Java基础之Java NIO

NIO Server

package com.nio.server;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.nio.charset.StandardCharsets;
import java.util.Iterator;


public class NIOServer {
    
    private Selector selector;

    
    ServerSocketChannel serverSocketChannel;

    public void initServer(int port) throws IOException {
        //打开一个通道
        serverSocketChannel = ServerSocketChannel.open();

        //通道设置非阻塞
        serverSocketChannel.configureBlocking(false);

        //绑定端口号
        serverSocketChannel.socket().bind(new InetSocketAddress("localhost", port));

        //注册
        this.selector = Selector.open();
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
    }

    public void listen() throws IOException {
        System.out.println("服务启动成功...");

        while (true) {
            selector.select();
            Iterator ite = selector.selectedKeys().iterator();
            while (ite.hasNext()) {
                SelectionKey key = ite.next();
                if (key.isAcceptable()) {
                    SocketChannel channel = serverSocketChannel.accept();
                    channel.configureBlocking(false);
                    channel.register(selector, SelectionKey.OP_READ);
                }
                if (key.isReadable()) {
                    recvAndReply(key);
                }
                ite.remove();
            }
        }
    }

    public void recvAndReply(SelectionKey key) throws IOException {
        SocketChannel channel = (SocketChannel) key.channel();
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        int i = channel.read(buffer);
        if (i != -1) {
            String msg = new String(buffer.array()).trim();
            System.out.println("NIO服务端收到消息:" + msg);
            channel.write(ByteBuffer.wrap("我是服务端!".getBytes(StandardCharsets.UTF_8)));
            System.out.println("NIO服务端返回消息:" + "我是服务端!");
        } else {
            channel.close();
        }
    }

    public static void main(String[] args) throws IOException {
        NIOServer server = new NIOServer();
        server.initServer(8080);
        server.listen();
    }
}

NIO Client

package com.nio.client;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;


public class NIOClient {
    
    SocketChannel channel;

    public void initClient(String host, int port) throws IOException {
        //构造socket连接
        InetSocketAddress servAddr = new InetSocketAddress(host, port);

        //打开连接
        this.channel = SocketChannel.open(servAddr);
    }

    public void sendAndRecv(String words) throws IOException {
        byte[] msg = words.getBytes();
        ByteBuffer buffer = ByteBuffer.wrap(msg);
        System.out.println("客户端发送消息: " + words);
        channel.write(buffer);
        buffer.clear();

        channel.read(buffer);
        System.out.println("客户端收到消息: " + new String(buffer.array()).trim());
        channel.close();
    }

    public static void main(String[] args) throws IOException {
        NIOClient client = new NIOClient();
        client.initClient("localhost", 8080);
        client.sendAndRecv("我是客户端!");
    }
}