorkbookFactory.create(file.getInputStream());
Sheet sheet = workbook.getSheet(name);
//行数
int num = sheet.getLastRowNum();
//列数
int col = sheet.getRow(0).getLastCellNum();
List<Map<String, Object>> list = new ArrayList<>();
String[] colName = new String[col];
//获取列名
Row row = sheet.getRow(0);
for (int i = 0; i < col; i++) {
String[] s = row.getCell(i).getStringCellValue().split("-");
colName[i] = s[0];
}
//将一行中每列数据放入一个map中,然后把map放入list
for (int i = 1; i <= num; i++) {
Map<String, Object> map = new HashMap<>();
Row row1 = sheet.getRow(i);
if (row1 != null) {
for (int j = 0; j < col; j++) {
Cell cell = row1.getCell(j);
if (cell != null) {
cell.setCellType(Cell.CELL_TYPE_STRING);
map.put(colName[j], cell.getStringCellValue());
}
}
}
list.add(map);
}
return list;
}
/**
* 导出集合到excel
* @param response
* @param name
* @param list
*/
public static void exportToExcel(HttpServletResponse response, String name, List<LinkedHashMap<String, Object>> list) {
try {
//文件名称
String fileName = name + ".xls";
HSSFWorkbook hssfWorkbook = new HSSFWorkbook();
HSSFSheet hssfSheet = hssfWorkbook.createSheet(name);
int rowNum = 0;
//新建行
HSSFRow hssfRow = hssfSheet.createRow(rowNum++);
//列
int j = 0;
if (list.size() > 0) {
for (String i : list.get(0).keySet()) {
//新建第一行
hssfRow.createCell(j++).setCellValue(i);
}
//将数据放入表中
for (int i = 0; i < list.size(); i++) {
//新建一行
HSSFRow row = hssfSheet.createRow(rowNum++);
Map map = list.get(i);
System.out.println(map);
j = 0;
for (Object obj : map.values()) {
if (obj != null) {
row.createCell(j++).setCellValue(obj.toString());
} else {
row.createCell(j++);
}
}
}
}
// 告诉浏览器用什么软件可以打开此文件
response.setHeader("content-Type", "application/vnd.ms-excel");
// 下载文件的默认名称
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "utf-8"));
hssfWorkbook.write(response.getOutputStream());
} catch (Exception e) {
e.printStackTrace();
}
}
/***
* 解析Excel日期格式
* @param strDate
* @return
*/
public static String ExcelDoubleToDate(String strDate) {
if (strDate.length() == 5) {
try {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date tDate = DoubleToDate(Double.parseDouble(strDate));
return sdf.format(tDate);
} catch (Exception e) {
e.printStackTrace();
return strDate;
}
}
return strDate;
}
/**
* 解析Excel日期格式
* @param dVal
* @return
*/
public static Date DoubleToDate(Double dVal) {
Date tDate = new Date();
//系统时区偏移 1900/1/1 到 1970/1/1 的 25569 天
long localOffset = tDate.getTimezoneOffset() * 60000;
tDate.setTime((long) ((dVal - 25569) * 24 * 3600 * 1000 + localOffset));
return tDate;
}
}
直接拿去贴
4.导出查询结果到excel
1.写后端controller
/**
* 导出excel
* @return
*/
@RequestMapping("/exportMonitor")
@ResponseBody
public void exportMonitor(String monitorName,String monitorState,String monitorOccupyState,String monitorSwitchState ,String significant, HttpServletResponse response){
Map<String,Object> param=new HashMap<String, Object>(8);
param.put("monitorName",monitorName);
param.put("monitorState",monitorState);
param.put("monitorOccupyState",monitorOccupyState);
param.put("monitorSwitchState",monitorSwitchState);
param.put("significant",significant);
List<LinkedHashMap<String,Object>> database=monitorService.getAllMonitorLinkedHashMap(param);
ExcelUtil.exportToExcel(response,"monitor",database);
//return ResultObj.returnObj(DatabaseUtil.returnDatabaseNoResult(true,"导出成功"));
}
注意，这里要用get形式，因为前台的地址是拼接起来的，这点很重要，看下面就知道了
2.写前端js
Monitor.export=function(){
let export1 = document.getElementById('export');
//字符串拼接，不然传的就是'undefined'，真的是这个字符串传过去
let params ='';
if($("#monitorName").val()){
params+='&monitorName';
}
if($("#monitorState").val()){
params+='&monitorState';
}
if($("#monitorOccupyState").val()){
params+='&monitorOccupyState';
}
if($("#monitorSwitchState").val()){
params+='&monitorSwitchState';
}
if($("#significant").val()){
params+='&significant';
}
//截取前面的&
export1.setAttribute('href',"/monitor/exportMonitor?"+params.substring(1,params.length));
}
这个export是关键字，不能用，懒得改名了，加了个1
3.写前端html
<a id="export" >
<button type="button" class="btn btn-primary " onclick="Monitor.export()" id="importMonitor">
<i class="fa fa-search">i> 导出
button>
a>
导出按钮，用a标签括起来，这里利用js的冒泡事件，js点击这个button，然后调用上面js的函数，这个函数改变这个a标签t的地址，函数执行完成之后，向上冒泡，相当于点击了a标签，a标签跳转后台页面。
4.总结
之前用过ajax执行，然后他返回的response里有一个xls的文件，这里已经改好了，我的就不回退回去了，借用别的老哥两张图
出自https://blog.csdn.net/jinchunzhao123/article/details/88626077
我的response跟他类似，这是我的后台
只有展示，浏览器没有自动下载
之后将这个地址放在a标签里，使用herf跳转就完事了
5.导入excel到数据库
1.写后端controller
/**
* 导入excel
* @param file
* @return
*/
@RequestMapping("/importMonitor")
@ResponseBody
public Object importMonitor(@RequestParam MultipartFile file){
Map<String,Object> database=monitorService.importMonitor(file);
return ResultObj.returnObj(database);
}
2.写service
@Override
public Map<String, Object> importMonitor(MultipartFile file) {
Map<String,Object> param=new HashMap<String, Object>(8);
try {
List<Map<String,Object>> importList= ExcelUtil.excelToList(file,excelSelect);
for (Map<String,Object> importMap: importList) {
String id= OddNumbersUtil.getNumber("monitor");
param.put("id",id);
param.put("monitorName",importMap.get("monitor_name"));
param.put("monitorNumebr",importMap.get("monitor_numebr"));
param.put("ip",importMap.get("ip"));
param.put("port",importMap.get("port"));
param.put("monitorState",1);
param.put("monitorOccupyState",1);
param.put("createTime",new Date());
param.put("createPerson",ShiroKit.getUser().name);
//param.put("updateTime",importMap.get("update_time"));
//param.put("updatePerson",importMap.get("update_person"));
param.put("imgUrl",importMap.get("img_url"));
param.put("contacts",importMap.get("contacts"));
param.put("contactNumber",importMap.get("contact_number"));
param.put("installDate",ExcelUtil.ExcelDoubleToDate(String.valueOf(importMap.get("install_date"))));
param.put("periodOfValidity",ExcelUtil.ExcelDoubleToDate(String.valueOf(importMap.get("period_of_validity"))));
param.put("expirationDate",ExcelUtil.ExcelDoubleToDate(String.valueOf(importMap.get("expiration_date"))));
param.put("deviceAddress",importMap.get("device_address"));
param.put("monitorSwitchState",1);
param.put("deviceType",importMap.get("device_type"));
param.put("modelType",importMap.get("model_type"));
param.put("significant",importMap.get("significant"));
param.put("locational",importMap.get("locational"));
param.put("manufacturersId",importMap.get("manufacturers_id"));
param.put("deviceCoding",importMap.get("device_coding"));
param.put("subordinateSubsystem",importMap.get("subordinate_subsystem"));
monitorMapper.addMonitor(param);
}
return DatabaseUtil.returnDatabaseNoResult(true,"导入成功");
} catch (Exception e) {
e.printStackTrace();
return DatabaseUtil.returnDatabaseNoResult(true,"导入失败");
}
}
这里略过接口，直接看实现类，里面有的地方用了ExcelUtil.ExcelDoubleToDate()函数，是因为excel读取的日期是一个数字，用这个函数可以转为规定的日期格式，这个函数详见上面的工具类
2.写前端js
方式1
layui.use('upload', function(){
var upload = layui.upload;
//执行实例
var uploadInst = upload.render({
elem: '#importMonitor' //绑定元素
,url: 'monitor/importMonitor' //上传接口
,accept: 'file'
,exts: 'xls|xlsx|xlsm|xlt|xltx|xltm'
,done: function(res){
if(res.success){
layer.msg('导入成功');
stockRecord.table.refresh();
}else{
layer.msg(res.message());
}
//上传完毕回调
}
,error: function(){
//请求异常回调
}
});
});
这是layui的上传文件，今天向同事学的，推荐使用这个，比较方便
3.写前端html
<#button name="导入excel" icon="fa" id="importMonitor"/>
前台只要有一个元素承接就行了