Ведь подразумевается, что файл уже зашифрован ?
package com.javarush.task.task18.task1826;
import java.io.*;
import java.util.Base64;
/*
Шифровка
*/
public class Solution {
public static void main(String[] args) throws IOException {
FileInputStream inputStream = new FileInputStream(args[1]);
FileOutputStream outputStream = new FileOutputStream(args[2]);
switch (args[0]){
case "-e":
Base64.Encoder encoder=Base64.getEncoder();
byte[] ebytes = encoder.encode(args[1].getBytes());
outputStream.write(ebytes);
inputStream.close();
outputStream.close();
break;
case "-d":
Base64.Decoder dec = Base64.getDecoder();
byte[] decbytes = dec.decode(args[1].getBytes());
outputStream.write(decbytes);
outputStream.close();
inputStream.close();
break;
}
}
}