Socket编程入门

Posted 2021-02-14 sinkinben

1. socket基本知识

网络上的两个程序通过一个双向的通信连接实现数据的交换，这个连接的一端称为一个socket。建立网络通信连接至少要一对端口号(socket)。socket本质是编程接口(API)，对TCP/IP的封装，TCP/IP也要提供可供程序员做网络开发所用的接口，这就是Socket编程接口；HTTP是轿车，提供了封装或者显示数据的具体形式；Socket是发动机，提供了网络通信的能力。

Java Socket的通信时序图如下。

Java Socket的数据通信模型如下。

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1. Java编程

2. 通信步骤

Server端	Client端
创建ServerSocker 绑定端口 等待端口的通信请求(此步会返回一个socket，这个socket作为server端的socket) 建立server端的socket的输入流(reader)和输出流(writer) reader可以获取client的通信数据，writer可以向client发送数据	创建一个socket 连接IP:port(要求server存在) 建立client的输入流(reader)和输出流(writer) reader可以获取server的通信数据，writer可以向server发送数据

1. 代码实例

• Server端

public class TestServer { ????public static final String datePattern = "yyyy-MM-dd HH:mm:ss SSS"; ????public static final SimpleDateFormat dateFormat = new SimpleDateFormat(datePattern); ???? ????public static void main(String[] args) throws IOException ????{ ????????//1.创建一个server socket服务 ????????ServerSocket serverSocket = new ServerSocket(); ????????//2.绑定端口 ????????InetSocketAddress address = new InetSocketAddress("localhost", 18824); ????????serverSocket.bind(address); ????????//3.等待和接收端口的通信请求，返回的是一个socket ????????PrintConsoleMsg("等待连接..."); ????????Socket socket = serverSocket.accept(); ????????PrintConsoleMsg("连接成功！"); ???????? ????????//服务端的输入与输出 ????????BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream())); ????????PrintWriter writer = new PrintWriter(socket.getOutputStream(), true); //true表示autoflush ???????? ????????//获取键盘输入 ????????BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); ???????? ????????while(true) ????????{ ????????????if(reader.ready()) ????????????{ ????????????????//捕获client的socket发来的消息 ????????????????PrintClientMsg(reader.readLine()); ????????????} ????????????if(keyboard.ready()) ????????????{ ????????????????//捕获当前server的键盘输入 ????????????????String content = keyboard.readLine(); ????????????????//打印在server的屏幕 ????????????????PrintConsoleMsg(content); ????????????????//发送到client ????????????????writer.println(content); ????????????} ????????} ???????? ????} ???? ????public static void PrintConsoleMsg(String msg) ????{ ????????System.out.println("Server: " + dateFormat.format(new Date()) + " " + msg); ????} ???? ????public static void PrintClientMsg(String msg) ????{ ????????System.out.println("Client: " + dateFormat.format(new Date()) + " " + msg); ????} }

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• Client端

public class TestClient { ????public static final String datePattern = "yyyy-MM-dd HH:mm:ss SSS"; ????public static final SimpleDateFormat dateFormat = new SimpleDateFormat(datePattern); ????public static void main(String[] args) throws UnknownHostException, IOException { ???????? ????????//1.创建一个socket ????????Socket socket = new Socket(); ????????//2.连接server的IP:端口 ????????InetSocketAddress address = new InetSocketAddress("localhost", 18824); ????????socket.connect(address); ????????//3.client socket的输入流和输出流 ????????BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream())); ????????PrintWriter writer = new PrintWriter(socket.getOutputStream(),true); ????????//当前client的键盘输入流 ????????BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); ???????? ????????while(true) ????????{ ????????????if(reader.ready()) ????????????{ ????????????????PrintServerMsg(reader.readLine()); ????????????} ????????????if(keyboard.ready()) ????????????{ ????????????????String content = keyboard.readLine(); ????????????????//打印在client的console ????????????????PrintConsoleMsg(content); ????????????????//发送给server ????????????????writer.println(content); ????????????} ????????} ????} ???? ????public static void PrintConsoleMsg(String msg) ????{ ????????System.out.println("Client: " + dateFormat.format(new Date()) + " " + msg); ????} ???? ????public static void PrintServerMsg(String msg) ????{ ????????System.out.println("Server: " + dateFormat.format(new Date()) + " " + msg); ????} }

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1. 运行结果

打开2个power shell分别作为server和client端。

1. 运行server端

1. 运行client进行连接

1. client输入信息，模拟通信

1. server输入回复信息

1. client输入回复信息

1. C++编程

待补充。

PS：word+cnblog发表博客first test。

参考文献

1. https://blog.csdn.net/luanlouis/article/details/19974999