这篇文章主要介绍“Java如何利用POI实现导入导出Excel表格”的相关知识，小编通过实际案例向大家展示操作过程，操作方法简单快捷，实用性强，希望这篇“Java如何利用POI实现导入导出Excel表格”文章能帮助大家解决问题。
一、Java利用POI实现导入导出Excel表格demo
1.引入依赖
<dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>4.1.2</version> </dependency>
2.导入demo
2.1 controller层
/**
* Excel导入
*/
@PostMapping("/import")
public Result userImport2(@RequestParam("file") MultipartFile file) throws Exception{
Result result=userService.userImportExcel(file);
return result;
}2.2 service实现类层
public Result userImportExcel(MultipartFile file){
try {
InputStream inputStream = file.getInputStream();
XSSFWorkbook sheets = new XSSFWorkbook(inputStream);
//获取表单sheet 第一个
XSSFSheet sheetAt = sheets.getSheetAt(0);
//获取第一行
int firstRowNum = sheetAt.getFirstRowNum();
//最后一行
int lastRowNum = sheetAt.getLastRowNum();
//存入数据集合
List<User> users=new ArrayList<>();
//遍历数据
for(int i=firstRowNum+1;i<lastRowNum+1;i++){
XSSFRow row = sheetAt.getRow(i);
if(row!=null){
/* //获取第一行的第一列
int firstCellNum = row.getFirstCellNum();
//获取第一行的最后列
short lastCellNum = row.getLastCellNum();
for (int j=firstCellNum;j<lastCellNum+1;j++){
//放入集合中需要可以用这种方法
String cellValue = getValue(row.getCell(firstCellNum));
}*/
//这里我就直接赋值
User user = new User();
user.setUname(row.getCell(0).getStringCellValue());
user.setUpassword(row.getCell(1).getStringCellValue());
user.setUsex(row.getCell(2).getStringCellValue());
user.setRole(row.getCell(3).getStringCellValue());
user.setUlove((int) row.getCell(4).getNumericCellValue());
user.setUphoto(row.getCell(5).getStringCellValue());
user.setUaddress(row.getCell(6).getStringCellValue());
users.add(user);
}
}
//保存数据
saveBatch(users);
return Result.success();
}catch (Exception e){
e.printStackTrace();
log.info("error:{}",e);
}
return Result.error("300","导入失败");
}
/**
* 判断值的类型
*/
public String getValue(HSSFCell cell) {
if(cell==null){
return "";
}
String cellValue= "";
try {
DecimalFormat df=new DecimalFormat("0.00");
if(cell.getCellType()== CellType.NUMERIC){
//日期时间转换
if(HSSFDateUtil.isCellDateFormatted(cell)){
cellValue=DateFormatUtils.format(cell.getDateCellValue(),"yyyy-MM-dd");
}else{
NumberFormat instance = NumberFormat.getInstance();
cellValue=instance.format(cell.getNumericCellValue()).replace(",","");
}
}else if(cell.getCellType() == CellType.STRING){
//字符串
cellValue=cell.getStringCellValue();
}else if(cell.getCellType() == CellType.BOOLEAN){
//Boolean
cellValue= String.valueOf(cell.getBooleanCellValue());
}else if(cell.getCellType() == CellType.ERROR){
//错误
}else if(cell.getCellType() == CellType.FORMULA){
//转换公式 保留两位
cellValue=df.format(cell.getNumericCellValue());
}else{
cellValue=null;
}
} catch (Exception e) {
e.printStackTrace();
cellValue="-1";
}
return cellValue;
}3.导出demo
3.1 controller层
/**
* 导出
* @param response
* @return
* @throws Exception
*/
@GetMapping("/export")
public Result userExport2(HttpServletResponse response) throws Exception{
Result result=userService.userExportExcel(response);
return result;
}3.2 service实现类
public Result userExportExcel(HttpServletResponse response) {
try {
//创建excel
XSSFWorkbook sheets = new XSSFWorkbook();
//创建行
XSSFSheet sheet = sheets.createSheet("用户信息");
//格式设置
XSSFCellStyle cellStyle = sheets.createCellStyle();
//横向居中
cellStyle.setAlignment(HorizontalAlignment.CENTER);
//创建单元格第一列
XSSFRow row = sheet.createRow(0);
//表头
this.titleExcel(row,cellStyle);
//查询全部的用户数据 mybatis-plus
List<User> list = list();
//遍历设置值
for(int i=0;i<list.size();i++){
XSSFRow rows = sheet.createRow(i+1);
User user=list.get(i);
//表格里赋值
this.titleExcelValue(user,rows,cellStyle);
}
//设置浏览器响应格式
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
String filName= URLEncoder.encode("用户信息","UTF-8");
response.setHeader("Content-Disposition","attachment;filename="+filName+".xls");
ServletOutputStream outputStream=response.getOutputStream();
sheets.write(outputStream);
outputStream.close();
sheets.close();
return Result.success();
}catch (Exception e){
e.printStackTrace();
log.info("error:{}",e);
}
return Result.error("300","导出失败");
}
/**
*表格里赋值
**/
public void titleExcelValue(User user, XSSFRow row,XSSFCellStyle cellStyle) {
XSSFCell cellId = row.createCell(0);
cellId.setCellValue(user.getUid());
cellId.setCellStyle(cellStyle);
XSSFCell cellUserName = row.createCell(1);
cellUserName.setCellValue(user.getUname());
cellUserName.setCellStyle(cellStyle);
XSSFCell cellPassword = row.createCell(2);
cellPassword.setCellValue(user.getUpassword());
cellPassword.setCellStyle(cellStyle);
XSSFCell cellSex = row.createCell(3);
cellSex.setCellValue(user.getUsex());
cellSex.setCellStyle(cellStyle);
XSSFCell cellRole = row.createCell(4);
cellRole.setCellValue(user.getRole());
cellRole.setCellStyle(cellStyle);
XSSFCell cellLoveValue = row.createCell(5);
cellLoveValue.setCellValue(user.getRole());
cellLoveValue.setCellStyle(cellStyle);
XSSFCell cellPhone = row.createCell(6);
cellPhone.setCellValue(user.getUphoto());
cellPhone.setCellStyle(cellStyle);
XSSFCell cellAddress = row.createCell(7);
cellAddress.setCellValue(user.getUaddress());
cellAddress.setCellStyle(cellStyle);
}
/**
表头
**/
public void titleExcel(XSSFRow row,XSSFCellStyle cellStyle){
XSSFCell cellId = row.createCell(0);
cellId.setCellValue("用户ID");
cellId.setCellStyle(cellStyle);
XSSFCell cellUserName = row.createCell(1);
cellUserName.setCellValue("用户名");
cellUserName.setCellStyle(cellStyle);
XSSFCell cellPassword = row.createCell(2);
cellPassword.setCellValue("密码");
cellPassword.setCellStyle(cellStyle);
XSSFCell cellSex = row.createCell(3);
cellSex.setCellValue("性别");
cellSex.setCellStyle(cellStyle);
XSSFCell cellRole = row.createCell(4);
cellRole.setCellValue("角色");
cellRole.setCellStyle(cellStyle);
XSSFCell cellLoveValue = row.createCell(5);
cellLoveValue.setCellValue("爱心值");
cellLoveValue.setCellStyle(cellStyle);
XSSFCell cellPhone = row.createCell(6);
cellPhone.setCellValue("电话号码");
cellPhone.setCellStyle(cellStyle);
XSSFCell cellAddress = row.createCell(7);
cellAddress.setCellValue("地址");
cellAddress.setCellStyle(cellStyle);
}二、Hutool工具类封装方法导出导入Excel
1.引入依赖
把poi封装到工具类方法里面
<!-- hutool --> <dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-all</artifactId> <version>5.7.20</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>4.1.2</version> </dependency>
2.导入demo
/**
* Excel导入
*/
@PostMapping("/import")
public Result userImport(@RequestParam("file") MultipartFile file) throws Exception{
System.out.println(file.toString());
//InputStream inputStream = multipartFile.getInputStream();
InputStream inputStream = file.getInputStream();
ExcelReader reader = ExcelUtil.getReader(inputStream);
//读取表的内容
List<List<Object>> list = reader.read(1);
List<User> users = new ArrayList<>();
for(List<Object> row : list){
User user = new User();
user.setUname(row.get(0).toString());
user.setUpassword(row.get(1).toString());
user.setUsex(row.get(2).toString());
user.setRole(row.get(3).toString());
user.setUlove(Integer.valueOf(row.get(4).toString()));
user.setUphoto(row.get(5).toString());
user.setUaddress(row.get(6).toString());
users.add(user);
}
//批量插入用户信息 mybatis-plus
userService.saveBatch(users);
return Result.success();
}3.导出demo
/**
* Excel导出 方法一
*/
@GetMapping("/export")
public Result userExport(HttpServletResponse response) throws Exception{
//查询全部的用户数据
List<User> list = userService.list();
//在内存里做操作，保存到浏览器
ExcelWriter writer = ExcelUtil.getWriter(true);
//自定义标题别名
writer.addHeaderAlias("uname","用户名");
writer.addHeaderAlias("upassword","密码");
writer.addHeaderAlias("usex","性别");
writer.addHeaderAlias("role","角色");
writer.addHeaderAlias("ulove","爱心值");
writer.addHeaderAlias("uphoto","电话号码");
writer.addHeaderAlias("uaddress","地址");
//一次性写出list内的对象的Excel，使用默认样式，强制输出标题
writer.write(list,true);
//设置浏览器响应格式
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
String filName= URLEncoder.encode("用户信息","UTF-8");
response.setHeader("Content-Disposition","attachment;filename="+filName+".xls");
ServletOutputStream outputStream=response.getOutputStream();
writer.flush(outputStream,true);
outputStream.close();
writer.close();
return Result.success();
}