Java--Socket 통신(클라이언트 서버 양방향)

import java.io.BufferedReader; 
import java.io.DataInputStream; 
import java.io.DataOutputStream; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.net.ServerSocket; 
import java.net.Socket; 
 
public class Server { 
 
  public static final int PORT = 8000;//    
 
  public static void main(String[] args) {  
    Server server = new Server();  
    server.init();  
  }  
 
  public void init() {  
    ServerSocket serverSocket = null; 
    try {  
      serverSocket = new ServerSocket(PORT);  
      while (true) {  
        Socket client = serverSocket.accept();  
        //   
        new Thread(new ReadHandlerThread(client)).start();  
        new Thread(new WriteHandlerThread(client)).start();  
      }  
    } catch (Exception e) {  
      e.printStackTrace();  
    } finally{ 
      try { 
        if(serverSocket != null){ 
          serverSocket.close(); 
        } 
      } catch (IOException e) { 
        e.printStackTrace(); 
      } 
    } 
  }  
}  
 
/* 
 *   
 */ 
class ReadHandlerThread implements Runnable{ 
  private Socket client; 
 
  public ReadHandlerThread(Socket client) { 
    this.client = client; 
  } 
 
  @Override 
  public void run() { 
    DataInputStream dis = null; 
    try{ 
      while(true){ 
        //   
        dis = new DataInputStream(client.getInputStream()); 
        String reciver = dis.readUTF(); 
        System.out.println(" :" + reciver);  
      } 
    }catch(Exception e){ 
      e.printStackTrace(); 
    }finally{ 
      try { 
        if(dis != null){ 
          dis.close(); 
        } 
        if(client != null){ 
          client = null; 
        } 
      } catch (IOException e) { 
        e.printStackTrace(); 
      } 
    } 
  } 
} 
 
/* 
 *   
 */ 
class WriteHandlerThread implements Runnable{ 
  private Socket client; 
 
  public WriteHandlerThread(Socket client) { 
    this.client = client; 
  } 
 
  @Override 
  public void run() { 
    DataOutputStream dos = null; 
    BufferedReader br = null; 
    try{ 
      while(true){ 
        //   
        dos = new DataOutputStream(client.getOutputStream());  
        System.out.print(" :\t");  
        //    
        br = new BufferedReader(new InputStreamReader(System.in)); 
        String send = br.readLine();  
        //  
        dos.writeUTF(send);  
      } 
    }catch(Exception e){ 
      e.printStackTrace(); 
    }finally{ 
      try { 
        if(dos != null){ 
          dos.close(); 
        } 
        if(br != null){ 
          br.close(); 
        } 
        if(client != null){ 
          client = null; 
        } 
      } catch (IOException e) { 
        e.printStackTrace(); 
      } 
    } 
  } 
} 

import java.io.BufferedReader; 
import java.io.DataInputStream; 
import java.io.DataOutputStream; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.net.Socket; 
 
public class Client { 
 
  public static final String IP = "localhost";//   
  public static final int PORT = 8000;//   
 
  public static void main(String[] args) {  
    handler();  
  } 
 
  private static void handler(){ 
    try { 
      // Socket，  
      Socket client = new Socket(IP, PORT); 
      // ， ，  
      new Thread(new ReadHandlerThread(client)).start(); 
      new Thread(new WriteHandlerThread(client)).start(); 
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
  } 
}  
 
/* 
 *   
 */ 
class ReadHandlerThread implements Runnable{ 
  private Socket client; 
 
  public ReadHandlerThread(Socket client) { 
    this.client = client; 
  } 
 
  @Override 
  public void run() { 
    DataInputStream dis = null; 
    try { 
      while(true){ 
        //   
        dis = new DataInputStream(client.getInputStream()); 
        String receive = dis.readUTF();   
        System.out.println(" : " + receive);  
      } 
    } catch (IOException e) { 
      e.printStackTrace(); 
    } finally{ 
      try { 
        if(dis != null){ 
          dis.close(); 
        } 
        if(client != null){ 
          client = null; 
        } 
      } catch (IOException e) { 
        e.printStackTrace(); 
      } 
    } 
  } 
} 
 
/* 
 *   
 */ 
class WriteHandlerThread implements Runnable{ 
  private Socket client; 
 
  public WriteHandlerThread(Socket client) { 
    this.client = client; 
  } 
 
  @Override 
  public void run() { 
    DataOutputStream dos = null; 
    BufferedReader br = null; 
    try { 
      while(true){ 
        //  
        dos = new DataOutputStream(client.getOutputStream()); 
        System.out.print(" : \t");  
        //  
        br = new BufferedReader(new InputStreamReader(System.in)); 
        String send = br.readLine();  
        //  
        dos.writeUTF(send);  
      } 
    } catch (IOException e) { 
      e.printStackTrace(); 
    } finally{ 
      try{ 
        if(dos != null){ 
          dos.close(); 
        } 
        if(br != null){ 
          br.close(); 
        } 
        if(client != null){ 
          client = null; 
        } 
      }catch(Exception e){ 
        e.printStackTrace(); 
      } 
    } 
  } 
}