@Test
    public void simpleFill() {
        // Template note: Use {} to represent variables. If the template contains "{", "}" as special characters, use "\{", "\}" instead.
        String templateFileName = "src/test/resources/fill/simple.xlsx";

        // Option 1: Fill using an object
        String fileName = TestFileUtil.getPath() + "simpleFill" + System.currentTimeMillis() + ".xlsx";
        // This will fill the first sheet, and the file stream will be closed automatically.
        FillData fillData = new FillData();
        fillData.setName("Zhang San");
        fillData.setNumber(5.2);
        EasyExcel.write(fileName).withTemplate(templateFileName).sheet().doFill(fillData);

        /*
        // Option 2: Fill using a Map
        fileName = TestFileUtil.getPath() + "simpleFill" + System.currentTimeMillis() + ".xlsx";
        // This will fill the first sheet, and the file stream will be closed automatically.
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("name", "Zhang San");
        map.put("number", 5.2);
        EasyExcel.write(fileName).withTemplate(templateFileName).sheet().doFill(map);
        */
    }
Simplest example of filling data.

@since 2.1.1
fastexcel-test/src/test/java/cn/idev/excel/test/temp/fill/FillTempTest.java