您需要：

1. 将数据设置为数字（浮点数），而不是文本。


2. 指定单元格格式为百分比。

类似于：

  cell.setCellValue（0.123）; //将值设置为number 
 CellStyle style = workbook.createCellStyle（）; 
 style.setDataFormat（workbook.createDataFormat（）。getFormat（0.000％））; 
 cell.setCellStyle（style）; 
 

查看用户定义的格式部分。您也可以浏览示例，该示例展示如何使用不同的POI功能。 / p>

I need to display a value in an excel cell formatted like a percentage, e.g. like 12.3%.

By default the value is displayed as Text, but I need to display it as a number.

What is the appropriate method to achieve this?

You need to:

1. Set your data as number (floating-point), not as text.
2. Specify cell format as percentage.

Something like:

cell.setCellValue(0.123); // set value as number
CellStyle style = workbook.createCellStyle();
style.setDataFormat(workbook.createDataFormat().getFormat("0.000%"));
cell.setCellStyle(style);

Take a look at user defined formats section of POI quick guide for more details. You may also want to go through the examples which show how to use different POI capabilities.