NP-12-多路复用NIO示例

Server端

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package bhz.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.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;

public class Server implements Runnable{
//1 多路复用器(管理所有的通道)
private Selector seletor;
//2 建立缓冲区
private ByteBuffer readBuf = ByteBuffer.allocate(1024);
//3
private ByteBuffer writeBuf = ByteBuffer.allocate(1024);
public Server(int port){
try {
//1 打开路复用器
this.seletor = Selector.open();
//2 打开服务器通道
ServerSocketChannel ssc = ServerSocketChannel.open();
//3 设置服务器通道为非阻塞模式
ssc.configureBlocking(false);
//4 绑定地址
ssc.bind(new InetSocketAddress(port));
//5 把服务器通道注册到多路复用器上,并且监听阻塞事件
ssc.register(this.seletor, SelectionKey.OP_ACCEPT);

System.out.println("Server start, port :" + port);

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

@Override
public void run() {
while(true){
try {
//1 必须要让多路复用器开始监听
this.seletor.select();
//2 返回多路复用器已经选择的结果集
Iterator<SelectionKey> keys = this.seletor.selectedKeys().iterator();
//3 进行遍历
while(keys.hasNext()){
//4 获取一个选择的元素
SelectionKey key = keys.next();
//5 直接从容器中移除就可以了
keys.remove();
//6 如果是有效的
if(key.isValid()){
//7 如果为阻塞状态
if(key.isAcceptable()){
this.accept(key);
}
//8 如果为可读状态
if(key.isReadable()){
this.read(key);
}
//9 写数据
if(key.isWritable()){
//this.write(key); //ssc
}
}

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

private void write(SelectionKey key){
//ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
//ssc.register(this.seletor, SelectionKey.OP_WRITE);
}

private void read(SelectionKey key) {
try {
//1 清空缓冲区旧的数据
this.readBuf.clear();
//2 获取之前注册的socket通道对象
SocketChannel sc = (SocketChannel) key.channel();
//3 读取数据
int count = sc.read(this.readBuf); //将sc中的数据读到readBuf中
//4 如果没有数据
if(count == -1){
key.channel().close();
key.cancel();
return;
}
//5 有数据则进行读取 读取之前需要进行复位方法(把position 和limit进行复位)
this.readBuf.flip();
//6 根据缓冲区的数据长度创建相应大小的byte数组,接收缓冲区的数据
byte[] bytes = new byte[this.readBuf.remaining()];
//7 接收缓冲区数据
this.readBuf.get(bytes);//把readBuf中的数据存到bytes[]中
//8 打印结果
String body = new String(bytes).trim();
System.out.println("Server : " + body);

// 9..可以写回给客户端数据

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

}

private void accept(SelectionKey key) {
try {
//1 获取服务通道
ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
//2 执行阻塞方法
SocketChannel sc = ssc.accept(); //sc为client的channel
//3 设置阻塞模式
sc.configureBlocking(false);
//4 注册到多路复用器上,并设置读取标识
sc.register(this.seletor, SelectionKey.OP_READ);
} catch (IOException e) {
e.printStackTrace();
}
}

public static void main(String[] args) {

new Thread(new Server(8765)).start();;
}
}

客户端

  • 测试:在console中,输入需发送的消息,回车发送消息到server
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    package bhz.nio;

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

    public class Client {

    //需要一个Selector
    public static void main(String[] args) {

    //创建连接的地址
    InetSocketAddress address = new InetSocketAddress("127.0.0.1", 8765);

    //声明连接通道
    SocketChannel sc = null;

    //建立缓冲区
    ByteBuffer buf = ByteBuffer.allocate(1024);

    try {
    //打开通道
    sc = SocketChannel.open();
    //进行连接
    sc.connect(address);

    while(true){
    //定义一个字节数组,然后使用系统录入功能:
    byte[] bytes = new byte[1024];
    System.in.read(bytes);

    //把数据放到缓冲区中
    buf.put(bytes);
    //对缓冲区进行复位
    buf.flip();
    //写出数据
    sc.write(buf);
    //清空缓冲区数据
    buf.clear();
    }
    } catch (IOException e) {
    e.printStackTrace();
    } finally {
    if(sc != null){
    try {
    sc.close();
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    }

    }

    }