vba 从 Excel Sheet 读取数据时得到 NullpointerException
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While reading data from Excel Sheet got NullpointerException
提问by Shantanu Nandan
I am trying to read data from a excel sheet but getting NullPointerException every time when reading data at the cell index =6. Put while(value != null) to avoid null values but still got the exception without any output.
I am putting the screen shot of excel sheet from where i am trying to get data. 
我试图从 Excel 工作表中读取数据，但每次在单元格索引 =6 处读取数据时都会获得 NullPointerException。放置 while(value != null) 以避免空值，但仍然得到没有任何输出的异常。我正在将 excel 表的屏幕截图从我试图获取数据的地方放上。
Code-
package com.selenium;
import java.io.FileInputStream;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.usermodel.WorkbookFactory;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;
import java.io.IOException;
public class Exxcel {
public static void main(String[] args) throws Exception,NullPointerException{
//WebDriver driver= new FirefoxDriver();
//WebElement wb;
try{
FileInputStream file= new FileInputStream("C:\Documents and Settings\OMEGA\Desktop\Test Planning And Documents\Automation Data.xlsx");
Workbook data=WorkbookFactory.create(file);
Sheet sheet=data.getSheet("Sheet1");
for(int i=1;i<=sheet.getLastRowNum();i++){
Row row= sheet.getRow(i);
int j=0;
String value=row.getCell(j).getStringCellValue();
while(value != null){
System.out.println(value);
}//while
while(value == null){
j++;
}
}//for
/*while(j1==9){
String value=row.getCell(j1).getStringCellValue();
System.out.println(value);
}//while2
*/
}catch(NullPointerException n){n.printStackTrace();
System.out.println("Null");
}// catch
}//main
}//class
StackTrace-
Null
java.lang.NullPointerException
at com.selenium.Exxcel.main(Exxcel.java:22)
回答by Eran
It's not enough to check that row.getCell(j).getStringCellValue() != null. You should check that row.getCell(j) != null.
仅仅检查它是不够的row.getCell(j).getStringCellValue() != null。你应该检查一下row.getCell(j) != null。
In addition, your while loops makes no sense :
此外，您的 while 循环毫无意义：
The first one will either do nothing or print value forever (since you are not changing value inside the loop).
第一个要么什么都不做，要么永远打印值（因为你没有在循环内改变值）。
while(value != null) {
System.out.println(value);
}//while
The second one will either do nothing or increment j forever (since you are not changing value inside the loop).
第二个要么什么都不做，要么永远增加 j （因为你没有改变循环内的值）。
while(value == null) {
j++;
}
I suggest you replace them with the following code :
我建议你用以下代码替换它们：
Row row = sheet.getRow(i);
if (row != null) {
for (int j = 0; j < row.getLastCellNum(); j++) {
if (row.getCell(j) != null) {
if (row.getCell(j).getCellType() == CELL_TYPE_STRING) {
String value=row.getCell(j).getStringCellValue();
if(value != null) {
System.out.println(value);
}
}
}
}
}
