Cell merging in Excel combines two or more adjacent cells in the same row or column into a single cell. This article demonstrates how to use Free Spire.XLS for Java to merge and unmerge cells in Excel spreadsheets.

Prerequisites:

1. Download Free Spire.XLS for Java and extract the package. Add the Spire.Xls.jar file from the lib folder as a dependency in your Java project.
2. Alternatively, configure Maven to include the library by adding the following to your pom.xml:

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <url>http://repo.e-iceblue.cn/repository/maven-public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.xls.free</artifactId>
        <version>2.2.0</version>
    </dependency>
</dependencies>

Merging Cells:

The following example demonstrates how to merge a range of cells (A1 to C1) in an Excel worksheet:

import com.spire.xls.FileFormat;
import com.spire.xls.Workbook;
import com.spire.xls.Worksheet;

public class CellMerger {
    public static void main(String[] args) {
        // Initialize a new Workbook
        Workbook wb = new Workbook();
        
        // Load an existing Excel file
        wb.loadFromFile("input.xlsx");
        
        // Access the first worksheet
        Worksheet ws = wb.getWorksheets().get(0);
        
        // Merge the cell range from A1 to C1
        ws.getRange().get("A1:C1").merge();
        
        // Save the modified workbook
        wb.saveToFile("merged_output.xlsx", FileFormat.Version2013);
    }
}

Unmerging Cells:

To unmerge previously merged cels, use the unMerge() method as shown below:

import com.spire.xls.FileFormat;
import com.spire.xls.Workbook;
import com.spire.xls.Worksheet;

public class CellUnmerger {
    public static void main(String[] args) {
        // Initialize a new Workbook
        Workbook wb = new Workbook();
        
        // Load the Excel file containing merged cells
        wb.loadFromFile("merged_output.xlsx");
        
        // Access the first worksheet
        Worksheet ws = wb.getWorksheets().get(0);
        
        // Unmerge the cell range from A1 to C1
        ws.getRange().get("A1:C1").unMerge();
        
        // Save the result to a new file
        wb.saveToFile("unmerged_output.xlsx", FileFormat.Version2013);
    }
}

The merge() method accepts cell ranges in standard Excel notation (such as "A1:C1", "B2:E5", or "A1"), while the unMerge() method works on the same range format to restore individual cells.