Try This one...
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.FileInputStream;
public class ExcelRowAndColumnCount
{
public static void main(String args[]) throws Exception
{
FileInputStream file = new FileInputStream("D://TestData.xlsx");
XSSFWorkbook workbook = new XSSFWorkbook(file);
XSSFSheet sheet = workbook.getSheet("SheetName");
XSSFRow row = sheet.getRow(0);
int colNum = row.getLastCellNum();
System.out.println("Total Number of Columns : "+colNum);
int rowNum = sheet.getLastRowNum()+1;
System.out.println("Total Number of Rows : "+rowNum);
}
}