BIO NIO AIO之间的区别

 1 import java.io.IOException;
 2 import java.net.InetSocketAddress;
 3 import java.nio.channels.SelectionKey;
 4 import java.nio.channels.Selector;
 5 import java.nio.channels.ServerSocketChannel;
 6 import java.util.Iterator;
 7  
 8 public class TCPServerSelector{
 9     //缓冲区的长度
10     private static final int BUFSIZE = 256;
11     //select方法等待信道准备好的最长时间
12     private static final int TIMEOUT = 3000;
13     public static void main(String[] args) throws IOException {
14         if (args.length < 1){
15             throw new IllegalArgumentException("Parameter(s): <Port> ...");
16         }
17         //创建一个选择器
18         Selector selector = Selector.open();
19         for (String arg : args){
20             //实例化一个信道
21             ServerSocketChannel listnChannel = ServerSocketChannel.open();
22             //将该信道绑定到指定端口
23             listnChannel.socket().bind(new InetSocketAddress(Integer.parseInt(arg)));
24             //配置信道为非阻塞模式
25             listnChannel.configureBlocking(false);
26             //将选择器注册到各个信道
27             listnChannel.register(selector, SelectionKey.OP_ACCEPT);
28         }
29         //创建一个实现了协议接口的对象
30         TCPProtocol protocol = new EchoSelectorProtocol(BUFSIZE);
31         //不断轮询select方法，获取准备好的信道所关联的Key集
32         while (true){
33             //一直等待,直至有信道准备好了I/O操作
34             if (selector.select(TIMEOUT) == 0){
35                 //在等待信道准备的同时，也可以异步地执行其他任务，
36                 //这里只是简单地打印"."
37                 System.out.print(".");
38                 continue;
39             }
40             //获取准备好的信道所关联的Key集合的iterator实例
41             Iterator<SelectionKey> keyIter = selector.selectedKeys().iterator();
42             //循环取得集合中的每个键值
43             while (keyIter.hasNext()){
44                 SelectionKey key = keyIter.next();
45                 //如果服务端信道感兴趣的I/O操作为accept
46                 if (key.isAcceptable()){
47                     protocol.handleAccept(key);
48                 }
49                 //如果客户端信道感兴趣的I/O操作为read
50                 if (key.isReadable()){
51                     protocol.handleRead(key);
52                 }
53                 //如果该键值有效，并且其对应的客户端信道感兴趣的I/O操作为write
54                 if (key.isValid() && key.isWritable()) {
55                     protocol.handleWrite(key);
56                 }
57                 //这里需要手动从键集中移除当前的key
58                 keyIter.remove();
59             }
60         }
61     }
62 }

 1 public static void main(String[] args) throws IOException {
 2  
 3     AsynchronousServerSocketChannel server = AsynchronousServerSocketChannel.open().bind(new InetSocketAddress(0000));
 4     server.accept(null, new CompletionHandler<AsynchronousSocketChannel, Object>() {
 5         final ByteBuffer buffer = ByteBuffer.allocate(1024);
 6  
 7         @Override
 8         public void completed(AsynchronousSocketChannel result, Object attachment) {
 9             System.out.println(Thread.currentThread().getName());
10             Future<Integer> writeResult = null;
11             try {
12                 buffer.clear();
13                 result.read(buffer).get(100, TimeUnit.SECONDS);
14                 buffer.flip();
15                 writeResult = result.write(buffer);
16             } catch (InterruptedException | ExecutionException e) {
17                 e.printStackTrace();
18             } catch (TimeoutException e) {
19                 e.printStackTrace();
20             } finally {
21                 try {
22                     server.accept(null, this);
23                     writeResult.get();
24                     result.close();
25                 } catch (Exception e) {
26                     System.out.println(e.toString());
27                 }
28             }
29         }
30  
31         @Override
32         public void failed(Throwable exc, Object attachment) {
33             System.out.println("failed: " + exc);
34         }
35     });
36  
37 }