Java Socket实现基于BIO的TCP通信

一、BIO

BIO，即同步并阻塞。服务端会在ServerSocket对象的accept方法发生阻塞，当有连接进入的时候，才能继续往下执行；读取数据，调用read方法时，也会发生阻塞。

二、服务端

public class BIOServer {

    public static void main(String[] args) {
        try {
            openServer(8888);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void openServer(int port) throws IOException {
//        创建ServerSocket
        ServerSocket serverSocket = new ServerSocket();
//        绑定端口
        serverSocket.bind(new InetSocketAddress(port));
        System.out.println("BIOServer启动...");
        while (true){
//            堵塞，等待客户端连接
            Socket socket = serverSocket.accept();
            System.out.println("连接成功...");
//            输入流
//            BufferedReader是缓冲输入流，InputStreamReader是转换输入流，InputStream是字节输入流
            BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            String str = null;
            while ((str = br.readLine()) != null){
                if("quit".equals(str)){
                    break;
                }
                System.out.println(str);
            }
//            关闭流
            br.close();
//            关闭socket
            socket.close();
            System.out.println("连接结束...");
        }

//        System.out.println("BIOServer关闭...");

    }

}

三、客户端

public class BIOClient {

    public static void main(String[] args) {
        try {
            connect("127.0.0.1", 8888);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void connect(String hostname, int port) throws IOException {
//        创建socket
        Socket socket = new Socket();
//        连接
        socket.connect(new InetSocketAddress(hostname, port));
//      输出流
//      BufferedWriter是缓冲输出流，OutputStreamWriter是转换输出流，OutputStream是字节输出流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));

//       标准输入流，从键盘输入
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        String str = null;
        while ((str = br.readLine()) != null){
//            如果从键盘输入quit，则退出循环
            if ("quit".equals(str)){
                break;
            }
            bw.write(str);
//            需要写换行，因为server端每次读取一行
            bw.newLine();
            bw.flush();
        }

//        关闭流
        br.close();
//        关闭socket
        socket.close();

    }

}