Socket網絡協議之一

客戶端：Socket一般也稱作」套接字「，用於描述IP地址和端口，廢話很少說，它就是網絡通訊過程當中端點的抽象表示。值得一提的是，Java在包java.net中提供了兩個類Socket和ServerSocket，分別用來表示雙向鏈接的客戶端和服務端。這是兩個封裝得很是好的類，使用起來很方便！

    下面將首先建立一個SocketServer的類做爲服務端以下，該服務端實現了多線程機制，能夠在特定端口處監聽多個客戶請求，一旦有客戶請求，Server老是會建立一個服務純種來服務新來的客戶，而本身繼續監聽。程序中accept()是一個阻塞函數，所謂阻塞性方法就是說該方法被調用後將等待客戶的請求，直到有一個客戶啓動並請求鏈接到相同的端口，而後accept()返回一個對應於客戶的Socket。這時，客戶方和服務方都創建了用於通訊的Socket，接下來就是由各個Socket分別打開各自的輸入、輸出流。

• SocketServer類，服務器實現：

package server;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
public class SocketServer {
 ServerSocket sever;   
 
 public  SocketServer(int port){
        try{
            sever = new ServerSocket(port);
        }catch(IOException e){
            e.printStackTrace();
        }
    }
    
    public void beginListen(){
        while(true){
            try{
                final Socket socket = sever.accept();
                
                new Thread(new Runnable(){
                    public void run(){
                        BufferedReader in;
                        try{
                            in = new BufferedReader(new InputStreamReader(socket.getInputStream(),"UTF-8"));
                            PrintWriter out = new PrintWriter(socket.getOutputStream());
                            while (!socket.isClosed()){
                                String str;
                                str = in.readLine();
                                out.println("Hello!world!! " + str);
                                out.flush();
                                if (str == null || str.equals("end"))
                                    break;
                                System.out.println(str);
                            }
                            socket.close();
                        }catch(IOException e){
                            e.printStackTrace();
                        }
                    }
                }).start();
            }catch(IOException e){
                e.printStackTrace();
            }
        }
    }
    
}

• SocketClient類，客戶端實現：

package client;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
public class SocketClient {
  static Socket client;
     
    public  SocketClient(String site, int port){
        try{
            client = new Socket(site,port);
            System.out.println("Client is created! site:"+site+" port:"+port);
        }catch (UnknownHostException e){
            e.printStackTrace();
        }catch (IOException e){
            e.printStackTrace();
        }
    }
    
    public String sendMsg(String msg){
        try{
            BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
            PrintWriter out = new PrintWriter(client.getOutputStream());
            out.println(msg);
            out.flush();
            return in.readLine();
        }catch(IOException e){
            e.printStackTrace();
        }
        return "";
    }
    public void closeSocket(){
        try{
            client.close();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
    public static void main(String[] args) throws Exception{
        
    }
}

接下來就是來測試Socket通訊了！

 先運行TestServer類，打開服務端，在12345端口處監聽！

package server;
public class TestServer {
 /**
  * @param args
  */
 public static void main(String[] argvs){
           SocketServer server = new SocketServer(1234);
           server.beginListen();
      }
}

 再運行TestClient類： 

package client;
public class TestClient {
 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
        SocketClient client = new SocketClient("127.0.0.1",1234);
        System.out.println(client.sendMsg("nimei1"));
        client.closeSocket();
        
        SocketClient client1 = new SocketClient("127.0.0.1",1234);
        System.out.println(client1.sendMsg("nimei1111"));
        client1.closeSocket();
        
        SocketClient client11 = new SocketClient("127.0.0.1",1234);
        System.out.println(client11.sendMsg("nimei11111111"));
        client11.closeSocket();
        
        SocketClient client111 = new SocketClient("127.0.0.1",1234);
        System.out.println(client111.sendMsg("nimei11111111111111111"));
        client111.closeSocket();
        
 }
}

輸出結果以下：

服務端：

nimei1
nimei1111
nimei11111111
nimei11111111111111111

 

客戶端：

Client is created! site:127.0.0.1 port:1234
Hello!world!! nimei1
Client is created! site:127.0.0.1 port:1234
Hello!world!! nimei1111
Client is created! site:127.0.0.1 port:1234
Hello!world!! nimei11111111
Client is created! site:127.0.0.1 port:1234
Hello!world!! nimei11111111111111111