Implement Subtotal feature of Excel

Question

Excel provides the Subtotal option from the Menu Data -> Outline -> Subtotal. It creates automatically the sub-sums and the possibility to fold the data. The image below demonstrates how the action transforms the sheet.

And this is exactly what I need to do via POI. I know how to set a subtotal function into a cell so I could calculate the intermediate sums by myself. But how do I enable this folding on the left border?

I realised there is the groupRow() method but those nested groups doesn't work like they should. If I use the following code I only get two groups. One large (1-7) and (1-3). The group (5-7) is missing and changing the order of the calls has no effect.

sheet.groupRow(1, 7);
sheet.groupRow(1, 3);
sheet.groupRow(5, 7);

Answer 1

I use a quite old verion of POI but this is how I did it:
I also needed multiple nested groups so I had a model for the rows where the indent level was stored as well (it was a tree so the indent was implicit). I traversed the model with a visitor to get the group start and end row numbers. Then called HSSFSheet.groupRow subsequently for each group. If I remember correctly, the order of the group calls is important.

Answer 2

I think this is exactly what you are looking for:

http://www.mysamplecode.com/2011/10/apache-poi-excel-row-group-collapse.html

if you use subtotal(9,<range>) instead of sum(<range>), you can perform nested groups as subtotal ignores cell with subtotal in its range

Answer 3

With following library you can to calculate the subtotals that you want

<dependency>
  <groupId>com.github.bld-commons.excel</groupId>
  <artifactId>generator-excel</artifactId>
  <version>3.1.1</version>
</dependency>

This library is wrapper of apache poi.
Below the source code:

1. You create a class that represents the row of the table.

package bld.generator.report.junit.entity;

import org.apache.poi.ss.usermodel.DataConsolidateFunction;
import org.apache.poi.ss.usermodel.HorizontalAlignment;

import bld.generator.report.excel.RowSheet;
import bld.generator.report.excel.annotation.ExcelCellLayout;
import bld.generator.report.excel.annotation.ExcelColumn;
import bld.generator.report.excel.annotation.ExcelFont;
import bld.generator.report.excel.annotation.ExcelSubtotal;
import bld.generator.report.excel.annotation.ExcelSubtotals;

@ExcelSubtotals(labelTotalGroup = "Total",endLabel = "total")
public class SalaryRow implements RowSheet {

    @ExcelColumn(columnName = "Name", indexColumn = 0)
    @ExcelCellLayout
    private String name;
    @ExcelColumn(columnName = "Amount", indexColumn = 1)
    @ExcelCellLayout(horizontalAlignment = HorizontalAlignment.RIGHT)
    @ExcelSubtotal(dataConsolidateFunction = DataConsolidateFunction.SUM,excelCellLayout = @ExcelCellLayout(horizontalAlignment = HorizontalAlignment.RIGHT,font=@ExcelFont(bold = true)))
    private Double amount;
    
    public SalaryRow() {
        super();
    }
    public SalaryRow(String name, Double amount) {
        super();
        this.name = name;
        this.amount = amount;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Double getAmount() {
        return amount;
    }
    public void setAmount(Double amount) {
        this.amount = amount;
    }
    
}

2. You create a class that represents the sheet.

package bld.generator.report.junit.entity;

import javax.validation.constraints.Size;

import bld.generator.report.excel.SheetData;
import bld.generator.report.excel.annotation.ExcelHeaderLayout;
import bld.generator.report.excel.annotation.ExcelMarginSheet;
import bld.generator.report.excel.annotation.ExcelSheetLayout;
@ExcelSheetLayout
@ExcelHeaderLayout
@ExcelMarginSheet(bottom = 1.5,left = 1.5,right = 1.5,top = 1.5)
public class SalarySheet extends SheetData<SalaryRow> {

    public SalarySheet(@Size(max = 31) String sheetName) {
        super(sheetName);
    }

}

3. Class test

package bld.generator.report.junit;

import java.util.ArrayList;
import java.util.List;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import bld.generator.report.excel.BaseSheet;
import bld.generator.report.excel.GenerateExcel;
import bld.generator.report.excel.data.ReportExcel;
import bld.generator.report.junit.entity.SalaryRow;
import bld.generator.report.junit.entity.SalarySheet;
import bld.generator.report.utils.ExcelUtils;


@RunWith(SpringRunner.class)
@SpringBootTest
@ConfigurationProperties
@ComponentScan(basePackages = {"bld.generator","bld.read"})
@EnableTransactionManagement
public class SalaryTest {

    private static final String PATH_FILE = "/mnt/report/";

    @Autowired
    private GenerateExcel generateExcel;

    /**
     * Sets the up.
     *
     * @throws Exception the exception
     */
    @Before
    public void setUp() throws Exception {
    }

    @Test
    public void testSalary() throws Exception {
        List<BaseSheet> listBaseSheet = new ArrayList<>();
        SalarySheet salarySheet=new SalarySheet("salary");
        salarySheet.getListRowSheet().add(new SalaryRow("a",2.0));
        salarySheet.getListRowSheet().add(new SalaryRow("a",2.0));
        salarySheet.getListRowSheet().add(new SalaryRow("a",2.0));
        salarySheet.getListRowSheet().add(new SalaryRow("a",2.0));
        salarySheet.getListRowSheet().add(new SalaryRow("c",1.0));
        salarySheet.getListRowSheet().add(new SalaryRow("c",1.0));
        salarySheet.getListRowSheet().add(new SalaryRow("c",1.0));
        salarySheet.getListRowSheet().add(new SalaryRow("c",1.0));
        listBaseSheet.add(salarySheet);
        
        ReportExcel report=new ReportExcel("test", listBaseSheet);
        
        byte[] byteReport = this.generateExcel.createFileXlsx(report);
        ExcelUtils.writeToFile(PATH_FILE,report.getTitle(), ".xlsx", byteReport);
        
    }
    
    

}

Below the link of the project on github:

• https://github.com/bld-commons/dev-excel

Below the result.
enter image description here