一个 Java 的 Socket 服务器和客户端通信的例子

Posted 2020-10-13 NeverSayDie

http://blog.csdn.net/defonds/article/details/7971259

多个客户端对应一个服务端的通信的一个小例子。

 服务端和客户端代码：

public class Server {
    /**
     * 监听的端口
     */
    public static final int PORT = 12345;

    public static void main(String[] args) {
        System.out.println("服务器启动》》》》》》");
        Server server = new Server();
        server.init();
    }

    public void init(){
        try {
            ServerSocket serverSocket = new ServerSocket(PORT);
            while (true){
                //一旦有堵塞，表示服务器与客户端获得了连接
                Socket client = serverSocket.accept();
                new HandlerThread(client);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private class HandlerThread implements Runnable{
        private Socket socket;

        public HandlerThread(Socket socket) {
            this.socket = socket;
            new Thread(this).start();
        }
        @Override
        public void run() {
            try {
                //读取客户端数据
                DataInputStream input = new DataInputStream(socket.getInputStream());
                //这里要注意和客户端输出流的写方法对应,否则会抛 EOFException
                String clientInputStr = input.readUTF();
                //处理客户端发送的数据
                System.out.println("客户端发过来的内容："+clientInputStr);
                //想客户端发送消息
                DataOutputStream out = new DataOutputStream(socket.getOutputStream());
                System.out.println("请输入：\t");
                String outStr = new BufferedReader(new InputStreamReader(System.in)).readLine();
                out.writeUTF(outStr);
                out.close();
                input.close();

            } catch (IOException e) {
                System.out.println("服务器异常："+e.getMessage());
            }finally {
                if (socket != null) {
                    try {
                        socket.close();
                    } catch (Exception e) {
                        socket = null;
                        System.out.println("服务端 finally 异常:" + e.getMessage());
                    }
                }
            }
        }
    }

}

public class Client {
    public static final int PORT = 12345;
    public static final String IP_ADDR = "localhost";

    public static void main(String[] args) {
        System.out.println("客户端启用》》》》》》");
        System.out.println("当接收到服务器端字符为 \"OK\" 的时候, 客户端将终止\n");
        while (true){
            Socket socket = null;
            try {
                //创建一个流套接字并将其连接到指定主机上的指定端口号
                socket = new Socket(IP_ADDR,PORT);
                socket.setSoTimeout(5000);
                //读取服务器端数据
                DataInputStream input = new DataInputStream(socket.getInputStream());
                //向服务器端发送数据
                DataOutputStream out = new DataOutputStream(socket.getOutputStream());
                System.out.print("请输入: \t");
                String str = new BufferedReader(new InputStreamReader(System.in)).readLine();
                out.writeUTF(str);

                String ret = input.readUTF();
                System.out.println("服务器端返回过来的是: " + ret);

                if (ret.endsWith("OK")) {
                    System.out.println("客户端将关闭连接");
                    Thread.sleep(500);
                    break;
                }
                out.close();
                input.close();


            } catch (IOException  | InterruptedException e) {
                e.printStackTrace();
            }finally {
                if (socket != null) {
                    try {
                        socket.close();
                    } catch (IOException e) {
                        socket = null;
                        System.out.println("客户端 finally 异常:" + e.getMessage());
                    }
                }
            }
        }
    }
}