How to write array to OutputStream in Java?

java, outputstream, sockets

Solution

Use java.io.DataOutputStream / DataInputStream pair, they know how to read ints. Send info as a packet of length + random numbers.

sender

Socket sock = new Socket("localhost", 8181);
DataOutputStream out = new DataOutputStream(sock.getOutputStream());
out.writeInt(len);
for(int i = 0; i < len; i++) {
      out.writeInt(randomGenerator.nextInt(35))
...

receiver

 DataInputStream in = new DataInputStream(sock.getInputStream());
 int len = in.readInt();
 for(int i = 0; i < len; i++) {
      int next = in.readInt();
 ...

Problem

I want to send more than one random value though `Socket`. I think array is the best way to send them. But I don't know how to write an array to Socket `OutputStream`? My Java class: import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.Socket; import java.io.*; import java.util.Random; ``` public class NodeCommunicator { public static void main(String[] args) { try { Socket nodejs = new Socket("localhost", 8181); Random randomGenerator = new Random(); for (int idx = 1; idx <= 1000; ++idx){ Thread.sleep(500); int randomInt = randomGenerator.nextInt(35); sendMessage(nodejs, randomInt + " "); System.out.println(randomInt); } while(true){ Thread.sleep(1000); } } catch (Exception e) { System.out.println("Connection terminated..Closing Java Client"); System.out.println("Error :- "+e); } } public static void sendMessage(Socket s, String message) throws IOException { s.getOutputStream().write(message.getBytes("UTF-8")); s.getOutputStream().flush(); } } ```

Original source