public class BIOServer {

public static void main(String[] args) {
    try {
        ServerSocket serverSocket = new ServerSocket();
        InetSocketAddress address = new InetSocketAddress("127.0.0.1", 9001);
        serverSocket.bind(address);
        while (true) {
            Socket socket = serverSocket.accept();
            new Thread(new Runnable() {
                @Override
                public void run() {
                    System.out.println(socket.getLocalAddress().getHostAddress() + "连接了");
                    InputStream inputStream = null;
                    try {
                        inputStream = socket.getInputStream();
                        InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
                        BufferedReader reader = new BufferedReader(inputStreamReader);
                        String str = null;
                        str = reader.readLine();
                        System.out.println(str);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

}

public class BIOClient {

public static void main(String[] args) {
    try {
        Socket socket = new Socket("127.0.0.1", 9001);
        OutputStream outputStream = socket.getOutputStream();
        OutputStreamWriter outputStreamWriter = new OutputStreamWriter(outputStream);
        BufferedWriter writer = new BufferedWriter(outputStreamWriter);
        String str = "你好";
        writer.write(str);
        //刷新输入流
        writer.flush();
        //关闭socket的输出流
        socket.shutdownOutput();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

}