Bio、Nio、Aio的用法系列之NIO客户端（三）

public class NioServer {
public static void main(String [] args){
    //启动一个线程
    new Thread(new NioServerHandle()).start();
}

public class NioServerHandle implements Runnable{private ServerSocketChannel serverSocketChannel;
private Selector selector;
boolean stop  = false;
//初始化注册
public NioServerHandle(){
    try {
        //获取ServerSocketChannel对象
        serverSocketChannel = ServerSocketChannel.open();
        //绑定ip
        serverSocketChannel.socket().bind(new InetSocketAddress("127.0.0.1",8989));
        //设置为非阻塞
        serverSocketChannel.configureBlocking(false);
        //获取Selector
        selector = Selector.open();
        //将管道注册到多路复用器selector上
        serverSocketChannel.register(selector,SelectionKey.OP_ACCEPT);
    } catch (IOException e) {
        e.printStackTrace();
        System.exit(1);
    }
}
public void stop(){
    this.stop = true;
}
@Override
public void run() {
    //轮询key
    while (!stop){
        try {
            //设置超时时间
            selector.select(1000);
            //获取所有key
            Set<selectionkey> selectionKeys = selector.selectedKeys();
            //遍历
            Iterator</selectionkey><selectionkey> it = selectionKeys.iterator();
            SelectionKey selectionKey = null;
            while (it.hasNext()){
                selectionKey = it.next();
                //获取到就绪数组进行操作，并移除
                it.remove();
                try {
                    handle(selectionKey);
                }catch (Exception e){
                    selectionKey.cancel();
                    selectionKey.channel().close();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
/**
 * 处理
 * @param key
 * @throws Exception
 */
public void handle(SelectionKey key) throws Exception{
    if (key.isValid()){
        if (key.isAcceptable()){
            //获取ServerSocketChannel
            ServerSocketChannel ssc = (ServerSocketChannel)key.channel();
            //接受请求
            SocketChannel sc = ssc.accept();
            //设置为非阻塞
            sc.configureBlocking(false);
            //注册到多路复用器
            sc.register(selector,SelectionKey.OP_READ);
        }
        //read data
        if (key.isReadable()){
            //得到SocketChannel
            SocketChannel sc = (SocketChannel) key.channel();
            //设置字节缓冲区
            ByteBuffer readBuffer = ByteBuffer.allocate(1024);
            //将通道的数据读取码流
            int readByte = sc.read(readBuffer);
            //对于大于0的情况进行编解码
            if (readByte > 0){
                //将当前的缓冲区的limit设置为0,让后面进行读取
                readBuffer.flip();
                //根据缓冲区的可读大小设置字节数组
                byte [] bytes = new byte[readBuffer.remaining()];
                //get将读取的数据放入字节数组
                readBuffer.get(bytes);
                //将字节数组按照UTF-8的格式输出到body
                String body = new String(bytes,"UTF-8");
                System.out.print("The Time server recevive order:"+body);
                String currentTime = "query".equals(body)?new java.util.Date(System.currentTimeMillis()).toString():"No";
                //进行输出操作
                doWrite(sc,currentTime);
            }else if (readByte < 0 ){
                key.cancel();
                sc.close();
            }else {
            }
        }
    }
}
/**
 * 将数据返回给客户端
 * @param sc
 * @param currentTime
 * @throws Exception
 */
public void doWrite(SocketChannel sc,String currentTime) throws Exception{
    if (currentTime != null && currentTime.trim().length() > 0){
        //转换为字节数组，放到缓冲区
        byte [] bytes = currentTime.getBytes();
        ByteBuffer byteBuffer = ByteBuffer.allocate(bytes.length);
        byteBuffer.put(bytes);
        byteBuffer.flip();
        sc.write(byteBuffer);
    }
}}