NIO经典demo源码

发表于

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package com.test.nio;

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

/**
 * Created by lifei on 16/11/8.
 */
public class NIOServer {
    private int flag = 0;/*标识数字*/
    private int blockSize = 4096;/*缓冲区大小*/
    private ByteBuffer sendBuffer = ByteBuffer.allocate(blockSize);/*接受数据缓冲区*/
    private ByteBuffer receiveBuffer = ByteBuffer.allocate(blockSize);/*发送数据缓冲区*/
    private Selector selector;

    public NIOServer(int port) {
        try {
            ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();// 打开服务器套接字通道
            serverSocketChannel.configureBlocking(false);//// 服务器配置为非阻塞
            ServerSocket serverSocket = serverSocketChannel.socket(); // 检索与此通道关联的服务器套接字
            serverSocket.bind(new InetSocketAddress(port));//绑定ip和端口
            selector = Selector.open();//打开选择器
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);// 注册到selector，等待连接
            System.out.println("Server start -> " + port);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //监听
    public void listen(){
        while (true){
            try {
                selector.select();//如果查询不到,会阻塞      选择一组键，并且相应的通道已经打开
                Set<SelectionKey> selectionKeys = selector.selectedKeys();// 返回此选择器的已选择键集。
                Iterator<SelectionKey> iterator = selectionKeys.iterator();
                while (iterator.hasNext()){
                    SelectionKey selectionKey = iterator.next();
                    iterator.remove();
                    //业务逻辑
                    handleKey(selectionKey);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    // 处理请求
    public void handleKey(SelectionKey selectionKey){
        try {
            // 接受请求
            ServerSocketChannel server;
            SocketChannel client;
            String receiveText;
            String sendText;
            int count;
            if (selectionKey.isAcceptable()){// 测试此键的通道是否已准备好接受新的套接字连接。
                server = (ServerSocketChannel) selectionKey.channel();// 返回为之创建此键的通道。
                client = server.accept();// 接受到此通道套接字的连接。  此方法返回的套接字通道（如果有）将处于阻塞模式。
                client.configureBlocking(false);// 配置为非阻塞
                client.register(selector,SelectionKey.OP_READ);// 注册到selector，等待连接
            } else if (selectionKey.isReadable()){
                client = (SocketChannel) selectionKey.channel();// 返回为之创建此键的通道。
                receiveBuffer.clear();//todo 将缓冲区清空以备下次读取
                count = client.read(receiveBuffer);//读取服务器发送来的数据到缓冲区中
                if (count > 0){
                    receiveText = new String(receiveBuffer.array(),0,count);
                    System.out.println("服务端接收到客户端的信息:"+receiveText);
                    client.register(selector,SelectionKey.OP_WRITE);
                }
            } else if (selectionKey.isWritable()){
                sendBuffer.clear();//将缓冲区清空以备下次写入
                client = (SocketChannel) selectionKey.channel();// 返回为之创建此键的通道。
                sendText = "msg send to clent ..."+(flag++);//发送的数据
                sendBuffer.put(sendText.getBytes());//向缓冲区中输入数据
                sendBuffer.flip();//将缓冲区各标志复位,因为向里面put了数据标志被改变要想从中读取数据发向服务器,就要复位
                client.write(sendBuffer);//输出到通道
                System.out.println("服务端发送数据给客户端:"+sendText);
                client.register(selector,SelectionKey.OP_READ);
            }
        } catch (Exception e){
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        int port = 7080;
        NIOServer server = new NIOServer(port);
        server.listen();
    }


}
```    

# client:    

```java
package com.test.nio;

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

/**
 * Created by lifei on 16/11/8.
 * http://developer.51cto.com/art/201112/307685.htm
 */
public class NIOClient {
    private static int flag = 0;/*标识数字*/
    private static int blockSize = 4096;/*缓冲区大小*/
    private static ByteBuffer sendBuffer = ByteBuffer.allocate(blockSize);/*接受数据缓冲区*/
    private static ByteBuffer receiveBuffer = ByteBuffer.allocate(blockSize); /*服务器端地址*/
    private final static InetSocketAddress serverAddress = new InetSocketAddress("127.0.0.1",7080);

    public static void main(String[] args) {
        try {
            SocketChannel socketChannel = SocketChannel.open();// 打开socket通道
            socketChannel.configureBlocking(false);// 设置为非阻塞方式
            Selector selector = Selector.open();//打开选择器
            socketChannel.register(selector, SelectionKey.OP_CONNECT);// 注册连接服务端socket动作
            socketChannel.connect(serverAddress);// 连接

            // 分配缓冲区大小内存
            Set<SelectionKey> selectionKeys;
            Iterator<SelectionKey> iterator;
            SelectionKey selectionKey;
            SocketChannel client;
            String receiveText;
            String sendText;
            int count;

            while (true){
                try {
                    selector.select();//todo 选择一组键，其相应的通道已为 I/O 操作准备就绪。 此方法执行处于阻塞模式的选择操作。
                    selectionKeys = selector.selectedKeys();//返回此选择器的已选择键集。
                    iterator = selectionKeys.iterator();
                    while (iterator.hasNext()){
                        selectionKey = iterator.next();
                        if (selectionKey.isConnectable()){
                            System.out.println("client connet");
                            client = (SocketChannel) selectionKey.channel();
                            if (client.isConnectionPending()){// 判断此通道上是否正在进行连接操作。  完成套接字通道的连接过程。
                                client.finishConnect();
                                System.out.println("客户端完成连接操作");
                                sendBuffer.clear();
                                sendText = "Hello server...";
                                sendBuffer.put(sendText.getBytes());
                                sendBuffer.flip();
                                client.write(sendBuffer);
                            }
                            client.register(selector,SelectionKey.OP_READ);
                        } else if (selectionKey.isReadable()){
                            client = (SocketChannel) selectionKey.channel();
                            receiveBuffer.clear();//将缓冲区清空以备下次读取
                            count = client.read(receiveBuffer);//读取服务器发送来的数据到缓冲区中
                            if (count > 0){
                                receiveText = new String(receiveBuffer.array(),0,count);
                                System.out.println("客户端接收到服务端数据:"+receiveText);
                                client.register(selector,SelectionKey.OP_WRITE);
                            }
                        } else if (selectionKey.isWritable()){
                            sendBuffer.clear();
                            client = (SocketChannel) selectionKey.channel();
                            sendText = "Msg to server ..."+(flag++);
                            sendBuffer.put(sendText.getBytes());
                            sendBuffer.flip();//将缓冲区各标志复位,因为向里面put了数据标志被改变要想从中读取数据发向服务器,就要复位
                            client.write(sendBuffer);
                            System.out.println("客户端发送数据给服务端"+sendText);
                            client.register(selector,SelectionKey.OP_READ);
                        }
                    }
                    selectionKeys.clear();
                } catch (Exception e){

                }

            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}