NIODiscardServer

Posted 2022-03-28 玩葫芦的卷心菜

文章目录

• • 1、步骤
  • 2、Server
  • 3、Client

Discard服务器仅读取客户端输入的数据，立马关闭信道后丢弃数据

1、步骤

1. 生成服务器信道
2. 信道绑定ip、port
3. 设置为非阻塞并注册到选择器为接收模式
4. select轮询已注册的就绪事件
5. 对就绪事件进行相应处理
6. 接收就绪，获取连接信道并设置非注册注册到选择器为读模式
7. 读就绪，获取连接信道读后直接丢弃数据

注意：注册到选择器上的信道必须为非阻塞模式，文件信道不支持非阻塞就必定不能注册选择器

2、Server

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

public class DiscardServer implements Runnable

    public static void main(String[] args) 
        new Thread(new DiscardServer(8090)).start();
    

    private int port;

    DiscardServer(int port)
        this.port = port;
    

    @Override
    public void run() 
        ServerSocketChannel server = null;
        Selector selector = null;
        try 
            server = ServerSocketChannel.open();
            server.bind(new InetSocketAddress(port));
            server.configureBlocking(false);//非阻塞
            selector = Selector.open();
            server.register(selector, SelectionKey.OP_ACCEPT);//注册到选择器

            while(selector.select() > 0)
                Iterator<SelectionKey> selectionKeys = selector.selectedKeys().iterator();
                while(selectionKeys.hasNext())
                    SelectionKey selectionKey = selectionKeys.next();

                    if(selectionKey.isAcceptable())
                        //接受到连接就设置非阻塞注册到选择器
                        System.out.println("收到连接");
                        SocketChannel client = server.accept();
                        client.configureBlocking(false);//非阻塞
                        client.register(selector, SelectionKey.OP_READ);
                    else if(selectionKey.isReadable())
                        //读任务就丢弃
                        System.out.println("收到读");
                        SocketChannel clientChannel =(SocketChannel) selectionKey.channel();
                        ByteBuffer buffer = ByteBuffer.allocate(1024);
                        int len = -1;
                        while( (len = clientChannel.read(buffer)) != -1)
                            buffer.flip();
                            System.out.println(new String(buffer.array(), 0, len));
                            buffer.clear();
                        
                        clientChannel.close();
                    
                    selectionKeys.remove();
                
            
         catch (IOException e) 
            e.printStackTrace();
         finally 
            if(selector != null)
                try 
                    selector.close();
                 catch (IOException e) 
                    e.printStackTrace();
                
            
            if(server != null)
                try 
                    server.close();
                 catch (IOException e) 
                    e.printStackTrace();
                
            
        
    

3、Client

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

public class C1Demo 
    public static void main(String[] args) 
        SocketChannel socketChannel = null;
        try 
            socketChannel = SocketChannel.open();
            socketChannel.configureBlocking(false);
            socketChannel.connect(new InetSocketAddress("127.0.0.1",8090));
            while(!socketChannel.finishConnect())

            
            System.out.println("获取到连接");
            ByteBuffer byteBuffer = ByteBuffer.allocate(1024);

            Scanner sc = new Scanner(System.in);
            String msg = sc.nextLine();

            byteBuffer.put(msg.getBytes());
            byteBuffer.flip();
            socketChannel.write(byteBuffer);
            byteBuffer.clear();
            socketChannel.shutdownOutput();

         catch (IOException e) 
            e.printStackTrace();
         finally 
            try 
                if(socketChannel != null)
                    socketChannel.close();
             catch (IOException e) 
                e.printStackTrace();