How to fix the issue of Java POI failing to export Excel format properly?

If Excel format is not working when exporting using POI, there are several possible solutions: 1. Check if the cell styles are correctly set. When exporting Excel using POI, you need to create a CellStyle object and set the corresponding style properties, such as font, color, border, etc. Make sure you set the cell styles correctly to ensure the format takes effect. 2. Check if styles are correctly applied to cells. When exporting Excel using POI, you need to apply the CellStyle object to the corresponding cells by calling the setCellStyle method of the cell. Make sure you apply styles correctly to cells. 3. Check if the default style of the workbook is set correctly. When exporting Excel using POI, you can create a default style by calling the createCellStyle method of the Workbook and apply it to all the cells in the workbook using the setCellStyle method. Make sure you set the default style of the workbook correctly. 4. Check if the column width and row height are set correctly. When exporting Excel using POI, you can set the column width and row height by calling the setColumnWidth and setRowHeight methods of the Sheet. Make sure you set the column width and row height correctly to ensure the format takes effect. 5. Check if the cell data types are set correctly. When exporting Excel using POI, you need to set the correct data types for cells, such as text, number, date, etc. Make sure you set the data types of cells correctly to ensure the format takes effect. If none of the above methods solve the issue, you can provide more specific code and problem descriptions for better assistance.