Java.io.FileInputStream.getFD() method is a part of Java.io.FileInputStream class. This method will return the FileDescriptor object associated with the file input stream.
- getFD() method is declared as final that means getFD() cannot be overridden in the subclasses
- FileDescriptor object that we will get using getFD() method will represent the connection to the actual file in the file system
- getFD() method might throw IOException.
Syntax:
public final FileDescriptor getFD() throws IOException
Return Type: getFD() method will return the instance of FileDescriptor associated with this FileInputStream.
Exception: getFD() method might throw IOException if any Input/output exception raises.
How to invoke getFD() method?
Step 1: First, we have to create an instance of Java.io.FileInputStream class
FileInputStream fileInputStream =new FileInputStream("tmp.txt");
Step 2: To get the instance of FileDescriptor associated with this fileInputStream, we will invoke the getFD() method
FileDescriptor fileDescriptor =fileInputStream.getFD();
Example: Java Program to get an instance of FileDescriptor and then to check it is valid or not
In the below program, we will
- use Java.io.FileInputStream.getFD() method to get the object of FileDescriptor
- use FileDescriptor valid() method to check if the instance of the file descriptor is valid or not
Java
// Java Program to get an instance// of FileDescriptor and then to// check it is valid or not import java.io.*;class GFG { public static void main(String[] args) { try { // create instance of FileInputStream class // user should change name of the file FileInputStream fileInputStream = new FileInputStream( // if the specified file does not exist if (fileInputStream == null) { System.out.println( "Cannot find the specified file"); return; } // to get the object of FileDescriptor for // this specified fileInputStream FileDescriptor fileDescriptor = fileInputStream.getFD(); // check if the fileDescriptor is valid or not // using it's valid method // valid() will return true if valid else false System.out.println("Is FileDescriptor valid : " + fileDescriptor.valid()); // will close the file input stream and releases // any system resources associated with the // stream. fileInputStream.close(); } catch (Exception exception) { System.out.println(exception.getMessage()); } }} |
Output:
Is FileDescriptor valid : true
tmp.txt
Note: The programs will run on an online IDE. Please use an offline IDE and change the Name of the file according to your need.
