NIO系列-04-AIO

声明

该系列文章由书籍《Netty权威指南》第二版整理而来。只为记录学习笔记。
若认为内容侵权请及时通知本人删除相关内容。

[TOC]

时间服务器–AIO

服务端代码

服务端主程序

public class TimeServer {

	public static void main(String[] args) throws IOException {
		int port = 1234;
		new Thread(new TimeServerHandler(port)).start();
	}
}

服务端处理程序

public class TimeServerHandler implements Runnable {

	private int port;

	private CountDownLatch latch;
	private AsynchronousServerSocketChannel asynchronousServerSocketChannel;

	public TimeServerHandler(int port) {
		this.port = port;
		try {
			this.asynchronousServerSocketChannel = AsynchronousServerSocketChannel.open();
			this.asynchronousServerSocketChannel.bind(new InetSocketAddress(this.port));
			System.out.println("The time server is listening in port : " + this.port);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void run() {

		this.latch = new CountDownLatch(1);
		doAccept();
		try {
			this.latch.await();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}

	private void doAccept() {
		this.asynchronousServerSocketChannel.accept(this,
				new CompletionHandler<AsynchronousSocketChannel, TimeServerHandler>() {

					@Override
					public void completed(AsynchronousSocketChannel result, TimeServerHandler attachment) {
						attachment.asynchronousServerSocketChannel.accept(attachment, this);
						ByteBuffer buffer = ByteBuffer.allocate(1024);
						result.read(buffer, buffer, new TimeServerReadCompletionHandler(result));
					}

					@Override
					public void failed(Throwable exc, TimeServerHandler attachment) {
						exc.printStackTrace();
						attachment.latch.countDown();
					}
				});
	}

//	public AsynchronousServerSocketChannel getAsynchronousServerSocketChannel() {
//		return asynchronousServerSocketChannel;
//	}
//
//	public void setAsynchronousServerSocketChannel(AsynchronousServerSocketChannel asynchronousServerSocketChannel) {
//		this.asynchronousServerSocketChannel = asynchronousServerSocketChannel;
//	}
//
//	public CountDownLatch getLatch() {
//		return latch;
//	}
//
//	public void setLatch(CountDownLatch latch) {
//		this.latch = latch;
//	}

}

服务端处理程序

public class TimeServerReadCompletionHandler implements CompletionHandler<Integer, ByteBuffer> {

	private AsynchronousSocketChannel channel;
	private DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

	public TimeServerReadCompletionHandler(AsynchronousSocketChannel channel) {
		if (this.channel == null)
			this.channel = channel;
	}

	@Override
	public void completed(Integer result, ByteBuffer attachment) {
		attachment.flip();
		byte[] body = new byte[attachment.remaining()];
		attachment.get(body);
		try {
			String req = new String(body, "UTF-8");
			System.out.println("request msg is : " + req);
			doWrite(this.df.format(new Date()));
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
	}

	private void doWrite(String currentTime) {
		if (currentTime != null && currentTime.trim().length() > 0) {
			byte[] bytes = (currentTime).getBytes();
			ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
			writeBuffer.put(bytes);
			writeBuffer.flip();
			channel.write(writeBuffer, writeBuffer, new CompletionHandler<Integer, ByteBuffer>() {
				@Override
				public void completed(Integer result, ByteBuffer buffer) {
					if (buffer.hasRemaining())
						channel.write(buffer, buffer, this);
				}

				@Override
				public void failed(Throwable exc, ByteBuffer attachment) {
					try {
						channel.close();
					} catch (IOException e) {
					}
				}
			});
		}
	}

	@Override
	public void failed(Throwable exc, ByteBuffer attachment) {
		try {
			this.channel.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}

客户端代码

客户端主程序

public class TimeClient {

	public static void main(String[] args) {
		int port = 1234;
		new Thread(new TimeClientHandler("127.0.0.1", port)).start();
	}
}

客户端处理类

public class TimeClientHandler implements CompletionHandler<Void, TimeClientHandler>, Runnable {

	private AsynchronousSocketChannel asc;
	private String host;
	private int port;
	private CountDownLatch latch;

	public TimeClientHandler(String host, int port) {
		this.host = host;
		this.port = port;
		try {
			this.asc = AsynchronousSocketChannel.open();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void run() {

		latch = new CountDownLatch(1);
		asc.connect(new InetSocketAddress(host, port), this, this);
		try {
			latch.await();
		} catch (InterruptedException e1) {
			e1.printStackTrace();
		}
		try {
			asc.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Override
	public void completed(Void result, TimeClientHandler attachment) {
		byte[] req = "Hi Server !".getBytes();
		ByteBuffer writeBuffer = ByteBuffer.allocate(req.length);
		writeBuffer.put(req);
		writeBuffer.flip();
		asc.write(writeBuffer, writeBuffer, new CompletionHandler<Integer, ByteBuffer>() {
			@Override
			public void completed(Integer result, ByteBuffer buffer) {
				if (buffer.hasRemaining()) {
					asc.write(buffer, buffer, this);
				} else {
					ByteBuffer readBuffer = ByteBuffer.allocate(1024);
					asc.read(readBuffer, readBuffer, new CompletionHandler<Integer, ByteBuffer>() {
						@Override
						public void completed(Integer result, ByteBuffer buffer) {
							buffer.flip();
							byte[] bytes = new byte[buffer.remaining()];
							buffer.get(bytes);
							String body;
							try {
								body = new String(bytes, "UTF-8");
								System.out.println("Now is : " + body);
								latch.countDown();
							} catch (UnsupportedEncodingException e) {
								e.printStackTrace();
							}
						}

						@Override
						public void failed(Throwable exc, ByteBuffer attachment) {
							try {
								asc.close();
								latch.countDown();
							} catch (IOException e) {
							}
						}
					});
				}
			}

			@Override
			public void failed(Throwable exc, ByteBuffer attachment) {
				try {
					asc.close();
					latch.countDown();
				} catch (IOException e) {
				}
			}
		});
	}

	@Override
	public void failed(Throwable exc, TimeClientHandler attachment) {
		exc.printStackTrace();
		try {
			asc.close();
			latch.countDown();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}

总结

这种AIO模型有如下特点:

• 代码复杂
• 调试困难

参考资料: 《Netty权威指南》第二版