一般Socket客户端与Mina NIO Socket客户端对比示例
在看Mina源代码时发现其客户端Socket Connector的例子很少，耗费了我一些时间。相对传统IO的堵塞式，NIO 的优势和特色就在于非堵塞了。使用NIO的话，不管是服务器端还是客户端，都不用堵住了。这样就大大提高了服务处理的能力，也减少了等待的时间。当然，传统IO Socket编程通常都会使用一个专有线程监听连接请求，获悉新请求后产生其它线程来服务该连接。不管怎么样，这些服务都是同步操作。NIO就不一样了，什么都是通知的。打个比方，就像一个客人到商店预订商品，当商品齐全了，店长就可以将商品发送给客人，或者通知客人取货了。由于采取了NIO，所以使用Mina时一定要有异步消息处理思想。这里提供一个简单的例子服务器端用传统IO 的ServerSocket，收到新请求后只是返回一个消息：
try { Socket socket = this.serverSocket.accept(); InputStream is = socket.getInputStream(); DataInputStream dis = new DataInputStream(is); if(dis.read(bytes) < 1024) { System.out.println(new String(bytes)); } OutputStream os = socket.getOutputStream(); os.write(("This is server, your reservation number:["+i+"]").getBytes()); os.write(("\nAnything i can help?").getBytes()); os.flush(); os.close(); is.close(); socket.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); }
传统Socket客户端实现：
public void request(byte [] reequest, ResponseHandler handler) { if(!socket.isConnected()){ throw new IllegalStateException("Socket not connected to["+address+":"+port+"]."); } OutputStream os = null; InputStream is = null; DataInputStream dis = null; try { os = this.socket.getOutputStream(); os.write(reequest); os.flush(); is = this.socket.getInputStream(); dis = new DataInputStream(is); ByteArrayOutputStream baos = new ByteArrayOutputStream(); byte [] bytes = new byte; int len = 0; while((len = dis.read(bytes)) != -1) { baos.write(bytes, 0, len); } handler.handleResponse(baos.toByteArray()); } catch (IOException e) { }finally { try { dis.close(); } catch (IOException e) { } try { os.close(); } catch (IOException e) { } try { this.socket.close(); } catch (IOException e) { } } }
Mina的Socket Connector方式：
public void test1() { try { final StringBuffer buf = new StringBuffer(); SocketConnector connector = new SocketConnector(); ConnectFuture future = connector.connect(new InetSocketAddress( "localhost", 9999), new IoHandlerAdapter() { public void sessionCreated(IoSession session) { log.debug("Session Created"); buf.append("1"); } public void sessionOpened(IoSession session) { log.debug("Session Opened"); WriteFuture writeFuture = session.write(ByteBuffer.wrap("Hello".getBytes())); writeFuture.join(); } public void exceptionCaught(IoSession session, Throwable cause) { log.debug("Exception,", cause); buf.append("X"); } @Override public void messageReceived(IoSession session, Object message) throws Exception { if(message instanceof ByteBuffer) { ByteBuffer byteb = (ByteBuffer)message; ByteArrayOutputStream baos = new ByteArrayOutputStream(); byte[] bytearray = new byte; while(byteb.hasRemaining()) { int len = Math.min(byteb.remaining(), 1024); byteb.get(bytearray,0, len); baos.write(bytearray, 0, len); } log.debug("Message from Server:" + new String(baos.toByteArray())); } } @Override public void messageSent(IoSession session, Object message) throws Exception { log.debug("Sent:" + message); } @Override public void sessionClosed(IoSession session) throws Exception { log.debug("Session closed."); super.sessionClosed(session); } @Override public void sessionIdle(IoSession session, IdleStatus status) throws Exception { // TODO Auto-generated method stub super.sessionIdle(session, status); } }); log.debug("connect future join begin.");//等待连接准备 future.join(); log.debug("connect future join end."); CloseFuture closeFuture = future.getSession().close(); log.debug("close future join begin."); closeFuture.join(); log.debug("close future join end."); }catch(Exception e) { e.printStackTrace(); } }
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