[Projekt] Useradmin.java hinzugefügt

Signed-off-by: Jim Martens <github@2martens.de>

projekt/Useradmin.java

@@ -0,0 +1,64 @@
+import java.io.*;
+import java.nio.file.*;
+import java.nio.charset.*;
+import java.util.List;
+
+class Useradmin {
+	
+	public static void main(String[] args) {
+		if (args.length == 2) {
+			String method = args[0];
+			String username = args[1];
+			Console console = System.console();
+			System.out.println("Enter the password:");
+			String password = console.readLine();
+			Useradmin useradmin = new Useradmin();
+			switch (method) {
+				case "addUser":
+					useradmin.addUser(username, password.toCharArray());
+					break;
+				case "checkUser":
+					boolean result = useradmin.checkUser(username, password.toCharArray());
+					System.out.println("Does the user " + username + " exist? " + result);
+					break;
+			}
+		}
+		else {
+			System.out.println("Please provide 2 parameters: addUser|checkUser <username>");
+		}
+	}
+
+	public void addUser(String username, char[] password) {
+		char[] hashedPW = password;
+		String hashedPWString = String.valueOf(hashedPW);
+		String format = username + ":" + hashedPWString;
+		try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("passwords.txt", true)))) {
+		    out.println(format);
+		    System.out.println("User has been created");
+		} catch (IOException e) {
+		    //exception handling left as an exercise for the reader
+		}
+	}
+
+	public boolean checkUser(String username, char[] password) {
+		char[] hashedPW = password;
+		String hashedPWString = String.valueOf(hashedPW);
+		boolean result = false;
+		try {
+			List<String> passwords = Files.readAllLines(Paths.get("passwords.txt"), StandardCharsets.UTF_8);
+
+			for (String uidPW : passwords) {
+				int indexOfColon = uidPW.indexOf(':');
+				String user = uidPW.substring(0, indexOfColon);
+				String pw = uidPW.substring(indexOfColon + 1);
+				if (user.equals(username) && pw.equals(hashedPWString)) {
+					result = true;
+				}
+			}
+		}
+		catch (IOException ioe) {
+
+		}
+		return result;
+	}
+}