從excel列中抽取字符串數據到hashmap的問題

Question

我想從Java中抽取一些數據從Excel到Hashmap。爲此我使用的Apache POI庫和版本就是Java 8中的數據格式如下圖所示：

Excel_Data.xlsx: 

    Title | Label A | Label B | Label C 

    Signal 1 | value A1 | value B1 | value C1 
    Signal 2 | value A2 | value B2 | value C2 
    Signal 3 | value A3 | value B3 | value C3 

這裏寫的所有文字是String格式，並有出現在文件中沒有數值類型

我想要什麼：

我想存儲數據的key和value對形式的HashMap，所以我的輸出應該是：

Expected Approach: 

Key  -> Value 

Signal 1 -> [value A1, value B1, value C1 ...] 
Signal 2 -> [value A2, value B2, value C2 ...] 
Signal 3 -> [value A3, value B3, value C3 ...] 

這種方法我想實現，因爲我要到另一個excel文件下列信號

Expected_output.xlsx: 

Signal 1 | value A1 
     | value B1 
     | value C1 
Signal 2 | value A2 
     | value B2 
     | value C2 
Signal 3 | value A3 
     | value B3 
     | value C3 

順序我想什麼來打印這些數據：找到這個解決方案

我試着在網上，但由於其特殊性，我沒有找到任何解決方案。我也試圖找到解決方案，key和value都是從hashmap的excel中提取的String，但是也沒有得到太多幫助。

我想出了一個辦法，我決定來存儲Keys到String和Values到ArrayList如下圖所示代碼：

// this function loads data from excel file stored in filestream variable 
public void storeData(){ 
    //this hashmap will be used to hold values of excel file in key:values format 
    HashMap<String, ArrayList<String>> map = new HashMap<String, ArrayList<String>>(); 
    String key = null; 
    ArrayList<String> value = null; 

    try { 
     // get workbook instance of xlsx file 
     HSSFWorkbook workbook = new HSSFWorkbook(open_excel_data); 

     //Get first sheet from the workbook 
     HSSFSheet sheet = workbook.getSheetAt(0); 

     //Iterate through each rows from first sheet 
     Iterator<Row> rowIterator = sheet.iterator(); 

     while(rowIterator.hasNext()) { 
      Row row = rowIterator.next(); 

      // for each row, iterate through each columns 
      Iterator<Cell> cellIterator = row.cellIterator(); 

      while(cellIterator.hasNext()) 
      { 
       Cell cell = cellIterator.next(); 

       key = cell.getStringCellValue(); 

       value.add(cell.getStringCellValue()); // I cannot think of what should be here to store labels in correct format to arraylist 

       if(key != null && value != null) 
       { 
        map.put(key, value); 
        key = null; 
        value = null; 
       } 
      } 

     } 

    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 

} 

附：

• 它有很多的信號的一個巨大的文件和標籤

• 它使用Java來完成，因爲這功能將是一個已經建立的軟件工具的一部分

• 你甚至可以建議我其他簡單的方法來完成這項任務，如果你有任何想法

Answer 1

while(rowIterator.hasNext()) { 

    Row row = rowIterator.next(); 

    // for each row, iterate through each columns 
    Iterator<Cell> cellIterator = row.cellIterator(); 
    key = null; 
    value = new ArrayList<String>();  

    while(cellIterator.hasNext()) { 

     Cell cell = cellIterator.next(); 
     int columnIndex = cell.getColumnIndex(); 

     if(columnIndex == 1) { 
      key = cell.getStringCellValue(); 
     } else { 
      value.add(cell.getStringCellValue()); 
     } 
    } 

    if(key != null && value != null) { 
     map.put(key, value); 
     key = null; 
     value = null; 
    } 
} 

Answer 2

在你的代碼片段，你永遠不會crea爲'value'填充一個空的ArrayList。對於每一行你需要創建一個空的ArrayList，否則你不能添加值。此外，如果迭代行並遍歷單元格，則每行的第一個單元格中只包含密鑰。這種方式的關鍵和價值總是相同的。在第一個單元格條目中設置密鑰後，您不能覆蓋該密鑰。

Answer 3

// this function loads data from excel file stored in filestream variable 
    public HashMap<String, ArrayList<String>> storeData(String fileName) { 
     // this hashmap will be used to hold values of excel file in key:values 
     // format 
     HashMap<String, ArrayList<String>> map = new HashMap<String, ArrayList<String>>(); 
     String key = null; 
     ArrayList<String> value = null; 
     int keyIndex = 0; 
     try { 
      // get workbook instance of xlsx file 
      FileInputStream file = new FileInputStream(new File(fileName)); 
      HSSFWorkbook workbook = new HSSFWorkbook(file); 

      // Get first sheet from the workbook 
      HSSFSheet sheet = workbook.getSheetAt(0); 

      // Iterate through each rows from first sheet 
      Iterator<Row> rowIterator = sheet.iterator(); 

      while (rowIterator.hasNext()) { 
       Row row = rowIterator.next(); 
       key = null; 
       value = new ArrayList<String>(); 
       // for each row, iterate through each columns 
       Iterator<Cell> cellIterator = row.cellIterator(); 

       // To skip first row 
       if (row.getRowNum() == 0){ 
        continue; 
       } 

       while (cellIterator.hasNext()) { 
        Cell cell = cellIterator.next(); 
        cell.setCellType(Cell.CELL_TYPE_STRING); 
        if(cell.getColumnIndex() == keyIndex){ 
         key = cell.getStringCellValue(); 
        } else { 
         value.add(cell.getStringCellValue()); 
        } 

       } 

       if (key != null && value != null && value.size()>0) { 
        map.put(key, value); 
        key = null; 
        value = null; 
       } 

      } 

     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 

     return map; 
    }