Java bio使用例子

下面是一个简单的Java BIO使用例子，实现了一个简单的通信服务端和客户端：

服务端代码：

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8888);
        System.out.println("Server started, listening on port 8888...");

        while (true) {
            Socket socket = serverSocket.accept();
            System.out.println("Client " + socket.getRemoteSocketAddress() + " connected");

            InputStream is = socket.getInputStream();
            OutputStream os = socket.getOutputStream();

            try {
                byte[] buffer = new byte[1024];
                int n;
                while ((n = is.read(buffer)) != -1) {
                    String s = new String(buffer, 0, n, "UTF-8");
                    System.out.println("Server received: " + s);
                    os.write(("Server received: " + s).getBytes("UTF-8"));
                }
            } catch (IOException e) {
                e.printStackTrace();
                System.out.println("Client " + socket.getRemoteSocketAddress() + " disconnected");
            } finally {
                socket.close();
            }
        }
    }
}

客户端代码：

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("localhost", 8888);
        System.out.println("Connected to server " + socket.getRemoteSocketAddress());

        InputStream is = socket.getInputStream();
        OutputStream os = socket.getOutputStream();

        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.print("Enter message (type 'exit' to quit): ");
            String line = scanner.nextLine();
            if ("exit".equals(line)) {
                break;
            }

            os.write(line.getBytes("UTF-8"));
            byte[] buffer = new byte[1024];
            int n = is.read(buffer);
            String s = new String(buffer, 0, n, "UTF-8");
            System.out.println("Client received: " + s);
        }

        socket.close();
    }
}

这个例子实现了一个简单的回显服务器，客户端可以向服务器发送消息，服务器接收到消息后回复给客户端。