java socket实现客户端服务端通信

作者ChihMinh，原作链接https://chihminh.github.io/2016/07/28/java-socket-commu/，转载请注明出处

在java sockets源码一瞥中从代码的角度分析了Socket和ServerSocket，现在来实战一下

socket 实现客户端与服务端通信

客户端程序：

public class SocketClient {
    public static void main(String[] args) {
        try {

            // 客户端与指定主机名和端口的服务端绑定
            Socket socket = new Socket("127.0.0.1", 3600);
            System.out.println("连接成功");

            // 由socket对象得到输出流
            PrintWriter printer = new PrintWriter(socket.getOutputStream());

            // 由socket对象得到输入流，并将输入字节流转换为字符流
            BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            // 读取输入流的一行数据

            String res = "";
            String in = "";
            while (!res.contains("bye") && !in.contains("bye")) {
                // 读取系统输入，将其从字节流准换位字符流
                BufferedReader sysin = new BufferedReader(new InputStreamReader(System.in));
                in = sysin.readLine();
                printer.println(in);
                // 刷新输出流，使服务端马上收到字符串
                printer.flush();

                res = reader.readLine();
                System.out.println("Server says: " + res);
            }

            System.out.println("连接关闭");
            printer.close();
            reader.close();
            socket.close();


        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

服务端程序：

public class SocketServer {
    public static void main(String[] args) {
       try {
           ServerSocket server = new ServerSocket(3600);

           while (true) {
               Socket client = server.accept();
               System.out.println("连接成功");

               PrintWriter writer = new PrintWriter(client.getOutputStream());
               BufferedReader reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
               String res = "";
               String in = "";
               while (!res.contains("bye") && !in.contains("bye")) {
                   res = reader.readLine();
                   System.out.println("Client says: " + res);

                   BufferedReader sysIn = new BufferedReader(new InputStreamReader(System.in));
                   in = sysIn.readLine();
                   writer.println(in);
                   writer.flush();
               }

               System.out.println("连接关闭");
               reader.close();
               writer.close();
               client.close();
           }


       } catch (IOException e) {
           e.printStackTrace();
       }
    }
}

这样同一时刻只能有一个客户端和服务端通信，下面用并发实现多个客户端同时与服务端通信。

多个客户端与服务端通信

客户端代码：

public class SocketClient {
    public static void main(String[] args) {
        try {
            //
            Socket socket = new Socket("127.0.0.1", 3600);
            System.out.println("与服务端连接成功！");
            // 得到输出流
            PrintWriter writer = new PrintWriter(socket.getOutputStream());
            // 得到输入流
            BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));


            String output = "";
            String input = "";
            // 通信
            while (!output.contains("bye") && !input.contains("bye")) {
                System.out.print("Me: ");
                // 从控制台输入
                BufferedReader sysIn = new BufferedReader(new InputStreamReader(System.in));
                output = sysIn.readLine();
                writer.println(output);
                writer.flush();

                input = reader.readLine();
                System.out.println("Server: " + input);
            }

            // 关闭socket对象
            writer.close();
            reader.close();
            socket.close();
            System.out.println("与服务端连接断开！");
        } catch (IOException e) {}
    }
}

服务端代码：

public class ServerThread extends Thread {
    private Socket socket;

    public ServerThread(Socket socket) {
        this.socket = socket;

    }

    private void execute(Socket socket) throws IOException{
        BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter writer = new PrintWriter(socket.getOutputStream());

        String input = "";
        String output = "";
        while (!input.contains("bye") && !output.contains("bye")) {
            input = reader.readLine();
            System.out.println("Client: " + input);

            BufferedReader sysIn = new BufferedReader(new InputStreamReader(System.in));
            output = sysIn.readLine();
            writer.println(output);
            writer.flush();
        }

        reader.close();
        writer.close();
        socket.close();
        System.out.println("与客户端连接断开！");
    }

    @Override
    public void run() {
        try {
            execute(socket);
        } catch (IOException e) {}

    }
}

用线程池实现并发

public class ServerPool {

    public static void main(String[] args) {
        try {
            ServerSocket server = new ServerSocket(3600);
            ExecutorService pool = Executors.newFixedThreadPool(2);
            while(true) {
                Socket socket = server.accept();
                System.out.println("与客户端连接成功！");
                ServerThread serverThread = new ServerThread(socket);
                pool.submit(serverThread);
            }
        } catch (IOException e) {}
    }
}