AsyncWeb原理分析(三)——Mina的IoHandler

    此文分析AsyncWeb如何和Mina的IoHandler結合的

一般的mina server類：

主類如下：

   IoAcceptor acceptor = new NioSocketAcceptor();   acceptor.getFilterChain().addLast("logger", new LoggingFilter());   acceptor.getFilterChain().addLast(     "codec",     new ProtocolCodecFilter(new TextLineCodecFactory(Charset       .forName("UTF-8"))));   acceptor.setHandler(new TimeServerHandler());   acceptor.getSessionConfig().setReadBufferSize(2048);   acceptor.getSessionConfig().setIdleTime(IdleStatus.BOTH_IDLE, 10);   acceptor.bind(new InetSocketAddress(8080));

TimeServerHandler類如下：

public class TimeServerHandler extends IoHandlerAdapter {@Overridepublic void exceptionCaught(IoSession session, Throwable cause)    throws Exception {   cause.printStackTrace();}@Overridepublic void messageReceived(IoSession session, Object message)    throws Exception {   String str = message.toString();   System.out.println("Message read:");   System.out.println(str);   Date date = new Date();   session.write(date.toString());   System.out.println("Message written...");   session.close();}@Overridepublic void sessionIdle(IoSession session, IdleStatus status)    throws Exception {   System.out.println("IDLE " + session.getIdleCount(status));}}

    一般的流程：初始化NioSocketAcceptor——》增加Filter——》設定Handler——》設定session屬性——》bind（）就可以了。啟動後，通過TimeServerHandler從IoHandlerAdapter 裡面的繼承的方法，處理資料。

Asyncweb中的方式：

MinaTransport類中的start（）

package org.apache.asyncweb.server.transport.minapublic void start() throws TransportException {ioHandler = new DefaultHttpIoHandler();ioHandler.setContainer( container );acceptor = new NioSocketAcceptor(ioThreads);eventExecutor = new OrderedThreadPoolExecutor(this.eventThreads);boolean success = false;try {DefaultIoFilterChainBuilder chain = acceptor.getFilterChain();chain.addFirst("threadPool", new ExecutorFilter(eventExecutor));acceptor.setReuseAddress(true);acceptor.getSessionConfig().setReuseAddress(true);chain.addLast("mdc", new MdcInjectionFilter());if (isLoggingTraffic) {LOG.debug("Configuring traffic logging filter");LoggingFilter filter = new LoggingFilter();filter.setSessionClosedLogLevel(logLevel);filter.setExceptionCaughtLogLevel(logLevel);filter.setMessageReceivedLogLevel(logLevel);filter.setMessageSentLogLevel(logLevel);filter.setSessionClosedLogLevel(logLevel);filter.setSessionCreatedLogLevel(logLevel);filter.setSessionIdleLogLevel(logLevel);filter.setSessionOpenedLogLevel(logLevel);acceptor.getFilterChain().addLast("logging", filter);}// TODO make this configurable instead of hardcoding like thisacceptor.setBacklog(100);acceptor.setHandler(ioHandler);if (address != null) {acceptor.bind(new InetSocketAddress(address, port));} else {acceptor.bind(new InetSocketAddress(port));}success = true;LOG.debug("NIO HTTP Transport bound on port " + port);} catch (IOException e) {throw new TransportException("NIOTransport Failed to bind to port "+ port, e);} finally {if (!success) {acceptor.dispose();acceptor = null;}}}

package org.apache.asyncweb.server.transport.mina;public class DefaultHttpIoHandler extends SingleSessionIoHandlerDelegate implements HttpIoHandler{    /** the default idle time in seconds - 5 minutes */    public static final int DEFAULT_IDLE_TIME = 300;    public DefaultHttpIoHandler()    {        super( new Factory() );//父類的建構函式，參數必須實現SingleSessionIoHandlerFactory 這個介面    }    //實現了HttpIoHandler 裡的setContainer（）    public ServiceContainer getContainer()    {        return ( ( Factory ) getFactory() ).getContainer();    }    public void setContainer( ServiceContainer container )    {        ( ( Factory ) getFactory() ).setContainer( container );    }    public void setReadIdle( int idleTime )    {        ( ( Factory ) getFactory() ).setReadIdle( idleTime );    }    //產生SingleSessionIoHandler的Factory 方法，而SingleSessionIoHandler是用來處理特定session的。    private static class Factory implements SingleSessionIoHandlerFactory    {        private ServiceContainer container;        private int readIdleTime = DEFAULT_IDLE_TIME;        public ServiceContainer getContainer()        {            return container;        }        public void setContainer( ServiceContainer container )        {            this.container = container;        }        public void setReadIdle( int idleTime )        {            this.readIdleTime = idleTime;        }        ////實現了SingleSessionIoHandlerFactory 的getHandler方法，        public SingleSessionIoHandler getHandler( IoSession session )        {            SingleHttpSessionIoHandler handler = new SingleHttpSessionIoHandler( container, session );            handler.setReadIdleTime( readIdleTime );            return handler;        }    }}

類圖：

總結：通過DefaultHttpIoHandler的處理，最終產生了IoHandler的實作類別SingleHttpSessionIoHandler，

其中包含3個攝入的對象ServiceContainer，IoSession，readIdleTime。

資料的處理都是通過Filter的責任鏈來處理。

因為先要解析Http，並跳轉到正確的HttpService。

下期預告：《AsyncWeb原理分析(四)——http的解析》