NIO 交互简单示例

客户端代码：

package test;

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

public class Client {
    public static void main(String[] args) {
        try(SocketChannel socketChannel = SocketChannel.open()){
            socketChannel.connect(new InetSocketAddress("127.0.0.1",8800));
            ByteBuffer writeBuff = ByteBuffer.allocate(1024);
            ByteBuffer readBuff = ByteBuffer.allocate(1024);
            writeBuff.put("Hello server".getBytes());
            writeBuff.flip();

            while (true){
                writeBuff.rewind();
                socketChannel.write(writeBuff);
                readBuff.clear();
                socketChannel.read(readBuff);
                System.out.println("Client receive:" + new String(readBuff.array()));
            }
        }catch (Exception ex){
            ex.printStackTrace();
        }
    }
}

服务器端代码

package test;

import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

public class Server {

    public static void main(String[] args) {
        try (Selector selector = Selector.open()) {
            try (ServerSocketChannel ssc = ServerSocketChannel.open()) {
                ssc.socket().bind(new InetSocketAddress("127.0.0.1", 8800));
                ssc.configureBlocking(false);
                ssc.register(selector, SelectionKey.OP_ACCEPT);
                ByteBuffer readBuff = ByteBuffer.allocate(1024);
                ByteBuffer writeBuff = ByteBuffer.allocate(1024);
                writeBuff.put("Hello client".getBytes());
                writeBuff.flip();

                while (true) {
                    int readyNum = selector.select();
                    if (readyNum == 0) {
                        continue;
                    }
                    Set<SelectionKey> keys = selector.selectedKeys();
                    Iterator<SelectionKey> iterator = keys.iterator();
                    while (iterator.hasNext()) {
                        SelectionKey key = iterator.next();
                        if (key.isAcceptable()) {
                            SocketChannel socketChannel = ssc.accept();
                            socketChannel.configureBlocking(false);
                            socketChannel.register(selector, SelectionKey.OP_READ);
                        } else if (key.isReadable()) {
                            try(SocketChannel socketChannel = (SocketChannel) key.channel()){
                                readBuff.clear();
                                socketChannel.read(readBuff);
                                readBuff.flip();
                                System.out.println("Server receive:" + new String(readBuff.array()));
                                key.interestOps(SelectionKey.OP_WRITE);
                            }
                        } else if (key.isWritable()) {
                            try(SocketChannel socketChannel = (SocketChannel) key.channel()){
                                writeBuff.rewind();
                                socketChannel.write(writeBuff);
                                key.interestOps(SelectionKey.OP_READ);
                            }
                        }
                        iterator.remove();
                    }
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}