POJO

This chapter introduces how to write data by configuring POJO classes.

Export Only Specified Columns Based on Parameters

Overview

Dynamically select columns to export by setting a collection of column names, supporting ignoring columns or exporting only specific columns.

The collection holds POJO field names, not header titles. Both examples below use the DemoData class and the data() method from Simple Writing, whose fields are string, date and doubleData.

Code Examples

Ignore Specified Columns

Everything except the listed fields is written:

@Test
public void excludeColumnWrite() {
    String fileName = "excludeColumnFieldWrite" + System.currentTimeMillis() + ".xlsx";

    Set<String> excludeColumns = Collections.singleton("date");
    FesodSheet.write(fileName, DemoData.class)
        .excludeColumnFieldNames(excludeColumns)
        .sheet()
        .doWrite(data());
}

Result

The date field is gone, the other two remain:

	A	B
1	String Title	Number Title
2	String0	0.56
3	String1	0.56
4	String2	0.56
⋮	…	…
11	String9	0.56

Export Only Specified Columns

Only the listed fields are written:

@Test
public void includeColumnWrite() {
    String fileName = "includeColumnFieldWrite" + System.currentTimeMillis() + ".xlsx";

    Set<String> includeColumns = Collections.singleton("date");
    FesodSheet.write(fileName, DemoData.class)
        .includeColumnFieldNames(includeColumns)
        .sheet()
        .doWrite(data());
}

Result

Only the date field is kept:

	A
1	Date Title
2	2026-07-31 20:50:23
3	2026-07-31 20:50:23
4	2026-07-31 20:50:23
⋮	…
11	2026-07-31 20:50:23

---

Specify Column Order for Writing

Overview

Specify column order.

POJO Class

@Getter
@Setter
@EqualsAndHashCode
public class IndexData {
    @ExcelProperty(value = "String Title", index = 0)
    private String string;
    @ExcelProperty(value = "Date Title", index = 1)
    private Date date;
    @ExcelProperty(value = "Number Title", index = 3)
    private Double doubleData;
}

Code Example

index attribute

Using the index attribute of the @ExcelProperty annotation.

@Test
public void indexWrite() {
    String fileName = "indexWrite" + System.currentTimeMillis() + ".xlsx";
    FesodSheet.write(fileName, IndexData.class)
        .sheet()
        .doWrite(data());
}

Result

	A	B	C	D
1	String Title	Date Title		Number Title
2	String0	2026-07-31 20:50:23		0.56
3	String1	2026-07-31 20:50:23		0.56
4	String2	2026-07-31 20:50:23		0.56
⋮	…	…		…
11	String9	2026-07-31 20:50:23		0.56

note

Column C is empty on purpose. index is an absolute, 0-based column position, not a sort key: the fields declare 0, 1 and 3, so nothing is written at position 2 and the gap is preserved in the output. To place the three columns side by side, number them 0, 1, 2.

includeColumnFieldNames

The columns come out in the POJO's order, not the collection's. Listing doubleData before string still writes string first, because that is the order the fields are declared in:

@Test
public void includeColumnOrderWrite() {
    String fileName = "includeColumnFieldWrite" + System.currentTimeMillis() + ".xlsx";

    Set<String> includeColumns = new LinkedHashSet<>(Arrays.asList("doubleData", "string"));
    FesodSheet.write(fileName, DemoData.class)
        .includeColumnFieldNames(includeColumns)
        .sheet()
        .doWrite(data());
}

Result

	A	B
1	String Title	Number Title
2	String0	0.56
⋮	…	…

orderByIncludeColumn

Add .orderByIncludeColumn(true) to follow the collection's order instead:

@Test
public void orderByIncludeColumnWrite() {
    String fileName = "includeColumnFieldWrite" + System.currentTimeMillis() + ".xlsx";

    Set<String> includeColumns = new LinkedHashSet<>(Arrays.asList("doubleData", "string"));
    FesodSheet.write(fileName, DemoData.class)
        .includeColumnFieldNames(includeColumns)
        .orderByIncludeColumn(true)
        .sheet()
        .doWrite(data());
}

Result

	A	B
1	Number Title	String Title
2	0.56	String0
⋮	…	…

The collection needs a stable iteration order for this - a LinkedHashSet or a List, not a HashSet.

---

Writing Without Creating Objects

Overview

Write data directly using List<List<String>> to define headers and data without creating entity classes.

Code Example

@Test
public void noModelWrite() {
    String fileName = "noModelWrite" + System.currentTimeMillis() + ".xlsx";

    FesodSheet.write(fileName)
        .head(head()) // Dynamic headers
        .sheet("Write Without Object")
        .doWrite(dataList());
}

private List<List<String>> head() {
    return Arrays.asList(
        Collections.singletonList("String Title"),
        Collections.singletonList("Number Title"),
        Collections.singletonList("Date Title"));
}

private List<List<Object>> dataList() {
    List<List<Object>> list = new ArrayList<>();
    for (int i = 0; i < 10; i++) {
        list.add(Arrays.asList("String" + i, 0.56, new Date()));
    }
    return list;
}

Result

	A	B	C
1	String Title	Number Title	Date Title
2	String0	0.56	2026-07-31 20:50:23
3	String1	0.56	2026-07-31 20:50:23
4	String2	0.56	2026-07-31 20:50:23
⋮	…	…	…
11	String9	0.56	2026-07-31 20:50:23