In Java, we can copy the contents of one file to another file. This can be done by the FileInputStream and FileOutputStream classes.
FileInputStream Class
It is a byte input stream class which helps in reading the bytes from a file. It provides different methods to read the data from a file.
FileInputStream fin = new FileInputStream(filename);
This creates a FileInputStream object fin given a filename to it from where it will copy the content or do read operation.
Methods used:
1. read(): This method is used to read a byte of data. It returns that byte as an integer value or return -1 if the end of file is reached.
2. close(): This method is used to close the FileInputStream.
FileOutputStream Class
It is a byte output stream class which helps in writing the bytes to a file. It provides different functions to write the data to a file.
FileOutputStream fout = new FileOutputStream(filename);
This creates a FileOutputStream object fout given a filename to which it will write the read content.
Methods used:
1. write(): This method is used to write a byte of data to the FileOutputStream.
2. close(): This method is used to close the FileInputStream.
File Class
File f = new File(filename);
This creates an File object named f, given a string object which is the file name or location path of that file which is to be accessed.
Note: If the filename given here does not exist, then the File class will create a new file of that name.
Example:
Java
// Java program to copy content from// one file to another import java.io.*;import java.util.*; public class CopyFromFileaToFileb { public static void copyContent(File a, File b) throws Exception { FileInputStream in = new FileInputStream(a); FileOutputStream out = new FileOutputStream(b); try { int n; // read() function to read the // byte of data while ((n = in.read()) != -1) { // write() function to write // the byte of data out.write(n); } } finally { if (in != null) { // close() function to close the // stream in.close(); } // close() function to close // the stream if (out != null) { out.close(); } } System.out.println("File Copied"); } public static void main(String[] args) throws Exception { Scanner sc = new Scanner(System.in); // get the source file name System.out.println( "Enter the source filename from where you have to read/copy :"); String a = sc.nextLine(); // source file File x = new File(a); // get the destination file name System.out.println( "Enter the destination filename where you have to write/paste :"); String b = sc.nextLine(); // destination file File y = new File(b); // method called to copy the // contents from x to y copyContent(x, y); }} |
Output
Enter the source filename from where you have to read/copy : sourcefile.txt Enter the destination filename where you have to write/paste : destinationfile.txt File Copied
Source File
Source File
Destination File
Destination File
