【Java】AIO實例

一、blocking/non-blocking | sync/async

1.blocking/non-blocking: 描述的是方法會不會阻塞線程的執行，使線程進入blocking狀態

2.sync/async:描述的是數據讀寫方式

• sync:用戶線程參與數據讀寫
• 由內核線程發起讀寫，用戶只需要關注I/O完成後的回調，不需要參與具體的I/O過程

二、AIO(Asynchronous Input and Output)

1. NIO2.0提出了新異步通道概念，並提供了異步文件通道和異步套接字實現的通道(JDK7)
2. 異步套接字通道真正的實現了真正的異步非阻塞I/O

三、三種IO工作原理

四、AIO模型

五、BIO、NIO、AIO

I/O	數據傳輸	時間	實現方式	使用場景	應用
BIO	Stream	JDK1	Socket	連接數目比較小且固定的架構	一般很少使用
NIO	ByteBuffer	JDK4	Channel Selector	連接數目多且連接比較短（輕操作）的架構	網絡框架netty
AIO	ByteBuffer	JDK7	Channel	連接數目多且連接比較長（重操作）的架構	Ngix,MySQL新版本

六、AIO實現

//TestServer.java
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.AsynchronousServerSocketChannel;
import java.nio.channels.AsynchronousSocketChannel;
import java.nio.channels.CompletionHandler;

public class TestServer {
	
	private AsynchronousServerSocketChannel channel = null;
	
	public TestServer(int port) {
		
		try {
			channel = AsynchronousServerSocketChannel.open().bind(new InetSocketAddress(port));
		} catch (IOException e) {
			e.printStackTrace();
		}

		channel.accept(null, new CompletionHandler<AsynchronousSocketChannel, Void>() {

			@Override
			public void completed(AsynchronousSocketChannel socket, Void attachment) {
				channel.accept(attachment, this);
				ByteBuffer byteBuffer = ByteBuffer.allocate(64);
				socket.read(byteBuffer);
				byteBuffer.flip();
				System.out.println(new String(byteBuffer.array()));
			}

			@Override
			public void failed(Throwable exc, Void attachment) {
				System.out.println("建立通信失敗");
			}
		});
		
	}
	
	
	public static void main(String[] args) {
		new TestServer(9000);
		try {
			Thread.sleep(10000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}


}

//TestClient.java
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.AsynchronousSocketChannel;

public class TestClient {
	
	public static void main(String[] args) throws Exception {
		
		AsynchronousSocketChannel channel = AsynchronousSocketChannel.open();
		
		channel.connect(new InetSocketAddress("127.0.0.1", 9000));
		
		
		ByteBuffer buffer = ByteBuffer.allocate(64);
		
		buffer.put("hello".getBytes());
		
		buffer.flip();
		
		channel.write(buffer);
		
	}

}