Can someone please explain technically the functionality of the below code

Question

File src = new File(filePath);
FileInputStream fis = new FileInputStream(src);
XSSFWorkbook wb = new XSSFWorkbook(fis);
XSSFSheet sheet1 = wb.getSheetAt(0);

Why did they pass the src object to FileInputStream?

Why did they pass FileInputStream object to xssfworkbook?

Why they did'nt pass any objects for xssfsheet?

Have you read the appropriate documentation? I'd imagine that tells you what parameters the constructors and methods take. — jonrsharpe, Jan 19 '18 at 12:08
This is how workbooks and sheets are typically initiated in POI. The workbook needs a FileInputStream to read from, etc. Next step would be to call methods in sheet1 to read/write information. There are plenty of tutorials out there. — Stefan, Jan 19 '18 at 12:10

vadzim dvorak · Answer 1 · 2018-01-19T12:32:34.680

Just for fun. Key idea is reading docs and learning language

File src = new File(filePath);

Java File class represents the files and directory pathnames in an abstract manner. This class is used for creation of files and directories, file searching, file deletion, etc. https://www.tutorialspoint.com/java/java_file_class.htm

FileInputStream fis = new FileInputStream(src);

A FileInputStream obtains input bytes from a file in a file system. What files are available depends on the host environment. https://docs.oracle.com/javase/7/docs/api/java/io/FileInputStream.html

XSSFWorkbook wb = new XSSFWorkbook(fis);

High level representation of a SpreadsheetML workbook. This is the first object most users will construct whether they are reading or writing a workbook. It is also the top level object for creating new sheets/etc. https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFWorkbook.html

XSSFSheet sheet1 = wb.getSheetAt(0);

Get the XSSFSheet object at the given index. https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFWorkbook.html

score 0 · Accepted Answer · answered Jan 19 '18 at 12:20

Why did they pass the src object to FileInputStream?

Because FileInputStream will need a File to instantiate. src is an instance of File.

Why did they pass FileInputStream object to xssfworkbook?

Because XSSFWorkbook needs a FileInputStream to instantiate. fis is a FileInputStream.

Why they did'nt pass any objects for xssfsheet?

Because the sheet can be retrieved from wb using getSheetAt.

Can someone please explain technically the functionality of the below code

2 Answers2