Java Socket之单线程通信



Java Socket之单线程通信

博客分类：
• java
• java基础

java java基础 socket 网络编程 

1、 服务器端处理流程

    接触一种技术，首先都要熟悉它的生命周期，这样才能从大局上看每个流程的细节。才有居高临下，势如劈竹的架势。加深我们对这种技术的理解。现在来看看socket服务器的生命周期。   

    socket程序，一般情况下，都是服务器与客户端成双成对出现。

    服务器端socket的生命周期为：监听服务器端口，接受客户端连接，获取客户端输入、输出流，处理业务逻辑、发送响应信息，关闭客户端连接，关闭服务区监听。详情如下所示：

 

2、 客户端处理流程

    socket程序的客户端的处理流程与服务器的相似，生命周期为：创建客户端socket，获取服务器输入、输出流，处理业务逻辑、发送相应信息、关闭客户端连接。详情如下所示：

 

3、 实例代码

    首先是写一个Server类，这个类用来监听9999端口，并从这个端口接收消息然后输出，当收到“bye”时退出。

public class MyServer {

    public static void main(String[] args) throws IOException {
        int port = 9999;

        // 监听服务器端口
        ServerSocket server = new ServerSocket(port);
        System.out.println("listening on " + port);

        while (true) {
            // 接受一个客户端连接
            Socket socket = server.accept();
            System.out.println("---------------------------");
            System.out.println("the client " + socket.getInetAddress().getHostAddress() + " has connected!");

            // 获取客户端的输入流
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            // 获取客户端的输出流
            PrintWriter out = new PrintWriter(socket.getOutputStream());

            String msg = in.readLine();
            System.out.println("Server received " + msg);

            if (msg.equals("bye")) {
                System.out.println("Server stoped!");
                break;
            } else {
                // 想客户端发送信息
                System.out.println("Server send " + msg);
                out.print("Server received " + msg);
                out.flush();
            }
            socket.close();
        }
        server.close();
    }

}

public class MyServer {

	public static void main(String[] args) throws IOException {
		int port = 9999;
		
		// 监听服务器端口
		ServerSocket server = new ServerSocket(port);
		System.out.println("listening on " + port);
		
		while (true) {
			// 接受一个客户端连接
			Socket socket = server.accept();
			System.out.println("---------------------------");
			System.out.println("the client " + socket.getInetAddress().getHostAddress() + " has connected!");
			
			// 获取客户端的输入流
			BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));  
			// 获取客户端的输出流
	        PrintWriter out = new PrintWriter(socket.getOutputStream());
	        
			String msg = in.readLine();
			System.out.println("Server received " + msg);
			
			if (msg.equals("bye")) {
				System.out.println("Server stoped!");
				break;
			} else {
				// 想客户端发送信息
				System.out.println("Server send " + msg);
				out.print("Server received " + msg);
				out.flush();
			}
			socket.close();
		}
		server.close();
	}

}

 

   然后是一个Client类，这个类连接上面启动的Server类，然后接收任何用户输入，当遇到回车时发送字符串到Server上，当输入“bye”是退出。

public class MyClient {

    public static void main(String[] args) throws UnknownHostException, IOException {
        Scanner reader = new Scanner(System.in);

        while (true) {
            // 创建客户端socket
            Socket client = new Socket("localhost", 9999);
            System.out.println("---------------------------");

            // 获取客户端的输入流（获取服务器端的输出流）
            BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
            //
            PrintWriter out = new PrintWriter(client.getOutputStream());

            System.out.println("Input Something ");
            String msg = reader.nextLine();
            System.out.println("Client sended " +  msg);
            out.println(msg);
            out.flush();
            if (msg.equals("bye")) {
                System.out.println("Client stop!");
                break;
            }
            System.out.println("Client received " + in.readLine());
            client.close();
        }
    }

}

public class MyClient {

	public static void main(String[] args) throws UnknownHostException, IOException {
    	Scanner reader = new Scanner(System.in);
		
        while (true) {
        	// 创建客户端socket
        	Socket client = new Socket("localhost", 9999);
        	System.out.println("---------------------------");
        	
        	// 获取客户端的输入流（获取服务器端的输出流）
        	BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream())); 
        	// 
            PrintWriter out = new PrintWriter(client.getOutputStream()); 
            
            System.out.println("Input Something ");
        	String msg = reader.nextLine(); 
        	System.out.println("Client sended " +  msg);
            out.println(msg);  
            out.flush();  
            if (msg.equals("bye")) {  
            	System.out.println("Client stop!");
                break;  
            }  
            System.out.println("Client received " + in.readLine());
            client.close();
        }
	}

}

 

4、 结果

   首先运行MyServer类，然后MyClient类，然后在MyClient的控制台输入任意字符。

   服务器端

listening on 9999
---------------------------
the client 127.0.0.1 has connected!
Server received i am here
Server send i am here
---------------------------
the client 127.0.0.1 has connected!
Server received bye
Server stoped!

listening on 9999
---------------------------
the client 127.0.0.1 has connected!
Server received i am here
Server send i am here
---------------------------
the client 127.0.0.1 has connected!
Server received bye
Server stoped!

 

   客户端

---------------------------
Input Something
i am here
Client sended i am here
Client received Server received i am here
---------------------------
Input Something
bye
Client sended bye
Client stop!

---------------------------
Input Something 
i am here
Client sended i am here
Client received Server received i am here
---------------------------
Input Something 
bye
Client sended bye
Client stop!