Java FileDescriptor Example
November 18, 2023
java.io.FileDescriptor represents an open file or socket. It is used with FileInputStream and FileOutputStream. Two instances of FileOutputStream or FileInputStream can communicate using FileDescriptor.
Example-1
FileDescriptorDemoOne.java
package com.cp.io;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
public class FileDescriptorDemoOne {
public static void main(String[] args) throws IOException {
File file = new File("D:/test.txt");
FileOutputStream fos1 = new FileOutputStream(file);
FileDescriptor fd = fos1.getFD();
//passing FileDescriptor to another FileOutputStream
FileOutputStream fos2 = new FileOutputStream(fd);
fos2.write("Hello World!".getBytes());
fos1.close();
fos2.close();
}
}
FileDescriptor. FileOutputStream can contain FileDescriptor. In the example we have created an instance of FileOutputStream and then got FileDescriptor. Pass the the FileDescriptor instance to another FileOutputStream instance. What we get is that the second FileOutputStream instance gets the context of first FileOutputStream.
Example-2
Find the example ofFileDescriptor with FileInputStream.
FileDescriptorDemoTwo.java
package com.cp.io;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.IOException;
public class FileDescriptorDemoTwo {
public static void main(String[] a) throws IOException {
File file = new File("D:/test.txt");
FileInputStream fis1 = new FileInputStream(file);
FileDescriptor fd = fis1.getFD();
//passing FileDescriptor to another FileInputStream
FileInputStream fis2 = new FileInputStream(fd);
int i=0;
while((i=fis2.read())!=-1){
System.out.print((char)i);
}
fis1.close();
fis2.close();
}
}
