Formatting

This chapter introduces data formatting when reading data.

Custom Format Reading

Overview

When reading Excel files, date and number cells can be automatically converted to formatted String values using annotations. This is useful when you want to control the exact text representation of dates and numbers.

POJO Class

@Getter
@Setter
@EqualsAndHashCode
public class ConverterData {
    @ExcelProperty(value = "String Title", converter = CustomStringStringConverter.class)
    private String string;

    @DateTimeFormat("yyyy-MM-dd HH:mm:ss")
    @ExcelProperty("Date Title")
    private String date;

    @NumberFormat("#.##%")
    @ExcelProperty("Number Title")
    private String doubleData;
}

Conversion Behavior

Excel Cell Value	Annotation	Java Field Value
Hello	@ExcelProperty(converter = CustomStringStringConverter.class)	"Custom: Hello"
2025-01-01 12:30:00	@DateTimeFormat("yyyy-MM-dd HH:mm:ss")	"2025-01-01 12:30:00"
0.56	@NumberFormat("#.##%")	"56%"

tip

All fields in the POJO are String type. Fesod applies the configured converter/format to transform the raw Excel cell value before setting the field.

Code Example

@Test
public void converterRead() {
    String fileName = "path/to/demo.xlsx";

    FesodSheet.read(fileName, ConverterData.class, new PageReadListener<ConverterData>(dataList -> {
        for (ConverterData data : dataList) {
            log.info("Read a row of data: {}", JSON.toJSONString(data));
        }
    })).sheet().doRead();
}

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Annotation Reference

@DateTimeFormat

Converts date cells to formatted strings when the field type is String.

Parameter	Default	Description
value	Empty	Date format pattern, refer to java.text.SimpleDateFormat
use1904windowing	Auto	Set to true if the Excel file uses the 1904 date system

@NumberFormat

Converts number cells to formatted strings when the field type is String.

Parameter	Default	Description
value	Empty	Number format pattern, refer to java.text.DecimalFormat
roundingMode	HALF_UP	Rounding mode when formatting