获得使用Apache POI最后一行值

Question

获取显示java.lang.NullPointerException当我试图让使用getLastRowNum（）函数一个Excel工作表最后一行的值。

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;   
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class Excel{
public static File file;
public static FileInputStream input;
public static FileOutputStream output;
public static HSSFWorkbook book;     
public static HSSFSheet sheet;
public static int value;
public Excel(String path) {


    try {
        file= new File(path);//creating file//
        input=new FileInputStream(file);
        book=new HSSFWorkbook(input);           
        sheet=book.getSheetAt(0);                
        output=new FileOutputStream(file);          
    }
    catch(Exception e) {
        e.getMessage();
    }
        }
public static void readData() {
    int value =sheet.getLastRowNum();//trying to get the last row value//
    System.out.println(value);

}
}

驱动程序类：

      public class ExcelTest {
      public static void main(String[] args) {
      Excel excel = new Excel("C:/Users/HOME/Desktop/Sample.xlsx");
      Excel.readData();     
}
} 

请对这一问题有所帮助。

Answer 1

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;


public class readExcel {
    public static void main(String[] args) throws Exception{

              readData("path to sample.xlsx");
    }
    public static void readData(String path) throws FileNotFoundException, IOException{
            //getting xlsx file from path
            FileInputStream file = new FileInputStream(new File(path));
         XSSFWorkbook workbook = new XSSFWorkbook(file);

        //pointing to particlar workbook
            XSSFSheet spreadsheet = workbook.getSheetAt(0);
            //getting no: of rows
            int value=spreadsheet.getLastRowNum()+1;
            System.out.println("total rows:"+value);

            }

}

请与POI-3.9 JAR文件一起添加的dom4j-1.6.1，XMLBeans的-2.3.0罐