在Java Eclipse中，我从数据库中检索了数据，并粘贴在已经存在的Excel中.已经存在的数据已被删除

Question

在Java Eclipse中，我进行了查询以从数据库中检索数据并粘贴在C驱动器中已经存在的Excel表（Exceldatabase16）中。已经存在Excel -exceldatabase16在第一行中包含列名。粘贴到Exceldatabase16中的数据从第6行粘贴到列F。第1行数据仍被删除。

。

public static  void retrieveData1( Connection connection) throws SQLException, IOException 
    {
         Statement stmt = null;
           ResultSet rs = null;
         stmt = connection.createStatement();

         rs = stmt.executeQuery("SELECT * FROM countries where region_id='3' ");
//         getColumnNames(rs);

         XSSFWorkbook workbook = new XSSFWorkbook(); 
         XSSFSheet spreadsheet = workbook.createSheet("countriesdetails");
         XSSFRow row = spreadsheet.createRow(5);
         XSSFCell cell;
         cell = row.createCell(5);
         cell.setCellValue("country id");
         cell = row.createCell(6);
         cell.setCellValue("country name");
         cell = row.createCell(7);
         cell.setCellValue("region");
         int i = 6;
         while(rs.next()) {
            row = spreadsheet.createRow(i);
            cell = row.createCell(5);      
            cell.setCellValue(rs.getString(1));
            cell = row.createCell(6);
            cell.setCellValue(rs.getString(2));
            cell = row.createCell(7);
            cell.setCellValue(rs.getInt(3));
            i++;
         }
         FileOutputStream out = new FileOutputStream(new File("C:\Users\lenovo\workspace\ApachePoi\exceldatabase16.xlsx"));
         workbook.write(out);
         out.close();
         workbook.close();
         System.out.println("exceldatabase.xlsx written successfully");     
     }

Answer 1

每当您运行此程序时，您似乎正在用新文件覆盖现有文件。

根据XSSF文档，XSSFWorkbook创建的方法签名可以打开现有文件而不是制作新文件。

尝试以下内容：

 XSSFWorkbook workbook = new XSSFWorkbook(new FileInputStream("C:\Users\lenovo\workspace\ApachePoi\exceldatabase16.xlsx"));