aufgabe 3

praktikum-5/.gitignore

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+build
+result

praktikum-5/aufgabe1/InternetAdresse.java

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+// DK, 18.11.2022
+
+import java.net.UnknownHostException;
+import java.net.InetAddress;
+
+public class InternetAdresse {
+    public static void main( String args[] ) {
+        try {
+            InetAddress iaddr1 = InetAddress.getByName("www.fh-dortmund.de");
+            InetAddress iaddr2 = InetAddress.getLocalHost();
+            InetAddress iaddr3 = InetAddress.getByName("localhost");
+            System.out.println(iaddr1.getHostName() + ": " + iaddr1.getHostAddress());
+            System.out.println(iaddr2.getHostName() + ": " + iaddr2.getHostAddress());
+            System.out.println(iaddr3.getHostName() + ": " + iaddr3.getHostAddress());
+            System.out.println();
+
+            byte[] ip = iaddr3.getAddress();
+            for(int i = 0; i < ip.length; i++) {
+                System.out.println(i + ": " + ip[i]);
+            }
+            System.out.println();
+
+            InetAddress[] iaddr4 = InetAddress.getAllByName("www.adeso.de");
+            for (int i = 0; i < iaddr4.length; i++) {
+                System.out.println(i + ": " + iaddr4[i].getHostName() + ": " + iaddr4[i].getHostAddress());
+            }
+        }
+        catch (UnknownHostException e) {
+            System.out.println( "Host nicht bekannt" );
+        }
+    }
+}

praktikum-5/aufgabe2/MACAdresse.java

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+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.net.SocketException;
+import java.net.NetworkInterface;
+
+public class MACAdresse {
+    public static void main( String args[] ) {
+        try {
+            InetAddress iaddr1 = InetAddress.getByName("www.fh-dortmund.de");
+            InetAddress iaddr2 = InetAddress.getLocalHost();
+            InetAddress iaddr3 = InetAddress.getByName("localhost");
+            System.out.println(iaddr1.getHostName() + ": " + iaddr1.getHostAddress());
+            System.out.println(iaddr2.getHostName() + ": " + iaddr2.getHostAddress());
+            System.out.println(iaddr3.getHostName() + ": " + iaddr3.getHostAddress());
+            System.out.println();
+
+            byte[] ip = iaddr3.getAddress();
+            for(int i = 0; i < ip.length; i++) {
+                System.out.println(i + ": " + ip[i]);
+            }
+            System.out.println();
+
+            InetAddress[] iaddr4 = InetAddress.getAllByName("www.adeso.de");
+            for (int i = 0; i < iaddr4.length; i++) {
+                System.out.println(i + ": " + iaddr4[i].getHostName() + ": " + iaddr4[i].getHostAddress());
+            }
+            System.out.println();
+
+            var net = NetworkInterface.getByName("eth0");
+            byte[] macAdress = net.getHardwareAddress();
+            for (int i = 0; i < macAdress.length; i++) {
+                System.out.println(i + ": " + macAdress[i]);
+            }
+        }
+        catch (UnknownHostException e) {
+            System.out.println( "Host nicht bekannt: " + e );
+        }
+        catch (SocketException e) {
+            System.out.println("Socket exception: " + e);
+        }
+    }
+
+}

praktikum-5/aufgabe3/Client.java

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+package aufgabe3;
+
+import java.net.Socket;
+import java.net.UnknownHostException;
+import java.util.Scanner;
+import java.io.OutputStreamWriter;
+import java.io.IOException;
+
+public class Client {
+    private int port;
+
+    public Client(int port) {
+        this.port = port;
+    }
+
+    public void send(String msg) throws IOException {
+        var socket = new Socket("localhost", port);
+        var out = socket.getOutputStream();
+        var writer = new OutputStreamWriter(out);
+        writer.write(msg);
+        writer.flush();
+        writer.close();
+    }
+
+    public static void main(String[] args) {
+        try {
+            int port = 4711;
+            var client = new Client(port);
+            var reader = new Scanner(System.in);
+            while (true) {
+                var msg = reader.nextLine();
+                client.send(msg);
+            }
+        } catch (Exception e) {
+            System.out.println(e);
+        }
+    }
+}

praktikum-5/aufgabe3/Server.java

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+package aufgabe3;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.ServerSocket;
+import java.net.Socket;
+
+public class Server {
+    private ServerSocket socket;
+
+    public Server(ServerSocket socket) {
+        this.socket = socket;
+    }
+
+    public String receive() throws IOException {
+        var client = socket.accept();
+        var in = client.getInputStream();
+        var reader = new InputStreamReader(in);
+        var result = "";
+        var curr = reader.read();
+        while (curr != -1) {
+            result += (char)curr;
+            curr = reader.read();
+        }
+        return result;
+    }
+
+    public static void main(String[] args) {
+        try {
+            int port = 4711;
+            var socket = new ServerSocket(port);
+            var server = new Server(socket);
+            System.out.println("Listening on port " + port);
+            while (true) {
+                var msg = server.receive();
+                System.out.println("Received message: " + msg);
+            }
+        } catch (Exception e) {
+            System.out.println(e);
+        }
+    }
+}

praktikum-5/build.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project name="Praktikum5" default="run" basedir=".">
+
+    <property name="src.dir" value="."/>
+    <property name="build.dir" value="build"/>
+    <property name="classes.dir" value="${build.dir}/classes"/>
+    <property name="main-class" value=""/>
+
+    <target name="clean">
+        <delete dir="${build.dir}"/>
+    </target>
+
+    <target name="compile">
+        <mkdir dir="${classes.dir}"/>
+        <javac srcdir="${src.dir}" destdir="${classes.dir}"
+               includeantruntime="false" debug="true">
+            <compilerarg value="-Xlint:unchecked"/>
+        </javac>
+    </target>
+
+    <target name="run" depends="compile">
+        <java classname="${main-class}" classpath="${classes.dir}" fork="true"/>
+    </target>
+
+</project>

praktikum-5/shell.nix

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+with import <nixpkgs> {};
+  mkShell {
+    packages = [
+      openjdk
+      ant
+      astyle
+      jdt-language-server
+    ];
+
+    shellHook = ''
+      echo "Usage Example: ant run -Dmain-class=aufgabe3.Server"
+    '';
+  }