java SXSSFWorkbook 上的 AutosizeColumns
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AutosizeColumns on SXSSFWorkbook
提问by sterym
Is it possible to autoSizeColumns on a streaming SXSSFWorkbook? I implemented an export functionality to export a list of objects to excel. At first I used the XSSFWorkbook (not streaming) and after all the cells were created, I autosized all the columns, resulting in a nice excel file.
是否可以在流式 SXSSFWorkbook 上使用 autoSizeColumns？我实现了一个导出功能，将对象列表导出到 excel。起初我使用了 XSSFWorkbook（不是流媒体），在创建了所有单元格之后，我自动调整了所有列的大小，从而生成了一个不错的 excel 文件。
For performance issues we wanted to change the workbook to the streaming version, but this resulted in a NullPointer at org.apache.poi.ss.util.SheetUtil.getCellWidth.
对于性能问题，我们希望将工作簿更改为流式版本，但这导致 org.apache.poi.ss.util.SheetUtil.getCellWidth 处出现 NullPointer。
Is it possible to call autoSizeColumns for a SXSSFWorkbook?
是否可以为 SXSSFWorkbook 调用 autoSizeColumns？
Im using poi-ooxml 3.9, but I have the same issue in 3.8.
我使用的是 poi-ooxml 3.9，但我在 3.8 中遇到了同样的问题。
采纳答案by cremersstijn
You need to make sure every cell has a value.
您需要确保每个单元格都有一个值。
We use the following code to set a string value to a cell:
我们使用以下代码为单元格设置字符串值：
Cell c = row.createCell(i);
c.setCellValue(text == null ? "" : text );
** Cell should never be null values else it throws NullPointerException. Hence set the value as shown above.
** 单元格不应该是空值，否则它会抛出 NullPointerException。因此设置如上所示的值。
Thanks a lot, this helped!!
非常感谢，这有帮助！！
回答by Virendra khade
Use sheet.isColumnTrackedForAutoSizing(0);for first and subsequently used for other column, i have faced exception whenever code executed autoSizeColumn(0) get executed. by using above code i have resolved the issue and it's good to expand the column width too based on the text.
使用sheet.isColumnTrackedForAutoSizing(0); 对于第一列并随后用于其他列，每当执行代码 autoSizeColumn(0) 时，我都会遇到异常。通过使用上面的代码，我已经解决了这个问题，并且根据文本扩展列宽也很好。
回答by Srini Yedire
Error: NullPointerExceptionon org.apache.poi.ss.util.SheetUtil.getCellWidth(SheetUtil.java:122)
错误：NullPointerExceptiononorg.apache.poi.ss.util.SheetUtil.getCellWidth(SheetUtil.java:122)
Fix: Always set value to Cell as shown below, it throws NullPointerException when there is null in Cell, so set the value as:
修复：总是如下图设置值给Cell，当Cell为null时会抛出NullPointerException，所以设置值为：
Cell c = row.createCell(i);
c.setCellValue(text == null ? "" : text );
