Rahul/socket/read/pr2 (#6398)

* Making examples simple

* Changing variable names

* Modificatons in naming

* Read all data from server

* Adding seperate TestSocketRead class having live test

* Adding test case

* Changing test name to live tests

core-java-networking/src/main/java/com/baeldung/socket/read/Client.java

@@ -0,0 +1,37 @@
+package com.baeldung.socket.read;
+
+import java.net.*; 
+import java.io.*; 
+
+public class Client {
+
+    //Initialize socket, input and output stream
+    private Socket socket = null;
+    private DataInputStream in = null;
+    private DataOutputStream out = null;
+    
+    public void runClient(String ip, int port) {
+        try {
+            socket = new Socket(ip, port);
+            System.out.println("Connected to server ...");
+            in = new DataInputStream(System.in);
+            out = new DataOutputStream(socket.getOutputStream());
+        } catch(Exception e) {
+            e.printStackTrace();
+        }
+        char type = 's'; // s for string
+        int length = 29;
+        String data = "This is a string of length 29";
+        byte[] dataInBytes = data.getBytes();         
+        //Sending data in TLV format        
+        try {
+            out.writeChar(type);
+            out.writeInt(length);
+            out.write(dataInBytes);
+        } catch (IOException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
+    }
+
+}

core-java-networking/src/main/java/com/baeldung/socket/read/Server.java

@@ -0,0 +1,51 @@
+package com.baeldung.socket.read;
+
+import java.net.*; 
+import java.io.*; 
+
+public class Server {
+
+    //Socket and input stream
+    private Socket socket = null;
+    private ServerSocket server = null;
+    private DataInputStream in = null;
+    
+    public void runServer(int port) {
+        //Start the server and wait for connection
+        try {
+            server = new ServerSocket(port);
+            System.out.println("Server Started. Waiting for connection ...");
+            socket = server.accept();
+            System.out.println("Got connection from client.");
+            //Get input stream from socket variable and convert the same to DataInputStream
+            in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
+            //Read type and length of data
+            char dataType = in.readChar();
+            int length = in.readInt();
+            System.out.println("Type : "+dataType);
+            System.out.println("Lenght :"+length);
+            //Read String data in bytes
+            byte[] messageByte = new byte[length];
+            boolean end = false;
+            String dataString = "";
+            int totalBytesRead = 0;
+            //We need to run while loop, to read all data in that stream
+            while(!end) {
+                int currentBytesRead = in.read(messageByte);
+                totalBytesRead = currentBytesRead + totalBytesRead;
+                if(totalBytesRead <= length) {
+                    dataString += new String(messageByte,0,currentBytesRead);   
+                } else {
+                    dataString += new String(messageByte,0,length - totalBytesRead + currentBytesRead); 
+                }
+                if(dataString.length()>=length) {
+                    end = true;
+                }
+            }
+            System.out.println("Read "+length+" bytes of message from client. Message = "+dataString);;
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+}

core-java-networking/src/test/java/com/baeldung/socket/read/SocketReadAllDataLiveTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.socket.read;
+
+import java.util.concurrent.TimeUnit;
+import org.junit.jupiter.api.Test;
+
+public class SocketReadAllDataLiveTest {
+    
+    @Test
+    public void givenServerAndClient_whenClientSendsAndServerReceivesData_thenCorrect() {
+        //Run server in new thread
+        Runnable runnable1 = () -> { runServer(); };
+        Thread thread1 = new Thread(runnable1);
+        thread1.start();
+        //Wait for 10 seconds 
+        try {
+            TimeUnit.SECONDS.sleep(10);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        //Run client in a new thread
+        Runnable runnable2 = () -> { runClient(); };
+        Thread thread2 = new Thread(runnable2);
+        thread2.start();
+    }
+    
+    public static void runServer() {
+        //Run Server
+        Server server = new Server();
+        server.runServer(5555);
+    }
+    
+    public static void runClient() {
+        //Run Client
+        Client client = new Client();
+        client.runClient("127.0.0.1", 5555);
+    }
+}