无法在删除重复行后使用Apache POI编写新的excel

Question

我是Apache POI的新手。

我写了一个小代码，用于从excel文件中删除重复的记录。我可以成功地识别跨页的重复记录，但在删除记录后写入新文件时，不会生成输出。

请帮我在哪里布莱恩错了？

我是否正确书写？或者我错过了什么？

public static void main(String args[]) { 
    DataFormatter formatter = new DataFormatter(); 
    HSSFWorkbook input_workbook; 
    HSSFWorkbook workbook_Output_Final; 

    HSSFSheet input_workbook_sheet; 

    HSSFRow row_Output; 
    HSSFRow row_1_index; 
    HSSFRow row_2_index; 

    String value1 = ""; 
    String value2 = ""; 
    int count; 


    //main try catch block starts 
    try { 

     FileInputStream input_file = new FileInputStream("E:\\TEST\\Output.xls"); //reading from input file 
     input_workbook = new HSSFWorkbook(new POIFSFileSystem(input_file)); 

     for (int sheetnum = 0; sheetnum < input_workbook.getNumberOfSheets(); sheetnum++) { //traversing sheets 

      input_workbook_sheet = input_workbook.getSheetAt(sheetnum); 

      int input_workbook_sheet_total_row = input_workbook_sheet.getLastRowNum(); //fetching last row nmber 

      for (int input_workbook_sheet_row_1 = 0; input_workbook_sheet_row_1 <= input_workbook_sheet_total_row; input_workbook_sheet_row_1++) { //traversing row 1 

       for (int input_workbook_sheet_row_2 = 0; input_workbook_sheet_row_2 <= input_workbook_sheet_total_row; input_workbook_sheet_row_2++) { 

        row_1_index = input_workbook_sheet.getRow(input_workbook_sheet_row_1); //fetching one iteration row index 
        row_2_index = input_workbook_sheet.getRow(input_workbook_sheet_row_2); //fetching sec iteration row index 

        if (row_1_index != row_2_index) { 
         count = 0; 
         value1 = ""; 
         value2 = ""; 
         for (int row_1_index_cell = 0; row_1_index_cell < row_1_index.getLastCellNum(); row_1_index_cell++) { //traversing cell for each row 
          try { 
           value1 = value1 + formatter.formatCellValue(row_1_index.getCell(row_1_index_cell)); //fetching row cells value 
           value2 = value2 + formatter.formatCellValue(row_2_index.getCell(row_1_index_cell)); //fetching row cells value 

          } catch (NullPointerException e) { 
          } 
          count++; 
          if (count == row_1_index.getLastCellNum()) { 

           if (value1.hashCode() == value2.hashCode()) { //remove the duplicate logic 
            System.out.println("deleted : " + row_2_index); 
            System.out.println("------------------"); 
            input_workbook_sheet.removeRow(row_2_index); 
           } 

          } 
         } 

        } 
       } 
      } 

     } 
     FileOutputStream fileOut = new FileOutputStream("E:\\TEST\\workbook.xls"); 
     input_workbook.write(fileOut); 
     fileOut.close(); 
     input_file.close(); 
    } catch (Exception e) { 
     //e.printStackTrace(); 
    } 
    //main try catch block ends 

} 

Answer 1

几件事情需要注意：

1. 你吞下任何一种异常的;与我的测试数据Igotsome nullpointers，这将阻止工作簿被写入

2. 当删除行时，往回移动行号是一个古老的技巧，因为那么你不必调整行号您刚删除

3. 该代码清空行，但它不会向上移动所有行（=删除后有间隙）。如果你想消除这个差距，你可以使用shiftRows

4. 你用hashcode比较东西，这是可能的（在某些使用情况下），但我觉得你想要做.equals（）。又见Relationship between hashCode and equals method in Java

下面是一些代码，工作了我的测试数据，随意评论，如果事情不与您的数据的工作：

public static void main(String args[]) throws IOException { 
    DataFormatter formatter = new DataFormatter(); 
    HSSFWorkbook input_workbook; 
    HSSFWorkbook workbook_Output_Final; 

    HSSFSheet input_workbook_sheet; 

    HSSFRow row_Output; 
    HSSFRow row_1_index; 
    HSSFRow row_2_index; 

    String value1 = ""; 
    String value2 = ""; 
    int count; 

    FileInputStream input_file = new FileInputStream("c:\\temp\\test.xls"); 
    input_workbook = new HSSFWorkbook(new POIFSFileSystem(input_file)); 

    for (int sheetnum = 0; sheetnum < input_workbook.getNumberOfSheets(); sheetnum++) { 

     input_workbook_sheet = input_workbook.getSheetAt(sheetnum); 

     int input_workbook_sheet_total_row = input_workbook_sheet.getLastRowNum(); 

     for (int input_workbook_sheet_row_1 = input_workbook_sheet_total_row; input_workbook_sheet_row_1 >=0; input_workbook_sheet_row_1--) { // traversing 

      for (int input_workbook_sheet_row_2 = input_workbook_sheet_total_row; input_workbook_sheet_row_2 >= 0 ; input_workbook_sheet_row_2--) { 

       row_1_index = input_workbook_sheet.getRow(input_workbook_sheet_row_1); 
       row_2_index = input_workbook_sheet.getRow(input_workbook_sheet_row_2); 

       if (row_1_index != null && row_2_index != null && row_1_index != row_2_index) { 
        count = 0; 
        value1 = ""; 
        value2 = ""; 

        int row_1_max = row_1_index.getLastCellNum() - 1; 
        for (int row_1_index_cell = 0; row_1_index_cell < row_1_max; row_1_index_cell++) { 
         try { 
          value1 = value1 + formatter.formatCellValue(row_1_index.getCell(row_1_index_cell)); 

          value2 = value2 + formatter.formatCellValue(row_2_index.getCell(row_1_index_cell)); 

         } catch (NullPointerException e) { 
          e.printStackTrace(); 
         } 
         count++; 

         if (value1.equals(value2)) { 
          System.out.println("deleted : " + row_2_index.getRowNum()); 
          System.out.println("------------------"); 
          input_workbook_sheet.removeRow(row_2_index); 


          input_workbook_sheet.shiftRows(
            row_2_index.getRowNum() + 1, 
            input_workbook_sheet_total_row, 
            -1, 
            true, 
            true); 
         } 


        } 

       } 
      } 
     } 

    } 
    FileOutputStream fileOut = new FileOutputStream("c:\\temp\\workbook.xls"); 
    input_workbook.write(fileOut); 
    fileOut.close(); 
    input_file.close(); 
    input_workbook.close(); 
}