tcp/ip 服务器 【Java EE 初阶】网络编程套接字TCP的实现

目录

1.实现一个TCP的回显服务

1.Sever Socket API

1.SeverSocket 构造方法

2.Sever Socket方法

 2.Socket API

1.Socket的构造方法

2.Socket 方法

那么怎么实现让服务器可以处理多个客户端呢？

服务端代码：

客户端代码：

1.实现一个TCP的回显服务

1.Sever Socket API

Sever Socket 是创建TCP服务端Socket的API

1.SeverSocket 构造方法

2.Sever Socket方法

 2.Socket API

1.Socket的构造方法

2.Socket 方法

但是此服务器只能连接一个客户端，如果需要连接另一个客户端，只能让当前客户端断开连接，再连接另一个客户端

那么怎么实现让服务器可以处理多个客户端呢？

1.可以为每一个客户创建一个新的线程，让请求的处理在单独的子线程中去执行

但是这样如果有一万个客户端需要连接那就要创建一万个线程，会消耗非常大的系统资源，这时我们就可以通过线程池的方式进行优化，只给真正有需要的客户端建立连接

服务端代码：

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.net.ServerSocket;

import java.net.Socket;

import java.text.MessageFormat;

import java.util.Scanner;

import java.util.concurrent.LinkedBlockingDeque;

import java.util.concurrent.ThreadPoolExecutor;

import java.util.concurrent.TimeUnit;

public class TCPEchoSever {

private ServerSocket server;

public TCPEchoSever(int port) throws IOException {

if (port < 1025 || port > 65535) {

throw new RuntimeException("端口号要在 1025 ~ 65535之间.");

}

//实例化SeverSocket对象

this.server = new ServerSocket(port);

}

public void start() throws IOException {

System.out.println("服务器已启动~~");

ThreadPoolExecutor poolExecutor = new ThreadPoolExecutor(3,10,1, TimeUnit.SECONDS,new LinkedBlockingDeque<>(10));

// 循环接收客户端的连接

while (true) {

//接收客户端的数据

Socket clientSocket = server.accept();

// 提交任务到线程池中

poolExecutor.submit(() -> {

try {

processConnections(clientSocket);

} catch (IOException e) {

e.printStackTrace();

}

});

}

}

//处理数据

private void processConnections(Socket clientSocket) throws IOException {

// 打印日志

String clientInfo = MessageFormat.format("[{0}:{1}] 客户端已上线", clientSocket.getInetAddress(),

clientSocket.getPort());

System.out.println(clientInfo);

try (InputStream inputStream = clientSocket.getInputStream();

OutputStream outputStream = clientSocket.getOutputStream()){

while (true) {

Scanner requestScanner = new Scanner(inputStream);

if (!requestScanner.hasNextLine()) {

// 日志

clientInfo = MessageFormat.format("[{0}:{1}] 客户端已下线.", clientSocket.getInetAddress(),

clientSocket.getPort());

System.out.println(clientInfo);

break;

}

String request = requestScanner.nextLine();

String response = process(request);

PrintWriter printWriter = new PrintWriter(outputStream);

printWriter.println(response);

printWriter.flush();

// 打印日志

clientInfo = MessageFormat.format("[{0}:{1}], request: {2}, response: {3}",

clientSocket.getInetAddress(), clientSocket.getPort(), request, response);

System.out.println(clientInfo);

}

} catch (IOException e) {

throw new RuntimeException(e);

} finally {

clientSocket.close();

}

}

private String process(String request) {

System.out.println("收到新消息：" + request);

Scanner scanner = new Scanner(System.in);

String response = scanner.nextLine();

return response;

}

public static void main(String[] args) throws IOException {

TCPEchoSever server = new TCPEchoSever(6666);

server.start();

}

}

 客户端代码：

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.net.Socket;

import java.util.Scanner;

public class TCPEchoClient {

private Socket clientSocket;

public TCPEchoClient (String serverIp, int serverPort) throws IOException, IOException {

this.clientSocket = new Socket(serverIp, serverPort);

}

public void start() throws IOException {

System.out.println("客户端已启动~~");

// 获取Socket中的输入输出流

try (InputStream inputStream = clientSocket.getInputStream();

OutputStream outputStream = clientSocket.getOutputStream()) {

// 循环处理用户的输入

while (true) {

System.out.println("->");

// 接收用户的输入内容

Scanner requestScanner = new Scanner(System.in);

String request = requestScanner.nextLine();

// 发送用户的请求

PrintWriter printWriter = new PrintWriter(outputStream);

printWriter.println(request);

// 强制刷新缓冲区

printWriter.flush();

// 接收服务器的响应

Scanner responseScanner = new Scanner(inputStream);

// 获取响应数据

String response = responseScanner.nextLine();

// 打印响应内容

System.out.println("接收到服务器的响应：" + response);

}

} catch (IOException e) {

e.printStackTrace();

} finally {

clientSocket.close();

}

}

public static void main(String[] args) throws IOException {

TCPEchoClient client = new TCPEchoClient("127.0.0.1", 6666);

client.start();

}

}

推荐阅读