@Test
    public void simpleFill() {
        // Template note: Use {} to indicate variables. If there are existing "{", "}" characters, use "\{", "\}" instead.
        String templateFileName =
            TestFileUtil.getPath() + "demo" + File.separator + "fill" + File.separator + "simple.xlsx";

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

        // Option 2: Fill based on a Map
        fileName = TestFileUtil.getPath() + "simpleFill" + System.currentTimeMillis() + ".xlsx";
        // This will fill the first sheet, and the file stream will be automatically closed.
        Map<String, Object> map = MapUtils.newHashMap();
        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/demo/fill/FillTest.java