RabbitMQ学习之ConntectionFactory与Conntection的认知

在发送和接收消息重要的类有：ConnectionFactory， Connection，Channel和 QueueingConsumer。

ConntectionFactory类是方便创建与AMQP代理相关联的Connection；下面来看看ConntectionFactory是如何创建一个Contention.首先通过new ConnectionFactory()创建一个ConnectionFactory；并设置此连接工厂的主机设置为broke IP。通过ConnectionFactory的newConnection()方法 创建一个Connection; newConnection方法通过得到当前连接的地址及端口号来获得一个Address，通过createFrameHandler的方法 来得到FrameHandler;再通过new AMQConnection(this, frameHandler)来得到Connection并启动。
    代码清单1创建Connection的源码（ConnectionFactory.java中）

protected FrameHandler createFrameHandler(Address addr)        throws IOException {        String hostName = addr.getHost();//获取主机IP        int portNumber = portOrDefault(addr.getPort());//获取端口        Socket socket = null;        try {            socket = factory.createSocket();            configureSocket(socket);            socket.connect(new InetSocketAddress(hostName, portNumber),                    connectionTimeout);            return createFrameHandler(socket);        } catch (IOException ioe) {            quietTrySocketClose(socket);            throw ioe;        }    }    private static void quietTrySocketClose(Socket socket) {        if (socket != null)            try { socket.close(); } catch (Exception _) {/*ignore exceptions*/}    }    protected FrameHandler createFrameHandler(Socket sock)        throws IOException    {        return new SocketFrameHandler(sock);    }    /**     *  Provides a hook to insert custom configuration of the sockets     *  used to connect to an AMQP server before they connect.     *     *  The default behaviour of this method is to disable Nagle's     *  algorithm to get more consistently low latency.  However it     *  may be overridden freely and there is no requirement to retain     *  this behaviour.     *     *  @param socket The socket that is to be used for the Connection     */    protected void configureSocket(Socket socket) throws IOException{        // disable Nagle's algorithm, for more consistently low latency        socket.setTcpNoDelay(true);    }    /**     * Create a new broker connection     * @param addrs an array of known broker addresses (hostname/port pairs) to try in order     * @return an interface to the connection     * @throws IOException if it encounters a problem     */    public Connection newConnection(Address[] addrs) throws IOException {        return newConnection(null, addrs);    }    /**     * Create a new broker connection     * @param executor thread execution service for consumers on the connection     * @param addrs an array of known broker addresses (hostname/port pairs) to try in order     * @return an interface to the connection     * @throws IOException if it encounters a problem     */    public Connection newConnection(ExecutorService executor, Address[] addrs)        throws IOException    {        IOException lastException = null;        for (Address addr : addrs) {            try {                FrameHandler frameHandler = createFrameHandler(addr);                AMQConnection conn =                    new AMQConnection(username,                                      password,                                      frameHandler,                                      executor,                                      virtualHost,                                      getClientProperties(),                                      requestedFrameMax,                                      requestedChannelMax,                                      requestedHeartbeat,                                      saslConfig);                conn.start();                return conn;            } catch (IOException e) {                lastException = e;            }        }        throw (lastException != null) ? lastException                                      : new IOException("failed to connect");    }    /**     * Create a new broker connection     * @return an interface to the connection     * @throws IOException if it encounters a problem     */    public Connection newConnection() throws IOException {        return newConnection(null,                             new Address[] {new Address(getHost(), getPort())}                            );    }    /**     * Create a new broker connection     * @param executor thread execution service for consumers on the connection     * @return an interface to the connection     * @throws IOException if it encounters a problem     */    public Connection newConnection(ExecutorService executor) throws IOException {        return newConnection(executor,                             new Address[] {new Address(getHost(), getPort())}                            );    }

  代码清单2 连接启动

/**     * Start up the connection, including the MainLoop thread.     * Sends the protocol     * version negotiation header, and runs through     * Connection.Start/.StartOk, Connection.Tune/.TuneOk, and then     * calls Connection.Open and waits for the OpenOk. Sets heart-beat     * and frame max values after tuning has taken place.     * @throws IOException if an error is encountered     * either before, or during, protocol negotiation;     * sub-classes {@link ProtocolVersionMismatchException} and     * {@link PossibleAuthenticationFailureException} will be thrown in the     * corresponding circumstances. If an exception is thrown, connection     * resources allocated can all be garbage collected when the connection     * object is no longer referenced.     */    public void start()        throws IOException    {        this._running = true;        // Make sure that the first thing we do is to send the header,        // which should cause any socket errors to show up for us, rather        // than risking them pop out in the MainLoop        AMQChannel.SimpleBlockingRpcContinuation connStartBlocker =            new AMQChannel.SimpleBlockingRpcContinuation();        // We enqueue an RPC continuation here without sending an RPC        // request, since the protocol specifies that after sending        // the version negotiation header, the client (connection        // initiator) is to wait for a connection.start method to        // arrive.        _channel0.enqueueRpc(connStartBlocker);        try {            // The following two lines are akin to AMQChannel's            // transmit() method for this pseudo-RPC.            _frameHandler.setTimeout(HANDSHAKE_TIMEOUT);            _frameHandler.sendHeader();        } catch (IOException ioe) {            _frameHandler.close();            throw ioe;        }        // start the main loop going        new MainLoop("AMQP Connection " + getHostAddress() + ":" + getPort()).start();        // after this point clear-up of MainLoop is triggered by closing the frameHandler.        AMQP.Connection.Start connStart = null;        AMQP.Connection.Tune connTune = null;        try {            connStart =                (AMQP.Connection.Start) connStartBlocker.getReply().getMethod();            _serverProperties = Collections.unmodifiableMap(connStart.getServerProperties());            Version serverVersion =                new Version(connStart.getVersionMajor(),                            connStart.getVersionMinor());            if (!Version.checkVersion(clientVersion, serverVersion)) {                throw new ProtocolVersionMismatchException(clientVersion,                                                           serverVersion);            }            String[] mechanisms = connStart.getMechanisms().toString().split(" ");            SaslMechanism sm = this.saslConfig.getSaslMechanism(mechanisms);            if (sm == null) {                throw new IOException("No compatible authentication mechanism found - " +                        "server offered [" + connStart.getMechanisms() + "]");            }            LongString challenge = null;            LongString response = sm.handleChallenge(null, this.username, this.password);            do {                Method method = (challenge == null)                    ? new AMQP.Connection.StartOk.Builder()                                    .clientProperties(_clientProperties)                                    .mechanism(sm.getName())                                    .response(response)                          .build()                    : new AMQP.Connection.SecureOk.Builder().response(response).build();                try {                    Method serverResponse = _channel0.rpc(method).getMethod();                    if (serverResponse instanceof AMQP.Connection.Tune) {                        connTune = (AMQP.Connection.Tune) serverResponse;                    } else {                        challenge = ((AMQP.Connection.Secure) serverResponse).getChallenge();                        response = sm.handleChallenge(challenge, this.username, this.password);                    }                } catch (ShutdownSignalException e) {                    throw new PossibleAuthenticationFailureException(e);                }            } while (connTune == null);        } catch (ShutdownSignalException sse) {            _frameHandler.close();            throw AMQChannel.wrap(sse);        } catch(IOException ioe) {            _frameHandler.close();            throw ioe;        }        try {            int channelMax =                negotiatedMaxValue(this.requestedChannelMax,                                   connTune.getChannelMax());            _channelManager = new ChannelManager(this._workService, channelMax);            int frameMax =                negotiatedMaxValue(this.requestedFrameMax,                                   connTune.getFrameMax());            this._frameMax = frameMax;            int heartbeat =                negotiatedMaxValue(this.requestedHeartbeat,                                   connTune.getHeartbeat());            setHeartbeat(heartbeat);            _channel0.transmit(new AMQP.Connection.TuneOk.Builder()                                .channelMax(channelMax)                                .frameMax(frameMax)                                .heartbeat(heartbeat)                              .build());            _channel0.exnWrappingRpc(new AMQP.Connection.Open.Builder()                                      .virtualHost(_virtualHost)                                    .build());        } catch (IOException ioe) {            _heartbeatSender.shutdown();            _frameHandler.close();            throw ioe;        } catch (ShutdownSignalException sse) {            _heartbeatSender.shutdown();            _frameHandler.close();            throw AMQChannel.wrap(sse);        }        // We can now respond to errors having finished tailoring the connection        this._inConnectionNegotiation = false;        return;    }

转载：http://wubin850219.iteye.com/blog/1007984