Java TCP Server receive Linux nc command

[Problem]

Linux 的 nc 指令(netcat)可透過 TCP/UDP 來傳送資料或訊息，但我目前無法使用 nc 或其他Linux指令來創造一個MultiThread TCP Server，僅能透過 nc 做一對一的傳送資料
如  Put Data into Remote HBase by using Linux Bash Script ，因此改用Java 寫一個MultiThreaded Server

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[Concept]

Reference:
- How to write RAW data to a file using Java? e.g same as: nc -l 8000 > capture.raw
- Multithreaded Server in Java
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[Code]

tcpserver.java  (Main Class)

package tcpserver;

public class tcpserver {
public static void main(String args[]){
MultiThreadedServer server = new MultiThreadedServer(9075);
System.out.println("***************************");
System.out.println("** TCP Collection Server **");
System.out.println("***************************");
new Thread(server).start();
}
}

MultiThreadedServer.java

package tcpserver;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class MultiThreadedServer implements Runnable{
protected int          serverPort   = 50200;
    protected ServerSocket serverSocket = null;
    protected boolean      isStopped    = false;
    protected Thread       runningThread= null;

    public MultiThreadedServer(int port){
        this.serverPort = port;
        System.out.println("System port setting : " + port);
    }

    public void run(){
     
    synchronized(this){
            this.runningThread = Thread.currentThread();  //Avoid another same Server(?)
        }
   
        openServerSocket();
     
        System.out.println("[INFO] Start Listening!");
        while(!isStopped()){
            Socket clientSocket = null;
            try {
                clientSocket = this.serverSocket.accept(); //wait client
            } catch (IOException e) {
                if(isStopped()) {
                    System.out.println("[ERROR] Server Stopped.") ;
                    return;
                }
                throw new RuntimeException("[ERROR] Error accepting client connection", e);
            }
            // Create a New Thread for client
            new Thread(
            new WorkerRunnable(clientSocket)
            ).start();
        }
        System.out.println("Server Stopped.") ;
    }


    private synchronized boolean isStopped() {
        return this.isStopped;
    }

    public synchronized void stop(){
        this.isStopped = true;
        try {
            this.serverSocket.close();
        } catch (IOException e) {
            throw new RuntimeException("Error closing server", e);
        }
    }

    private void openServerSocket() {
        try {
            this.serverSocket = new ServerSocket(this.serverPort);
            System.out.println("[INFO] Create a ServerSocket");
        } catch (IOException e) {
            throw new RuntimeException("Cannot open port 8080", e);
        }
    }
}

WorkerRunnable.java

package tcpserver;

import java.io.*;
import java.net.*;

public class WorkerRunnable implements Runnable{
protected Socket clientSocket = null;

public WorkerRunnable(Socket clientSocket){
this.clientSocket = clientSocket;
}

public void run(){
try{
byte[] buff = new byte[1024];
int bytes_read=0;
InputStream data = clientSocket.getInputStream(); // get input data
while(( bytes_read = data.read(buff)) != -1){     // print out
System.out.println(new String(buff));
//String str = new String(buff);
}
data.close();
}
catch(IOException e){
e.printStackTrace();
}
}
}

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[Result]