异常: 无法调用getLastRowNum(),因为”sheet”为空。

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英文:

Exception: Cannot invoke getLastRowNum()" as "sheet" is null

问题

我收到以下异常信息:

>java.lang.RuntimeException: java.lang.NullPointerException: 无法调用"org.apache.poi.xssf.usermodel.XSSFSheet.getLastRowNum()",因为"sheet"为空

以下是要翻译的代码部分:

public static Object[][] getTestDataFromExcel(String sheetName) {
    File excelFile = new File("C:\\Users\\abhis\\seleniumHybridFramework\\seleniumHybridFramework\\src\\main\\java\\com\\seleniumHybridFrameworkProject\\qa\\testdata\\seleniumHybridFrameworkProjectTestData.xlsx");
    XSSFWorkbook workbook = null;
    try {
        FileInputStream fisExcel = new FileInputStream(excelFile);
        workbook = new XSSFWorkbook(fisExcel);
    } catch (Throwable e) {
        e.printStackTrace();
    }

    XSSFSheet sheet = workbook.getSheet(sheetName);

    int rows = sheet.getLastRowNum();
    int cols = sheet.getRow(0).getLastCellNum();

    Object[][] data1 = new Object[rows][cols];

    for (int i = 0; i < rows; i++) {
        XSSFRow row = sheet.getRow(i + 1);
        
        for (int j = 0; j < cols; j++) {
            XSSFCell cell = row.getCell(j);
            CellType cellType = cell.getCellType();

            switch (cellType) {
                case STRING:
                    data1[i][j] = cell.getStringCellValue();
                    break;
                case NUMERIC:
                    data1[i][j] = Integer.toString((int) cell.getNumericCellValue());
                    break;
                case BOOLEAN:
                    data1[i][j] = cell.getBooleanCellValue();
                    break;
            }

        }

    }
    return data1;
}

XSSFSheet sheet = workbook.getSheet(sheetName)这一行中,getSheet被下划线标记,并显示建议,因为它可能会产生Nullpointer Exception,因为sheet可能为空。

我使用的是poi版本5.2.2、poi-ooxml版本5.2.2、poi-ooxml-schemas版本4.1.0。

我不知道为什么它无法识别工作簿中的工作表,而工作簿为空。

我尝试过File excelFile = new File(System.getProperty("user.dir")+"\\src\\main\\java\\com\\seleniumHybridFrameworkProject\\qa\\testdata\\seleniumHybridFrameworkProjectTestData.xlsx")。请查看一下。

英文:

I'm getting the following exception:

>java.lang.RuntimeException: java.lang.NullPointerException: Cannot invoke "org.apache.poi.xssf.usermodel.XSSFSheet.getLastRowNum()" as "sheet" is null

public static Object[][] getTestDataFromExcel(String sheetName) {
File excelFile = new File(&quot;C:\\Users\\abhis\\seleniumHybridFramework\\seleniumHybridFramework\\src\\main\\java\\com\\seleniumHybridFrameworkProject\\qa\\testdata\\seleniumHybridFrameworkProjectTestData.xlsx&quot;);
XSSFWorkbook workbook = null;
try {
FileInputStream fisExcel = new FileInputStream(excelFile);
workbook = new XSSFWorkbook(fisExcel);
} catch (Throwable e) {
e.printStackTrace();
}
XSSFSheet sheet = workbook.getSheet(sheetName);
int rows = sheet.getLastRowNum();
int cols = sheet.getRow(0).getLastCellNum();
Object[][] data1 = new Object[rows][cols];
for (int i = 0; i &lt; rows; i++) {
XSSFRow row = sheet.getRow(i + 1);
for (int j = 0; j &lt; cols; j++) {
XSSFCell cell = row.getCell(j);
CellType cellType = cell.getCellType();
switch (cellType) {
case STRING:
data1[i][j] = cell.getStringCellValue();
break;
case NUMERIC:
data1[i][j] = Integer.toString((int) cell.getNumericCellValue());
break;
case BOOLEAN:
data1[i][j] = cell.getBooleanCellValue();
break;
}
}
}
return data1;
}

Here in XSSFSheet sheet = workbook.getSheet(sheetName),
getSheet is underlined and showing suggestion that this can produce Nullpointer Exception becoz sheet may be is null.

I have poi version 5.2.2
poi-ooxml version 5.2.2
poi-ooxml-schemas 4.1.0

I don't know why it is not recognizing the sheet in a sheet path and workbook is null.

I have tried File excelFile = new File(System.getProperty(&quot;user.dir&quot;)+&quot;\\src\\main\\java\\com\\seleniumHybridFrameworkProject\\qa\\testdata\\seleniumHybridFrameworkProjectTestData.xlsx&quot;).

Please look at it.

答案1

得分: 2

错误信息

java.lang.RuntimeException: java.lang.NullPointerException: 无法调用 "org.apache.poi.xssf.usermodel.XSSFSheet.getLastRowNum()",因为 "sheet" 为 null

这说明 sheetnull

这可能是因为 XSSFWorkbook.getSheet 要么返回提供的名称的 XSSFSheet,要么如果不存在则返回 null。因此,在您的代码中,在 XSSFSheet sheet = workbook.getSheet(sheetName); 之后,如果工作簿中没有具有提供的 sheetName 的工作表,sheet 可能为 null。

就像对于 NullPointerException 一样,您必须检查是否得到了一个对象而不是 null

...
XSSFSheet sheet = workbook.getSheet(sheetName);
if (sheet != null) { 
 int rows = sheet.getLastRowNum();
 //... 处理工作表的操作
}
...

顺便说一下: poi-ooxml-schemas 4.1.0 不适用于 poi-ooxml 版本 5.2.2,因为混合使用不支持的 Apache POI 版本会导致意外错误。请参阅 faq-N10204

请查看 Apache POI - 组件概述。版本 5.2.2poi-ooxml 需要与之相同版本的 poi-ooxml-litepoi-ooxml-full,即版本 5.2.2,而不是版本 4.1.0

英文:

The error

java.lang.RuntimeException: java.lang.NullPointerException: Cannot invoke &quot;org.apache.poi.xssf.usermodel.XSSFSheet.getLastRowNum()&quot; as &quot;sheet&quot; is null

tells that sheet is null.

That's possible because XSSFWorkbook.getSheet either returns the
XSSFSheet with the name provided or null if it does not exist. So in your code after XSSFSheet sheet = workbook.getSheet(sheetName); sheet might be null if there is not a sheet having name given in sheetName in the workbook.

As always for NullPointerException you have to check whether you got an object and not null.

...
XSSFSheet sheet = workbook.getSheet(sheetName);
if (sheet != null) { 
int rows = sheet.getLastRowNum();
//... do what to do with sheet
}
...

Btw.: poi-ooxml-schemas 4.1.0 does not fit to poi-ooxml version 5.2.2 as mixing Apache POI versions is not supported and will lead to unexpected errors. See faq-N10204.

See Apache POI - Component Overview. The poi-ooxml of version 5.2.2 needs either poi-ooxml-lite of same version 5.2.2 or poi-ooxml-full of same version 5.2.2 but nothing of version 4.1.0.

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  • 本文由 发表于 2023年7月10日 14:44:14
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