2021-05-18通过SocketChannel 和 ServerSocketChannel 写一个阻塞的网络IO操作

通过SocketChannel 和 ServerSocketChannel 写一个阻塞的网络IO操作

package edu.xcdq;

/**
 * @qvthor liuwenzheng
 * @date 2021/5/18 20:50
 */

    import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Date;
import java.util.Iterator;
import java.util.Set;

    public class De {

        public static void main(String[] args) throws Exception {
            int port = 8000;

            // 通过open()方法找到Selector
            Selector selector = Selector.open();

            // 打开服务器的通道
            ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();

            // 服务器配置为非阻塞
            serverSocketChannel.configureBlocking(false);
            ServerSocket serverSocket = serverSocketChannel.socket();
            InetSocketAddress address = new InetSocketAddress(port);

            // 进行服务的绑定
            serverSocket.bind(address);

            // 注册到selector，等待连接
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
            System.out.println("服务器运行，端口：" + port);

            // 数据缓冲区
            ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
            while (true) {
                if ((selector.select()) > 0) {

                    // 选择一组键，并且相应的通道已经准备就绪
                    // 取出全部生成的key
                    Set selectedKeys = selector.selectedKeys();
                    Iterator iter = selectedKeys.iterator();

                    while (iter.hasNext()) {

                        SelectionKey key = iter.next();
                        if (key.isAcceptable()) {
                            acceptable(key, byteBuffer, selector);

                        } else if (key.isReadable() && key.isValid()) {
                            readable(selector, byteBuffer, key);

                        } else if (key.isWritable() && key.isValid()) {
                            writable(selector, byteBuffer, key);
                        }
                    }

                    // 清除全部的key
                    selectedKeys.clear();
                }
            }
        }

        public static void writable(Selector selector, ByteBuffer byteBuffer, SelectionKey key)
                throws IOException, ClosedChannelException {
            SocketChannel client = (SocketChannel) key.channel();
            byteBuffer.clear();

            // 向缓冲区中设置内容
            byteBuffer.put(("欢迎学习NIO教程").getBytes());
            byteBuffer.flip();

            // 输出内容
            client.write(byteBuffer);
            client.register(selector, SelectionKey.OP_READ);
        }

        public static void readable(Selector selector, ByteBuffer byteBuffer, SelectionKey key)
                throws IOException, ClosedChannelException {
            SocketChannel client = (SocketChannel) key.channel();
            byteBuffer.clear();

            // 读取内容到缓冲区中
            int readSize = client.read(byteBuffer);
            if (readSize > 0) {
                System.out.println("服务器端接受客户端数据:" + new String(byteBuffer.array(), 0, readSize));
                client.register(selector, SelectionKey.OP_WRITE);
            }
        }

        public static void acceptable(SelectionKey key, ByteBuffer byteBuffer, Selector selector) throws IOException {
            ServerSocketChannel server = (ServerSocketChannel) key.channel();

            // 接收新连接 和BIO写法类是都是accept
            SocketChannel client = server.accept();
            // 配置为非阻塞
            client.configureBlocking(false);
            byteBuffer.clear();

            // 向缓冲区中设置内容
            byteBuffer.put(("当前的时间为：" + new Date()).getBytes());
            byteBuffer.flip();
            // 输出内容
            client.write(byteBuffer);
            client.register(selector, SelectionKey.OP_READ);
        }
    }

}

客户端

package edu.xcdq;

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

/**
 * @qvthor liuwenzheng
 * @date 2021/5/18 16:16
 */
public class SelectorServiceDemo {


    public static void main(String[] args) throws Exception {
        int port = 8000;
        //通过open()方法找到Selector
        Selector selector = Selector.open();

        //打开服务器的通道
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();

        // 服务器配置为非阻塞
        serverSocketChannel.configureBlocking(false);
        ServerSocket serverSocket = serverSocketChannel.socket();
        InetSocketAddress address = new InetSocketAddress(port);

        //进行服务器绑定
        serverSocket.bind(address);

        //注册到selector,等待链接
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
        System.out.println("服务器运行，端口："+port);

        //数据缓冲区
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
        while (true){
            if (selector.select()>0){

                //选择一组键，并且相应的通道已经准备就绪
                //去除全部生成的key
                Set selectionKeys = selector.selectedKeys();
                Iterator iter = selectionKeys.iterator();
                while (iter.hasNext()){
                    SelectionKey key = iter.next();
                    if (key.isAcceptable()){
                        acceptable(key,byteBuffer,selector);
                    }else if (key.isReadable()&& key.isValid()){
                        readable(selector,byteBuffer,key);
                    }else if (key.isWritable()&& key.isValid()){
                        writable(selector,byteBuffer,key);
                    }
                }
                //清除全部的key
                selectionKeys.clear();;
            }
        }
    }

    public static void writable(Selector selector, ByteBuffer byteBuffer, SelectionKey key)
            throws IOException {
             SocketChannel client =(SocketChannel) key.channel();
            byteBuffer.clear();
            //向缓冲区中设置内容
            byteBuffer.put(("欢迎学习NIO教程").getBytes());
            byteBuffer.flip();
            //输出内容
           client.write(byteBuffer);
            client.register(selector, SelectionKey.OP_READ);

    }
    public static void readable(Selector selector, ByteBuffer byteBuffer, SelectionKey key)
            throws IOException, ClosedChannelException {
        SocketChannel client = (SocketChannel) key.channel();
        byteBuffer.clear();

        // 读取内容到缓冲区中
        int readSize = client.read(byteBuffer);
        if (readSize > 0) {
            System.out.println("服务器端接受客户端数据:" + new String(byteBuffer.array(), 0, readSize));
            client.register(selector, SelectionKey.OP_WRITE);
        }
    }
    public static void acceptable(SelectionKey key, ByteBuffer byteBuffer, Selector selector) throws IOException {
        ServerSocketChannel server = (ServerSocketChannel) key.channel();

        // 接收新连接 和BIO写法类是都是accept
        SocketChannel client = server.accept();
        // 配置为非阻塞
        client.configureBlocking(false);
        byteBuffer.clear();

        // 向缓冲区中设置内容
        byteBuffer.put(("当前的时间为：" + new Date()).getBytes());
        byteBuffer.flip();
        // 输出内容
        client.write(byteBuffer);
        client.register(selector, SelectionKey.OP_READ);
    }
}