一文理清什么是BIO以及如何使用

 public static void main(String[] args) {
        System.out.println("===服务端启动===");
        ServerSocket serverSocket=null;
        try {
            serverSocket=new ServerSocket(5000);
            Socket socket=serverSocket.accept();
            InputStream is = socket.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            String msg;
            if ((msg = br.readLine()) != null) {
                System.out.println("服务端接收客户端信息为：" + msg);
            }
        }catch (Exception exception){
            System.out.println(exception.getMessage());
        }
  }

public static void main(String[] args) {
        Socket socket = null;
        try {
            socket = new Socket("127.0.0.1",5000);
            OutputStream os = socket.getOutputStream();
            PrintStream ps = new PrintStream(os);
            ps.println("Hi BIO! 与服务端通信成功");
            ps.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

public static void main(String[] args) {
    System.out.println("===服务端启动===");
    try {
         ServerSocket ss = new ServerSocket(9988);
         Socket socket = ss.accept();
         InputStream is = socket.getInputStream();
         BufferedReader br = new BufferedReader(new InputStreamReader(is));
         String message;
         while ((message = br.readLine()) != null){
             System.out.println("服务端接收客户端信息为：" + message);
         }
     } catch (IOException e) {
            e.printStackTrace();
     }
}

public static void main(String[] args) {
    try {
        Socket socket = new Socket("localhost",9988);
        OutputStream os = socket.getOutputStream();
        PrintStream ps = new PrintStream(os);
        Scanner scanner = new Scanner(System.in);
        while (true){
            System.out.println("请输入：");
            String input = scanner.nextLine();
            ps.println(input);
            ps.flush();
        }
     } catch (IOException e) {
            e.printStackTrace();
     }
}

  public void listen() throws IOException {
        ServerSocket serverSocket = null;
        try {
            log.info("服务启动监听");
            serverSocket = new ServerSocket(9988);
            //循环接收到客户端的连接
            while (true) {
                Socket socket = serverSocket.accept();
                //得到连接后，开启一个线程处理连接
                handleSocket(socket);
            }
        }finally {
            if(serverSocket != null){
                serverSocket.close();
            }
        }
 }
private void handleSocket(Socket socket) {
        HandleSocket socketHandle = new HandleSocket(socket);
        new Thread(socketHandle).start();
}

 public void run() {
        BufferedInputStream bufferedInputStream = null;
        BufferedOutputStream bufferedOutputStream  = null;
        try {
            bufferedInputStream = new BufferedInputStream(socket.getInputStream());
            byte[] bytes = new byte[1024];
            int len ;
            if ((len = bufferedInputStream.read(bytes)) > -1) {
                String result = new String(bytes,0,len);
                System.out.println("本次接收到的结果："+result);
            }
            System.out.println("回复信息给客户端：");
            bufferedOutputStream = new BufferedOutputStream(socket.getOutputStream());
            String outString = Thread.currentThread().getName()+"接收到了";
            bufferedOutputStream.write(outString.getBytes());
            bufferedOutputStream.flush();
            System.out.println("回复完成：");
        } catch (IOException e) {
            System.out.println("异常："e.getLocalizedMessage());
        } finally {
            System.out.println("关闭数据流：");
            try {
                if (bufferedInputStream != null) {
                    bufferedInputStream.close();
                }
                if (bufferedOutputStream != null) {
                    bufferedOutputStream.close();
                }
            }catch (IOException e){
                System.out.println("请输入："e.getLocalizedMessage());
            }
        }
    }

  public void start() throws IOException {
        Socket socket = new Socket("127.0.0.1", 8081);
        String msg = "Hi,This is the BioClient";
        //1.拿到输出流
        //2.对输出流进行处理
       System.out.println("请输入："+msg);
        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(socket.getOutputStream());
        byte[] bytes = msg.getBytes();
        //3.输出msg
        bufferedOutputStream.write(bytes);
        bufferedOutputStream.flush();
        System.out.println("发送完毕.");
        System.out.println("开始接收到消息.");
        //4.对输入流进行处理
        BufferedInputStream bufferedInputStream = new BufferedInputStream(socket.getInputStream());
        byte[] inBytes = new byte[1024];
        int len;
        //5.读取输入流
        if ((len = bufferedInputStream.read(inBytes)) != -1) {
            String result = new String(inBytes, 0, len);
            System.out.println("接收到的消息="+result);
        }
        //6.关闭输入输出流
        bufferedOutputStream.close();
        bufferedInputStream.close();
        socket.close();
    }