Java套接字

前言：　

　　本文補充一下Java關於套接字方面的內容，因為其應用相對比較簡單，所以下面介紹兩個程序實例。

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1.Socket對接過程

(注：這是之前在網上見過一張圖片，大致過程還是比較清晰的）

分析：

• Socket對接之后的數據傳送類似於文件的讀寫；
• 流套接字采用TCP傳輸數據流，一旦數據發送失敗將重傳，所以具有安全無損的特點。

2.實例一【Server->Client(1:1)】

package socket;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;

public class Server {

    public Server(){
        try {
            //服務端開啟端口8000
            ServerSocket serverSocket = new ServerSocket(8000);
            System.out.println("server start at:"+new Date());
            //等待客戶端相應
            Socket socket  = serverSocket.accept();
            InetAddress address = socket.getInetAddress();
            System.out.println("connected with address:"+address.getHostAddress());
            DataInputStream input = new DataInputStream(socket.getInputStream());
            DataOutputStream output = new DataOutputStream(socket.getOutputStream());
            
            //while(true){
            int num = input.readInt();
            System.out.println(num);
            //}
        
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        new Server();
    }

}

package socket;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.Socket;

public class Client {
    public static void main(String[] args) throws Exception {
        
        System.out.println("--client--");
        
        //Socket(,)內參數分別設為服務端IP和端口
        Socket socket = new Socket("localhost", 8000);

        DataInputStream input = new DataInputStream(socket.getInputStream());
        DataOutputStream output = new DataOutputStream(socket.getOutputStream());
        
        int x = 222;
        output.writeInt(x);
        System.out.println("data convented:"+x);
    }
}

服務端輸出（執行之后顯示紅點，表示等待中...）：

 

server start at:Sat Aug 15 19:39:40 CST 2015
connected with address:127.0.0.1
222

客戶端輸出：

--client--
data convented:222

 

3.實例二【Server->Client(1:n)】

package socket;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;

public class SuperServer {
    private int countOfClient=0;
    public SuperServer() {
        try {
            ServerSocket serverSocket = new ServerSocket(8000);
            System.out.println("server start at:" + new Date());

            while (true) {
                Socket socket = serverSocket.accept();
                InetAddress address = socket.getInetAddress();
                System.out.println("connected with address:"
                        + address.getHostAddress());
                //為每一位Client創建一個單獨的線程
                new Thread(new ConnectTask(socket)).start();
                countOfClient++;
                System.out.println("this is the "+countOfClient + "(th) of client. ");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {
        new SuperServer();
    }

    class ConnectTask implements Runnable {
        private Socket socket = null;

        public ConnectTask(Socket socket) {
            this.socket = socket;
        }

        @Override
        public void run() {
            try {
                DataInputStream input = new DataInputStream(
                        socket.getInputStream());
                DataOutputStream output = new DataOutputStream(
                        socket.getOutputStream());
                
                int numFromClient = input.readInt();
                System.out.println("number from client:"+numFromClient);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

    }

}

　　以上代碼中，服務端創建多線程，給每一個對接的客戶端分一個獨立的線程；客戶端代碼不變，還是實例一的代碼。程序輸出跟實例一近似，只不過這是服務端一直運行着，可供多個客戶端連接。（因為獨立分配線程，程序運行時資源比較浪費，所以代碼僅供參考，有待優化！）