Excel data reading (Apache POI) in Selenium Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Apache POI used for in Selenium Java testing?

Apache POI is a library used to read and write Microsoft Excel files in Selenium Java tests. It helps automate data-driven testing by accessing test data stored in Excel sheets.

beginner

Which Apache POI class is used to read an Excel workbook (.xlsx)?

The <code>XSSFWorkbook</code> class is used to read and write Excel workbooks with the .xlsx format.

beginner

How do you get a sheet from a workbook using Apache POI?

Use workbook.getSheet("SheetName") or workbook.getSheetAt(index) to get a specific sheet from the workbook.

intermediate

What is the correct way to read a cell value as a string in Apache POI?

Use cell.getStringCellValue() if the cell type is STRING. For other types, convert accordingly to avoid errors.

beginner

Why should you close the FileInputStream after reading an Excel file with Apache POI?

Closing the FileInputStream frees system resources and avoids file locks, ensuring other processes can access the file safely.

Which class do you use to open an Excel .xlsx file in Apache POI?

A XSSFWorkbook

B HSSFWorkbook

C WorkbookFactory

D ExcelReader

XSSFWorkbook is used for .xlsx files, while HSSFWorkbook is for older .xls files.

How do you get the number of rows in a sheet using Apache POI?

A sheet.getPhysicalNumberOfRows()

B sheet.getRowCount()

C sheet.getLastRowNum() + 1

D sheet.getRowNumber()

getPhysicalNumberOfRows() returns the count of physically defined rows.

What happens if you try to read a numeric cell with getStringCellValue()?

A Returns the number as a string

B Throws an exception

C Returns null

D Automatically converts to string

getStringCellValue() throws an exception if the cell type is not STRING.

Which method closes the workbook and releases resources in Apache POI?

A workbook.shutdown()

B workbook.dispose()

C workbook.release()

D workbook.close()

workbook.close() properly closes the workbook and frees resources.

Why is Apache POI preferred for Excel data reading in Selenium tests?

A It only reads CSV files

B It requires no coding

C It supports multiple Excel formats and is open source

D It is a paid tool

Apache POI supports .xls and .xlsx formats and is free to use.

Explain the steps to read data from an Excel file using Apache POI in Selenium Java.

Think about opening the file, accessing sheets, reading cells, and closing resources.

What are common pitfalls when reading Excel data with Apache POI and how to avoid them?

Consider errors from data types and resource management.

Practice

1. What is the main purpose of using Apache POI in Selenium Java testing?

easy

A. To read and write Excel files for test data management

B. To locate web elements on a webpage

C. To execute JavaScript code in the browser

D. To generate HTML reports for test results

Solution

1. Step 1: Understand Apache POI's role

   Apache POI is a library used to handle Microsoft Office files, especially Excel, in Java programs.

2. Step 2: Connect Apache POI with Selenium testing

   In Selenium tests, Apache POI helps read and write Excel files to manage test data efficiently.

3. Final Answer:

   To read and write Excel files for test data management -> Option A

4. Quick Check:

   Apache POI = Excel file handling [OK]

Hint: Apache POI = Excel data handling in Java tests [OK]

Common Mistakes:

• Confusing Apache POI with Selenium WebDriver functions
• Thinking Apache POI is for web element locating
• Assuming Apache POI generates test reports

2. Which of the following is the correct way to open an Excel workbook using Apache POI in Java?

easy

A. Workbook workbook = new Workbook("file.xlsx");

B. Workbook workbook = WorkbookFactory.create(new FileInputStream("file.xlsx"));

C. Workbook workbook = Workbook.open("file.xlsx");

D. Workbook workbook = new FileInputStream("file.xlsx");

Solution

1. Step 1: Identify correct Workbook creation method

   Apache POI uses WorkbookFactory.create(InputStream) to open Excel files safely.

2. Step 2: Check each option's syntax

   Workbook workbook = WorkbookFactory.create(new FileInputStream("file.xlsx")); correctly uses WorkbookFactory.create with FileInputStream. Others are invalid or incorrect constructors.

3. Final Answer:

   Workbook workbook = WorkbookFactory.create(new FileInputStream("file.xlsx")); -> Option B

4. Quick Check:

   Use WorkbookFactory.create with FileInputStream [OK]

Hint: Use WorkbookFactory.create with FileInputStream to open Excel [OK]

Common Mistakes:

• Trying to instantiate Workbook directly
• Using wrong constructors or methods
• Assigning FileInputStream to Workbook variable

3. Given the following code snippet, what will be printed if the Excel cell at row 0, column 1 contains the string "TestData"?

Workbook workbook = WorkbookFactory.create(new FileInputStream("data.xlsx"));
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(0);
Cell cell = row.getCell(1);
System.out.println(cell.getStringCellValue());
workbook.close();

medium

A. TestData

B. null

C. 0

D. Throws NullPointerException

Solution

1. Step 1: Access the correct cell value

   The code accesses row 0, cell 1, which contains the string "TestData".

2. Step 2: Print the string cell value

   Calling getStringCellValue() on that cell returns "TestData", which is printed.

3. Final Answer:

   TestData -> Option A

4. Quick Check:

   Cell value = "TestData" printed [OK]

Hint: getStringCellValue() returns cell text directly [OK]

Common Mistakes:

• Assuming cell is null and causes exception
• Using getNumericCellValue() on string cell
• Confusing row and column indexes

4. Identify the error in the following code snippet that reads an Excel file using Apache POI:

FileInputStream fis = new FileInputStream("data.xlsx");
Workbook workbook = WorkbookFactory.create(fis);
Sheet sheet = workbook.getSheetAt(0);
Row row = sheet.getRow(0);
Cell cell = row.getCell(0);
System.out.println(cell.getStringCellValue());
// Missing workbook.close()

medium

A. WorkbookFactory.create() cannot accept FileInputStream

B. getSheetAt(0) should be getSheet("Sheet1")

C. FileInputStream should be closed after use

D. getStringCellValue() cannot be called on numeric cells

Solution

1. Step 1: Check resource management

   The code opens FileInputStream but does not close it, which can cause resource leaks.

2. Step 2: Confirm correct usage of WorkbookFactory and methods

   WorkbookFactory.create accepts FileInputStream, getSheetAt(0) is valid, and getStringCellValue() is fine if cell is string.

3. Final Answer:

   FileInputStream should be closed after use -> Option C

4. Quick Check:

   Always close streams to avoid leaks [OK]

Hint: Always close FileInputStream and Workbook after use [OK]

Common Mistakes:

• Forgetting to close FileInputStream
• Assuming WorkbookFactory.create rejects streams
• Confusing sheet access methods

5. You want to read multiple rows from an Excel sheet and store the first column values into a List<String>. Which approach correctly reads all rows except the header row using Apache POI?

hard

A. Use a for loop from 1 to sheet.getPhysicalNumberOfRows(), get each row's cell(1) string value, add to list

B. Use a for loop from 0 to sheet.getLastRowNum(), get each row's cell(0) numeric value, add to list

C. Use a while loop with sheet.getPhysicalNumberOfRows(), get cell(1) string value, add to list

D. Use a for loop from 1 to sheet.getLastRowNum(), get each row's cell(0) string value, add to list

Solution

1. Step 1: Skip header row and loop through rows

   Start loop at 1 to skip header (row 0), loop until sheet.getLastRowNum() to cover all rows.

2. Step 2: Access first column cell and get string value

   Get cell at index 0 (first column), call getStringCellValue(), and add to list.

3. Final Answer:

   Use a for loop from 1 to sheet.getLastRowNum(), get each row's cell(0) string value, add to list -> Option D

4. Quick Check:

   Loop rows from 1, get cell(0) string values [OK]

Hint: Start loop at 1 to skip header, get cell(0) string values [OK]

Common Mistakes:

• Starting loop at 0 and including header
• Using wrong cell index (1 instead of 0)
• Using numeric value for string cells