commit Exercise_31_08

csv77 · csv77 · commit 04c947f4c14b · 2017-10-12T18:47:17.000+02:00
diff --git a/Chapter_31/exercise_31_08Server/Exercise_31_08Server.java b/Chapter_31/exercise_31_08Server/Exercise_31_08Server.java
@@ -0,0 +1,51 @@
+package exercise_31_08Server;
+
+import java.io.DataInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.ObjectOutputStream;
+import java.io.RandomAccessFile;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.ArrayList;
+
+public class Exercise_31_08Server {
+
+    public static void main(String[] args) {
+        try {
+            ServerSocket serverSocket = new ServerSocket(8000);
+            System.out.println("Server started!");
+            Socket socket = serverSocket.accept();
+            System.out.println("Client has connected.");
+            
+            DataInputStream inputFromClient = new DataInputStream(socket.getInputStream());
+            ObjectOutputStream outputToClient = new ObjectOutputStream(socket.getOutputStream());
+            
+            int count = inputFromClient.readInt();
+            System.out.println("Starting to read out the last " + count + " primes from file...");
+            
+            outputToClient.writeObject(getArrayList(count));
+            System.out.println("Array with the primes was sent.");
+        }
+        catch (IOException ex) {
+            ex.printStackTrace();
+        }
+    }
+    
+    public static ArrayList<Long> getArrayList(int countOfPrimes) {
+        ArrayList<Long> primes = new ArrayList<>();
+        try(RandomAccessFile raf = new RandomAccessFile("PrimeNumbers.dat", "r");){
+            raf.seek(raf.length() - 8 * countOfPrimes);
+            for(int i = 0; i < countOfPrimes; i++) {
+                primes.add(raf.readLong());
+            }
+        }
+        catch (FileNotFoundException ex) {
+            System.out.println("File not found");
+        }
+        catch (IOException ex) {
+            System.out.println("IOException");
+        }
+        return primes;
+    }
+}
diff --git a/Chapter_31/exercise_31_08_Client/Exercise_31_08_Client.java b/Chapter_31/exercise_31_08_Client/Exercise_31_08_Client.java
@@ -0,0 +1,46 @@
+package exercise_31_08_Client;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.net.Socket;
+import java.util.ArrayList;
+import java.util.Scanner;
+
+public class Exercise_31_08_Client {
+
+    public static void main(String[] args) {
+        System.out.println("Enter a count to get the get the last x pcs of prime numbers from PrimeNumbers.dat: ");
+        int count = new Scanner(System.in).nextInt();
+        ArrayList<Long> primes;
+        
+        try {
+            Socket socket = new Socket("localhost", 8000);
+            ObjectInputStream inputFromServer = new ObjectInputStream(socket.getInputStream());
+            DataOutputStream outputToServer = new DataOutputStream(socket.getOutputStream());
+            outputToServer.writeInt(count);
+            System.out.println("Count was sent to server.");
+            
+            primes = (ArrayList<Long>)(inputFromServer.readObject());
+            
+            int i = 1;
+            System.out.println("The last " + count + " primes from PrimeNumbers.dat are: ");
+            for(long number : primes) {
+                if(i % 10 == 0) {
+                    System.out.println(number);
+                }
+                else {
+                    System.out.print(number + " ");
+                }
+                i++;
+            }
+            System.out.println();
+        }
+        catch (IOException ex) {
+            ex.printStackTrace();
+        }
+        catch (ClassNotFoundException ex) {
+            ex.printStackTrace();
+        }
+    }
+}
