Java如何利用POI读取Excel行数

package test; 
  
import java.io.FileInputStream; 
  
import org.apache.poi.hssf.usermodel.HSSFWorkbook; 
import org.apache.poi.hssf.util.CellReference; 
import org.apache.poi.ss.usermodel.Cell; 
import org.apache.poi.ss.usermodel.Row; 
import org.apache.poi.ss.usermodel.Sheet; 
import org.apache.poi.ss.usermodel.Workbook; 
  
public class test2{ 
  public static void main(String[] args) { 
    Workbook wb = null; 
    try { 
      wb = new HSSFWorkbook(new FileInputStream("E:\\Workspaces\\testdata\\仓库数据.xls")); 
    } catch (Exception e) { 
       // 
    } 
    Sheet sheet = wb.getSheetAt(0); 
    CellReference cellReference = new CellReference("A4"); 
    boolean flag = false; 
    System.out.println("总行数："+(sheet.getLastRowNum()+1)); 
    for (int i = cellReference.getRow(); i <= sheet.getLastRowNum();) { 
      Row r = sheet.getRow(i); 
      if(r == null){ 
        // 如果是空行（即没有任何数据、格式），直接把它以下的数据往上移动 
        sheet.shiftRows(i+1, sheet.getLastRowNum(),-1); 
        continue; 
      } 
      flag = false; 
      for(Cell c:r){ 
        if(c.getCellType() != Cell.CELL_TYPE_BLANK){ 
          flag = true; 
          break; 
        } 
      } 
      if(flag){ 
        i++; 
        continue; 
      } 
      else{//如果是空白行（即可能没有数据，但是有一定格式） 
        if(i == sheet.getLastRowNum())//如果到了最后一行，直接将那一行remove掉 
          sheet.removeRow(r); 
        else//如果还没到最后一行，则数据往上移一行 
          sheet.shiftRows(i+1, sheet.getLastRowNum(),-1); 
      } 
    } 
    System.out.println("总行数："+(sheet.getLastRowNum()+1)); 
  } 
    
}