Springboot上传excel并将表格数据导入或更新mySql数据库的过程

<dependency> 
  <groupId>org.apache.poi</groupId> 
  <artifactId>poi-ooxml</artifactId> 
  <version>3.9</version> 
</dependency> 
<dependency> 
  <groupId>commons-fileupload</groupId> 
  <artifactId>commons-fileupload</artifactId> 
  <version>1.3.1</version> 
</dependency> 
<dependency> 
  <groupId>commons-io</groupId> 
  <artifactId>commons-io</artifactId> 
  <version>2.4</version> 
</dependency> 

@PostMapping("/save") 
public String addUser(@RequestParam("file") MultipartFile file) { 
 String fileName = file.getOriginalFilename(); 
 try { 
  return sysService.batchImport(fileName, file); 
 } catch (MyException e) { 
  e.printStackTrace(); 
  return e.getMessage(); 
 }catch(Exception e){ 
  e.printStackTrace(); 
  return "文件异常,导入失败"; 
   
 } 
} 

boolean import(String fileName, MultipartFile file) throws Exception; 

@Transactional(readOnly = false,rollbackFor = Exception.class) 
@Override 
public boolean import(String fileName, MultipartFile file) throws Exception { 
 Map<String, Integer> departmentMap = findDepartment(); 
 Map<String, Integer> roleMap = findRole(); 
 boolean notNull = false; 
  List<User> userList = new ArrayList<User>(); 
 if (!fileName.matches("^.+\\.(?i)(xls)$") && !fileName.matches("^.+\\.(?i)(xlsx)$")) { 
   throw new MyException("上传文件格式不正确"); 
 } 
 boolean isExcel2003 = true; 
 if (fileName.matches("^.+\\.(?i)(xlsx)$")) { 
  isExcel2003 = false; 
 } 
 InputStream is = file.getInputStream(); 
  Workbook wb = null; 
  if (isExcel2003) { 
   wb = new HSSFWorkbook(is); 
  } else { 
   wb = new XSSFWorkbook(is); 
  } 
  Sheet sheet = wb.getSheetAt(0); 
  if(sheet!=null){ 
   notNull = true; 
  } 
 User user; 
 for (int r = 1; r <= sheet.getLastRowNum(); r++) { 
  Row row = sheet.getRow(r); 
  if (row == null){ 
   continue; 
  } 
  user = new User(); 
  if( row.getCell(0).getCellType() !=1){ 
   throw new MyException("导入失败(第"+(r+1)+"行,ID单元格格式请设为文本格式)"); 
  } 
  String id = row.getCell(0).getStringCellValue(); 
  if(id==null || id.isEmpty()){ 
    throw new MyException("导入失败(第"+(r+1)+"行,ID未填写)"); 
  } 
  String name = row.getCell(1).getStringCellValue(); 
  if(name==null || name.isEmpty()){ 
    throw new MyException("导入失败(第"+(r+1)+"行,姓名未填写)"); 
  } 
  String department = row.getCell(2).getStringCellValue(); 
  if(departmentMap.get(department)==null){ 
    throw new MyException("导入失败(第"+(r+1)+"行,不存在此单位或单位未填写)"); 
  } 
  String role = row.getCell(3).getStringCellValue(); 
  if(roleMap.get(role)==null){ 
   throw new MyException("导入失败(第"+(r+1)+"行,不存在此角色或角色未填写)"); 
  } 
  Date date; 
  if(row.getCell(4).getCellType() !=0){ 
   throw new MyException("导入失败(第"+(r+1)+"行,入职日期格式不正确或未填写)"); 
   }else{ 
     date = row.getCell(4).getDateCellValue(); 
   } 
   user.setId(id); 
   user.setName(name); 
   user.setDepartmentId((int) departmentMap.get(department)); 
   user.setRoleId((int) roleMap.get(role)); 
   user.setDate(date); 
   userList.add(user); 
  } 
 for (User user : userList) { 
  String id = user.getId(); 
  int cnt = userMapper.selectById(id); 
  if (cnt == 0) { 
   userMapper.addUser(user); 
  } else { 
   userMapper.updateUserById(user); 
  } 
 } 
 return notNull; 
}