Java socket 바이트 흐름 예제 해석

package com.yuan.socket;

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

/**
 * Created by YUAN on 2016-09-17.
 */
public class TalkServer4Byte {
  
  private ServerSocket server;
  private int port = 5020;

  public TalkServer4Byte() {
    try {
      server = new ServerSocket(port);
    } catch (IOException e) {
    }
  }

  public void talk() {
    System.out.println(" ：" + port);
    Socket socket = null;
    while (true) {
      try {
        //  ， 
        socket = server.accept();
        System.out.println(" ：" + socket.getRemoteSocketAddress());

        //  BufferedReader （ ）
        BufferedInputStream bis = new BufferedInputStream(
            socket.getInputStream());

        DataInputStream dis = new DataInputStream(bis);
        byte[] bytes = new byte[1]; //  byte
        String ret = "";
        while (dis.read(bytes) != -1) {
          ret += bytesToHexString(bytes) + " ";
          if (dis.available() == 0) { // 
            doSomething(ret);
          }
        }

      } catch (IOException e) {
        System.out.println(e.getMessage());
      } finally {
        try {
          socket.close();
        } catch (IOException e) {
          System.out.println(e.getMessage());
        }
      }
    }

  }
  
  public static void doSomething(String ret) {
    System.out.println(ret);
  }

  public static String bytesToHexString(byte[] src) {
    StringBuilder stringBuilder = new StringBuilder("");
    if (src == null || src.length <= 0) {
      return null;
    }
    for (int i = 0; i < src.length; i++) {
      int v = src[i] & 0xFF;
      String hv = Integer.toHexString(v);
      if (hv.length() < 2) {
        stringBuilder.append(0);
      }
      stringBuilder.append(hv);
    }
    return stringBuilder.toString();
  }

  public static String BytesHexString(byte[] b) {
    String ret = "";
    for (int i = 0; i < b.length; i++) {
      String hex = Integer.toHexString(b[i] & 0xFF);
      if (hex.length() == 1) {
        hex = '0' + hex;
      }
      ret += hex.toUpperCase();
    }
    return ret;
  }

  public static void main(String[] args) {
    TalkServer4Byte server = new TalkServer4Byte();
    server.talk();
  }
}

package com.yuan.socket;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;

/**
 * Created by YUAN on 2016-09-17.
 */
public class TalkClient4Byte {
  
  private Socket socket;
  private SocketAddress address;

  public TalkClient4Byte() {
    try {
      socket = new Socket();
      address = new InetSocketAddress("127.0.0.1", 5020);
      socket.connect(address, 1000);
    } catch (IOException e) {
      e.printStackTrace();
    }

  }

  public void talk() {

    try {

      // DataInputStream 
      InputStream os = new DataInputStream(System.in);
      
      byte [] b = new byte[1];
      DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
      while (-1 != os.read(b)) {
        dos.write(b); //  
      }
      
      dos.flush();
      dos.close();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      try {
        socket.close();
      } catch (IOException e) {

      }
    }
  }

  public static void main(String[] args) {
    TalkClient4Byte client = new TalkClient4Byte();
    client.talk();
  }

}