자바 socket 연결 및 데이터 전송 및 수신

/**
 * 
 */
package socketTest2;


import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static final int PORT = 12345;//         
    
    public static void main(String[] args) {  
        System.out.println("     ...
");  
        Server server = new Server();  
        server.init();  
    }  
  
    public void init() {  
        try {  
            ServerSocket serverSocket = new ServerSocket(PORT);  
            while (true) {  
                //      ,                  
                Socket client = serverSocket.accept();  
                //         
                new HandlerThread(client);  
            }  
        } catch (Exception e) {  
            System.out.println("     : " + e.getMessage());  
        }  
    }  
  
    private class HandlerThread implements Runnable {  
        private Socket socket;  
        public HandlerThread(Socket client) {  
            socket = client;  
            new Thread(this).start();  
        }  
  
        public void run() {  
            try {  
                //          
                DataInputStream input = new DataInputStream(socket.getInputStream());
                String clientInputStr = input.readUTF();//                  ,     EOFException
                //          
                System.out.println("         :" + clientInputStr);  
  
                //           
                DataOutputStream out = new DataOutputStream(socket.getOutputStream());  
                System.out.print("   :\t");  
                //            
                String s = new BufferedReader(new InputStreamReader(System.in)).readLine();  
                out.writeUTF(s);  
                
                out.close();  
                input.close();  
            } catch (Exception e) {  
                System.out.println("    run   : " + e.getMessage());  
            } finally {  
                if (socket != null) {  
                    try {  
                        socket.close();  
                    } catch (Exception e) {  
                        socket = null;  
                        System.out.println("    finally   :" + e.getMessage());  
                    }  
                }  
            } 
        }  
    }  
}  

/**
 * 
 */
package socketTest2;


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_ADDR = "localhost";//      
    public static final int PORT = 12345;//        
    
    public static void main(String[] args) {  
        System.out.println("     ...");  
        System.out.println("            \"OK\"    ,       
"); 
        while (true) {  
            Socket socket = null;
            try {
                //                         
                socket = new Socket(IP_ADDR, PORT);  
                  
                //          
                DataInputStream input = new DataInputStream(socket.getInputStream());  
                //           
                DataOutputStream out = new DataOutputStream(socket.getOutputStream());  
                System.out.print("   : \t");  
                String str = new BufferedReader(new InputStreamReader(System.in)).readLine();  
                out.writeUTF(str);  
                  
                String ret = input.readUTF();   
                System.out.println("          : " + ret);  
                //      "OK"        
                if ("OK".equals(ret)) {  
                    System.out.println("        ");  
                    Thread.sleep(500);  
                    break;  
                }  
                
                out.close();
                input.close();
            } catch (Exception e) {
                System.out.println("     :" + e.getMessage()); 
            } finally {
                if (socket != null) {
                    try {
                        socket.close();
                        System.out.println("socket is closed");
                    } catch (IOException e) {
                        socket = null; 
                        System.out.println("    finally   :" + e.getMessage()); 
                    }
                }
            }
        }  
    }  
}