Spreadsheet Management with Aspose.Cells FOSS for Java

Aspose.Cells FOSS for Java is a pure-Java 17, MIT-licensed library for creating and manipulating Excel .xlsx workbooks without any Microsoft Office dependency. This post walks through the most common spreadsheet management operations: creating workbooks, loading files, working with cells, and saving results.

Setting Up

Add the Maven dependency to your pom.xml:

<dependency>
  <groupId>com.aspose</groupId>
  <artifactId>aspose-cells-foss</artifactId>
  <version>1.0.0</version>
</dependency>

No license file or API key is required. The library is fully open-source under MIT.

Creating a Workbook

The Workbook() constructor creates a new, blank workbook with one default sheet:

import com.aspose.cells.foss.Workbook;
import com.aspose.cells.foss.Worksheet;

Workbook workbook = new Workbook();
Worksheet sheet = workbook.getWorksheets().get(0);
System.out.println(sheet.getName()); // Sheet1

Use WorksheetCollection.add(sheetName) to add named sheets and removeAt(sheetName) to remove them:

int idx = workbook.getWorksheets().add("Report");
workbook.getWorksheets().get(idx).setName("Report");
workbook.getWorksheets().removeAt("Sheet1");

Loading an Existing File

Pass a file path to Workbook(fileName) to open an existing .xlsx workbook:

Workbook workbook = new Workbook("data/report.xlsx");
System.out.println("Sheets: " + workbook.getWorksheets().getCount());

For input streams (e.g. from a database or HTTP response), use Workbook(stream):

try (java.io.InputStream is = new java.io.FileInputStream("data/report.xlsx")) {
    Workbook workbook = new Workbook(is);
}

Reading and Writing Cells

Worksheet.getCells() returns the Cells collection. Access individual cells by name or by zero-based row/column index:

import com.aspose.cells.foss.Cells;
import com.aspose.cells.foss.Cell;

Cells cells = workbook.getWorksheets().get(0).getCells();

// Write by cell name
cells.get("A1").putValue("Product");
cells.get("B1").putValue("Revenue");

// Write by row/column index
cells.get(1, 0).putValue("Widget A");   // A2
cells.get(1, 1).putValue(45000);        // B2

// Read back
String name = cells.get("A2").getStringValue();
Object rev  = cells.get("B2").getValue();
System.out.println(name + ": " + rev);

Setting Formulas

Assign a formula string via Cell.setFormula():

cells.get("B3").setFormula("=SUM(B2:B2)");
System.out.println(cells.get("B3").getFormula()); // =SUM(B2:B2)

Formula results are resolved when the workbook is saved and reloaded.

Saving the Workbook

Workbook.save(fileName) writes the workbook; the format is determined by the file extension (.xlsx produces an Excel 2007+ file):

workbook.save("output/result.xlsx");

Always wrap large workbooks in try-with-resources to release file handles promptly:

try (Workbook workbook = new Workbook("data/input.xlsx")) {
    workbook.getWorksheets().get(0).getCells().get("A1").putValue("Updated");
    workbook.save("data/output.xlsx");
}

What to Explore Next

Aspose.Cells FOSS for Java supports a broad spreadsheet API beyond basic cell manipulation:

  • Worksheet protection: protect() / unprotect() on Worksheet
  • AutoFilter: Worksheet.getAutoFilter() for programmatic data filtering
  • Cell styles: Cell.getStyle() / setStyle() with Style properties
  • Merged cells: Cells.merge(firstRow, firstColumn, totalRows, totalColumns)

For a full API walkthrough, see the developer guide and the API reference.