从入门到精通IO模型：长连接、短连接与Java中的IO模型详解

// 客户端代码
try (Socket socket = new Socket("localhost", 8080)) {
OutputStream outputStream = socket.getOutputStream();
    outputStream.write("Hello World".getBytes());
} catch (IOException e) {
    e.printStackTrace();
}
// 服务端代码
try (ServerSocket serverSocket = new ServerSocket(8080)) {
while (true) {
try (Socket socket = serverSocket.accept()) {
InputStream inputStream = socket.getInputStream();
byte[] bytes = new byte[1024];
int len;
while ((len = inputStream.read(bytes)) != -1) {
                System.out.println(new String(bytes, 0, len));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
} catch (IOException e) {
    e.printStackTrace();
}

// 服务端代码
try (ServerSocketChannel serverSocketChannel = ServerSocketChannel.open()) {
    serverSocketChannel.socket().bind(new InetSocketAddress(8080));
    serverSocketChannel.configureBlocking(false);
Selector selector = Selector.open();
    serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
while (true) {
        selector.select();
        Set<SelectionKey> selectionKeys = selector.selectedKeys();
        Iterator<SelectionKey> iterator = selectionKeys.iterator();
while (iterator.hasNext()) {
SelectionKey selectionKey = iterator.next();
            iterator.remove();
if (selectionKey.isAcceptable()) {
SocketChannel socketChannel = serverSocketChannel.accept();
                socketChannel.configureBlocking(false);
                socketChannel.register(selector, SelectionKey.OP_READ);
            } else if (selectionKey.isReadable()) {
SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
int len;
while ((len = socketChannel.read(byteBuffer)) > 0) {
                    byteBuffer.flip();
                    System.out.println(new String(byteBuffer.array(), 0, len));
                    byteBuffer.clear();
                }
            }
        }
    }
} catch (IOException e) {
    e.printStackTrace();
}
// 客户端代码
try (SocketChannel socketChannel = SocketChannel.open()) {
    socketChannel.connect(new InetSocketAddress("localhost", 8080));
ByteBuffer byteBuffer = ByteBuffer.wrap("Hello World".getBytes());
    socketChannel.write(byteBuffer);
    byteBuffer.clear();
} catch (IOException e) {
    e.printStackTrace();
}

// 服务端代码
try (AsynchronousServerSocketChannel asynchronousServerSocketChannel = AsynchronousServerSocketChannel.open()) {
    asynchronousServerSocketChannel.bind(new InetSocketAddress(8080));
    asynchronousServerSocketChannel.accept(null, new CompletionHandler<AsynchronousSocketChannel, Void>() {
@Override
public void completed(AsynchronousSocketChannel asynchronousSocketChannel, Void attachment) {
ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
            asynchronousSocketChannel.read(byteBuffer, byteBuffer, new CompletionHandler<Integer, ByteBuffer>() {
@Override
public void completed(Integer result, ByteBuffer attachment) {
                    attachment.flip();
byte[] bytes = new byte[attachment.remaining()];
                    attachment.get(bytes);
                    System.out.println(new String(bytes));
// 继续读取数据
                    attachment.clear();
                    asynchronousSocketChannel.read(attachment, attachment, this);
                }
@Override
public void failed(Throwable exc, ByteBuffer attachment) {
                    exc.printStackTrace();
                }
            });
// 继续接受新的连接
            asynchronousServerSocketChannel.accept(null, this);
        }
@Override
public void failed(Throwable exc, Void attachment) {
            exc.printStackTrace();
        }
    });
} catch (IOException e) {
    e.printStackTrace();
}
// 客户端代码
try (AsynchronousSocketChannel asynchronousSocketChannel = AsynchronousSocketChannel.open()) {
    Future<Void> future = asynchronousSocketChannel.connect(new InetSocketAddress("localhost", 8080));
    future.get(); // 等待连接完成
ByteBuffer byteBuffer = ByteBuffer.wrap("Hello World".getBytes());
    asynchronousSocketChannel.write(byteBuffer).get(); // 等待写入完成
} catch (IOException | InterruptedException | ExecutionException e) {
    e.printStackTrace();
}