<!--springboot核心依賴-->
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.3.4.RELEASE</version>
  </parent>
  <dependencies>
    <!--springboot-->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!--excel-->
    <dependency>
      <groupId>org.apache.poi</groupId>
      <artifactId>poi-ooxml</artifactId>
      <version>3.11</version>
    </dependency>
    <dependency>
      <groupId>org.apache.poi</groupId>
      <artifactId>poi</artifactId>
      <version>3.11</version>
    </dependency>
    <!--mybatis-plus-->
    <dependency>
      <groupId>com.baomidou</groupId>
      <artifactId>mybatis-plus-boot-starter</artifactId>
      <version>3.4.0</version>
    </dependency>
    <!--mysql-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>
  </dependencies>

public class POIUtils {
  private final static String xls = "xls";
  private final static String xlsx = "xlsx";
  private final static String DATE_FORMAT = "yyyy/MM/dd";
  /**
   * 讀入excel文件，解析后返回
   * @param file
   * @throws IOException
   */
  public static List<String> readExcel(MultipartFile file) throws IOException {
    //檢查文件
    checkFile(file);
    //獲得Workbook工作薄對(duì)象
    Workbook workbook = getWorkBook(file);
    //創(chuàng)建返回對(duì)象，把每行中的值作為一個(gè)數(shù)組，所有行作為一個(gè)集合返回
//    List<String[]> list = new ArrayList<String[]>();
    List<String> list = new ArrayList<>();
    if(workbook != null){
      for(int sheetNum = 0;sheetNum < workbook.getNumberOfSheets();sheetNum++){
        //獲得當(dāng)前sheet工作表
        Sheet sheet = workbook.getSheetAt(sheetNum);
        if(sheet == null){
          continue;
        }
        //獲得當(dāng)前sheet的開始行
        int firstRowNum = sheet.getFirstRowNum();
        //獲得當(dāng)前sheet的結(jié)束行
        int lastRowNum = sheet.getLastRowNum();
        //循環(huán)所有行
        for(int rowNum = firstRowNum;rowNum <= lastRowNum;rowNum++){
          //獲得當(dāng)前行
          Row row = sheet.getRow(rowNum);
          if(row == null){
            continue;
          }
          //獲得當(dāng)前行的開始列
          int firstCellNum = row.getFirstCellNum();
          //獲得當(dāng)前行的列數(shù)
          int lastCellNum = row.getPhysicalNumberOfCells();
//          String[] cells = new String[row.getPhysicalNumberOfCells()];
          //循環(huán)當(dāng)前行
          for(int cellNum = firstCellNum; cellNum <= lastCellNum;cellNum++){
            Cell cell = row.getCell(cellNum);
//            cells[cellNum] = getCellValue(cell);
            String cellValue = getCellValue(cell);
            list.add(cellValue);
          }

        }
      }
      workbook.close();
    }
    return list;
  }

  //校驗(yàn)文件是否合法
  public static void checkFile(MultipartFile file) throws IOException{
    //判斷文件是否存在
    if(null == file){
      throw new FileNotFoundException("文件不存在！");
    }
    //獲得文件名
    String fileName = file.getOriginalFilename();
    //判斷文件是否是excel文件
    if(!fileName.endsWith(xls) && !fileName.endsWith(xlsx)){
      throw new IOException(fileName + "不是excel文件");
    }
  }
  public static Workbook getWorkBook(MultipartFile file) {
    //獲得文件名
    String fileName = file.getOriginalFilename();
    //創(chuàng)建Workbook工作薄對(duì)象，表示整個(gè)excel
    Workbook workbook = null;
    try {
      //獲取excel文件的io流
      InputStream is = file.getInputStream();
      //根據(jù)文件后綴名不同(xls和xlsx)獲得不同的Workbook實(shí)現(xiàn)類對(duì)象
      if(fileName.endsWith(xls)){
        //2003
        workbook = new HSSFWorkbook(is);
      }else if(fileName.endsWith(xlsx)){
        //2007
        workbook = new XSSFWorkbook(is);
      }
    } catch (IOException e) {
      e.printStackTrace();
    }
    return workbook;
  }
  public static String getCellValue(Cell cell){
    String cellValue = "";
    if(cell == null){
      return cellValue;
    }
    //如果當(dāng)前單元格內(nèi)容為日期類型，需要特殊處理
    String dataFormatString = cell.getCellStyle().getDataFormatString();
    if(dataFormatString.equals("m/d/yy")){
      cellValue = new SimpleDateFormat(DATE_FORMAT).format(cell.getDateCellValue());
      return cellValue;
    }
    //把數(shù)字當(dāng)成String來讀，避免出現(xiàn)1讀成1.0的情況
    if(cell.getCellType() == Cell.CELL_TYPE_NUMERIC){
      cell.setCellType(Cell.CELL_TYPE_STRING);
    }
    //判斷數(shù)據(jù)的類型
    switch (cell.getCellType()){
      case Cell.CELL_TYPE_NUMERIC: //數(shù)字
        cellValue = String.valueOf(cell.getNumericCellValue());
        break;
      case Cell.CELL_TYPE_STRING: //字符串
        cellValue = String.valueOf(cell.getStringCellValue());
        break;
      case Cell.CELL_TYPE_BOOLEAN: //Boolean
        cellValue = String.valueOf(cell.getBooleanCellValue());
        break;
      case Cell.CELL_TYPE_FORMULA: //公式
        cellValue = String.valueOf(cell.getCellFormula());
        break;
      case Cell.CELL_TYPE_BLANK: //空值
        cellValue = "";
        break;
      case Cell.CELL_TYPE_ERROR: //故障
        cellValue = "非法字符";
        break;
      default:
        cellValue = "未知類型";
        break;
    }
    return cellValue;
  }
}

@RestController
@RequestMapping("/excel")
public class ExcelController {
  
  @PostMapping("/look")
  public void look(@RequestParam("excelFile") MultipartFile excelFile){
    try {
      List<String> list = POIUtils.readExcel(excelFile);
//      list.removeIf(Objects::isNull);去掉null值
      //去掉空字符串
      Iterator<String> iterator = list.iterator();
      while (iterator.hasNext()){
        if (iterator.next() == ""){
          iterator.remove();
        }
      }
      //遍歷list,查看數(shù)據(jù)
      for (String s : list) {
        System.out.println(s);
      }
      //創(chuàng)建map對(duì)象或者pojo類存入所需的數(shù)據(jù)，
      Map<String,Object> map = new HashMap<>();
      map.put("plan",list.get(0));
      map.put("er",list.get(2));
      map.put("date",list.get(4));
      System.out.println(map);

    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}