从零学Netty（一）BIO通信

雨点打透心脏的1/2处 2022-12-13 04:35 277阅读 0赞

# BIO概念 #

同步阻塞I/O模式，全称BlockingIO，数据的读取写入必须阻塞在一个线程内等待其完成

它是基于流模型实现的，交互的方式是同步、阻塞方式，也就是说在读入输入流或者输出流时，在读写动作完成之前，线程会一直阻塞在那里，它们之间的调用时可靠的线性顺序。

它的优点就是代码比较简单、直观；缺点就是 IO 的效率和扩展性很低，容易成为应用性能瓶颈。

# 原理图 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70][]

图片来源：[https://mp.weixin.qq.com/s/CRd3-vRD7xwoexqv7xyHRw][https_mp.weixin.qq.com_s_CRd3-vRD7xwoexqv7xyHRw]

# 实例demo #

服务端代码

/**
     * bio服务端
     *
     * @author LionLi
     */
    public class BioServer {
    
        public static void main(String[] args) {
            try {
                // 创建服务端socket
                ServerSocket server = new ServerSocket(8088);
                System.out.println("服务端启动成功!!!");
                // 堵塞
                Socket socket = server.accept();
                // 创建消息处理器
                new ServerHandler(socket);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
    }

服务端消息处理器

/**
     * bio服务端消息处理
     *
     * @author LionLi
     */
    public class ServerHandler {
    
        public ServerHandler(Socket socket) {
            try (InputStreamReader isr = new InputStreamReader(socket.getInputStream());
                 BufferedReader br = new BufferedReader(isr);
                 PrintWriter pw = new PrintWriter(socket.getOutputStream(), true)) {
                String body;
                Scanner scanner = new Scanner(System.in);
                while (true) {
                    // 读取客户端消息
                    body = br.readLine();
                    if (body == null) {
                        break;
                    }
                    System.out.println("客户端: " + body);
                    String s = scanner.nextLine();
                    System.out.println("服务端: " + s);
                    // 发送到客户端
                    pw.println(s);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
    }

客户端代码

/**
     * bio客户端
     *
     * @author LionLi
     */
    public class BioClient {
    
        public static void main(String[] args) {
    
            try (Socket socket = new Socket("localhost", 8088);
                 InputStreamReader isr = new InputStreamReader(socket.getInputStream());
                 BufferedReader br = new BufferedReader(isr);
                 PrintStream ps = new PrintStream(socket.getOutputStream())) {
    
                System.out.println("请输入内容: ");
                Scanner scanner = new Scanner(System.in);
                String str = scanner.nextLine();
                System.out.println("客户端: " + str);
                // 发送到服务端
                ps.println(str);
                String response;
                while (true) {
                    // 读取服务端消息
                    response = br.readLine();
                    if (response == null || response.length() == 0) {
                        break;
                    }
                    System.out.println("服务端: " + response);
                    String client = scanner.nextLine();
                    System.out.println("客户端: " + client);
                    ps.println(client);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
    }

非常简单的一个通讯

# 测试 #

启动服务端

![20201010110956707.png][]

启动客户端

![20201010111015780.png][]

客户端发送消息给服务端

![20201010111045962.png][]

![20201010111059742.png][]

服务端回复消息

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70 1][]

![20201010111143512.png][]

项目已上传到gitee

地址: [netty-demo][]

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70]: /images/20221123/b0fcfa4c0997469ca3d25014dccb04dc.png
[https_mp.weixin.qq.com_s_CRd3-vRD7xwoexqv7xyHRw]: https://mp.weixin.qq.com/s/CRd3-vRD7xwoexqv7xyHRw
[20201010110956707.png]: /images/20221123/ec98f92bb1d345fd8047e55b86ea9143.png
[20201010111015780.png]: /images/20221123/883687ceedab4401bf733997627293d1.png
[20201010111045962.png]: /images/20221123/7df0ff12f7534c72ae3d016daebb1359.png
[20201010111059742.png]: /images/20221123/1e8d7f9efa474e378e44fd19aa277ab3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MDQ2MTI4MQ_size_16_color_FFFFFF_t_70 1]: /images/20221123/a832ffb228d8420fa1173c6b997ae3db.png
[20201010111143512.png]: /images/20221123/edfc43ac335d4d8b9da3025520fee0df.png
[netty-demo]: https://gitee.com/JavaLionLi/LionLi-Labs/tree/master/netty-demo