java easyexcel 合并单元格

在使用 EasyExcel 库进行单元格合并时，可以使用 `WriteSheet` 的 `merge` 方法来实现。以下是一个示例代码：

// 导入相关的类
import com.alibaba.excel.EasyExcel;import com.alibaba.excel.write.merge.OnceAbsoluteMergeStrategy;
import com.alibaba.excel.write.metadata.WriteSheet;

public class ExcelMergeCellsExample {
    public static void main(String[] args) {
        // 创建一个 ExcelWriter 对象
        String fileName = "path/to/your/excel/file.xlsx";
        ExcelWriter excelWriter = EasyExcel.write(fileName).build();
        
        // 创建一个 WriteSheet 对象
        WriteSheet writeSheet = EasyExcel.writerSheet("Sheet1").build();
        
        // 定义合并的起始行、起始列、结束行、结束列
        int firstRow = 1;
        int lastRow = 3;
        int firstCol = 1;
        int lastCol = 4;
        
        // 创建一个合并策略对象
        OnceAbsoluteMergeStrategy mergeStrategy = new OnceAbsoluteMergeStrategy(firstRow, lastRow, firstCol, lastCol);
        
        // 设置合并策略
        writeSheet.setWriteHandler(mergeStrategy);
        
        // 写入数据到 Excel 文件
        List<List<String>> data = new ArrayList<>();
        data.add(Arrays.asList("A1", "B1", "C1", "D1"));
        data.add(Arrays.asList("A2", "B2", "C2", "D2"));
        data.add(Arrays.asList("A3", "B3", "C3", "D3"));
        excelWriter.write(data, writeSheet);
        
        // 关闭 ExcelWriter
        excelWriter.finish();
    }
}

在上述示例中，我们创建了一个 `ExcelWriter` 对象，然后定义了要合并的单元格的起始行、起始列、结束行和结束列。接下来