Java，Java NIO，Java NIO2，Java AIO，AsynchronousServerSocketChannel

Server.java

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| import java.io.IOException; import java.net.InetSocketAddress; import java.nio.channels.AsynchronousChannelGroup; import java.nio.channels.AsynchronousServerSocketChannel; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.TimeUnit; /** * @author Bright Lee */ public final class Server { private final Configuration configuration; private final ExecutorService pool; private final AsynchronousChannelGroup group; private final AsynchronousServerSocketChannel serverChannel; public Server() { configuration = new Configuration(); try { pool = Executors.newFixedThreadPool (4); group = AsynchronousChannelGroup.withThreadPool (pool); serverChannel = AsynchronousServerSocketChannel.open (group) .bind(new InetSocketAddress(configuration.getPort())); } catch (IOException e) { throw new RuntimeException(e); } } public void startup() { serverChannel.accept(null, new AcceptCompletionHandler(serverChannel, configuration.getReadBufferSize())); try { group.awaitTermination(Long.MAX_VALUE , TimeUnit.SECONDS ); } catch (InterruptedException e) { throw new RuntimeException(e); } } public void shutdown() { try { serverChannel.close(); } catch (IOException e) { throw new RuntimeException(e); } finally { try { group.shutdown(); } catch (Exception e) { throw new RuntimeException(e); } finally { try { pool.shutdown(); } catch (Exception e) { throw new RuntimeException(e); } } } } } |

AcceptCompletionHandler.java

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| import java.nio.channels.AsynchronousServerSocketChannel; import java.nio.channels.AsynchronousSocketChannel; import java.nio.channels.CompletionHandler; /** * @author Bright Lee */ public final class AcceptCompletionHandler implements CompletionHandler<AsynchronousSocketChannel, Void> { private final AsynchronousServerSocketChannel serverChannel; private final int readBufferSize; public AcceptCompletionHandler(AsynchronousServerSocketChannel serverChannel, int readBufferSize) { this.serverChannel = serverChannel; this.readBufferSize = readBufferSize; } @Override public void completed(AsynchronousSocketChannel clientChannel, Void attachment) { // 必须：立即再次发起 accept ，以便接受后续连接 if (serverChannel.isOpen()) { serverChannel.accept(null, new AcceptCompletionHandler(serverChannel, readBufferSize)); } // 为当前客户端连接启动异步读取 ReadCompletionHandler readCompletionHandler = new ReadCompletionHandler(clientChannel, readBufferSize); clientChannel.read(readCompletionHandler.getReadAttachment(), readCompletionHandler.getReadAttachment(), readCompletionHandler); } @Override public void failed(Throwable e, Void attachment) { e.printStackTrace(); } } |

ReadCompletionHandler.java

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| import java.io.IOException; import java.nio.ByteBuffer; import java.nio.channels.AsynchronousSocketChannel; import java.nio.channels.CompletionHandler; /** * @author Bright Lee */ public final class ReadCompletionHandler implements CompletionHandler<Integer, ByteBuffer> { private final AsynchronousSocketChannel clientChannel; private final ByteBuffer readAttachment; private final WriteCompletionHandler writeCompletionHandler; public ReadCompletionHandler(AsynchronousSocketChannel clientChannel, int readBufferSize) { this.clientChannel = clientChannel; this.readAttachment = ByteBuffer.allocate (readBufferSize); this.writeCompletionHandler = new WriteCompletionHandler(this); } AsynchronousSocketChannel getClientChannel() { return clientChannel; } ByteBuffer getReadAttachment() { return readAttachment; } @Override public void completed(Integer result, ByteBuffer readAttachment) { // 翻转缓冲区，准备读取数据 readAttachment.flip(); byte\[\] data = new byte $readAttachment.remaining()$ ; readAttachment.get(data); String message = new String(data).toUpperCase(); System.out .println("收到并处理: " + message); // 异步写回响应 readAttachment.clear(); clientChannel.write(ByteBuffer.wrap (message.getBytes()), null, writeCompletionHandler); } @Override public void failed(Throwable t, ByteBuffer buf) { t.printStackTrace(); try { clientChannel.close(); } catch (IOException e) { e.printStackTrace(); } } } |

WriteCompletionHandler.java

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| import java.io.IOException; import java.nio.ByteBuffer; import java.nio.channels.AsynchronousSocketChannel; import java.nio.channels.CompletionHandler; /** * @author Bright Lee */ public final class WriteCompletionHandler implements CompletionHandler<Integer, Void> { private final AsynchronousSocketChannel clientChannel; private final ByteBuffer writeAttachment; private final ReadCompletionHandler readCompletionHandler; public WriteCompletionHandler(ReadCompletionHandler readCompletionHandler) { this.clientChannel = readCompletionHandler.getClientChannel(); this.writeAttachment = ByteBuffer.allocate (1024); this.readCompletionHandler = readCompletionHandler; } AsynchronousSocketChannel getClientChannel() { return clientChannel; } ByteBuffer getWriteAttachment() { return writeAttachment; } @Override public void completed(Integer result, Void attachment) { // 写完后，清空缓冲区，继续读取下一条消息 final ByteBuffer readAttachment = readCompletionHandler.getReadAttachment(); readAttachment.clear(); clientChannel.read(readAttachment, readAttachment, readCompletionHandler); } @Override public void failed(Throwable t, Void attachment) { t.printStackTrace(); try { clientChannel.close(); } catch (IOException e) { e.printStackTrace(); } } } |

Nio2ServerTest.java

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| /** * @author Bright Lee */ public final class Nio2ServerTest { public static void main(String\[\] args) { Server server = new Server(); server.startup(); } } |

Nio2ClientTest.java