RabbitMQ四种Exchange类型之Direct (Erlang)

Direct类型的Exchanges是处理路由键的，需要将一个队列绑定到交换机上，要求该消息与一个特定的路由键完全匹配。这是一个完整的匹配。如果一个队列绑定到该交换机上要求路由键为 “logs”，则只有路由键为“logs”的消息才被转发，不会转发路由键为"logs.error"，只会转发路由键为"logs"。 

如下图：

下面是代码实现！！！

消费者：

-module(mod_direct_receive).-behaviour(gen_server).-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).-export([start_link/1]).-include("common.hrl").-record(state, {routing_key = <<"">>}).start_link(RoutingKey) ->Server1 = lists:concat([?MODULE,erlang:binary_to_list(RoutingKey)]),Server2 = erlang:list_to_atom(Server1),gen_server:start_link({local,Server2}, ?MODULE, [RoutingKey], []).init([RoutingKey]) ->start(RoutingKey),    {ok, #state{routing_key=RoutingKey}}.handle_call(_Request, _From, State) ->    Reply = ok,    {reply, Reply, State}.handle_cast(_Msg, State) ->    {noreply, State}.handle_info({'basic.consume_ok',_}, State) ->{noreply, State};handle_info({#'basic.deliver'{},#amqp_msg{payload=Msg}}, State) ->io:format(" [routing_key = ~p] receive  messages is ~p~n",[State#state.routing_key,Msg]),{noreply, State};handle_info(Info, State) ->io:format("[routing_key = ~p] unknown messages is ~p~n", [State#state.routing_key,Info]),    {noreply, State}.terminate(_Reason, _State) ->    ok.code_change(_OldVsn, State, _Extra) ->    {ok, State}.start(RoutingKey) ->Params = #amqp_params_network{host=?HOST,username=?USER_NAME,password=?PASSWORD},case amqp_connection:start(Params) of{ok,ConnectionPid} ->{ok, Channel} = amqp_connection:open_channel(ConnectionPid),%%生成队列名称Queue = lists:concat([fanout_queue,now_time()]),QueueName = erlang:list_to_binary(Queue),%%声明队列amqp_channel:call(Channel, #'queue.declare'{queue = QueueName,auto_delete=true}),%%声明exchangeamqp_channel:call(Channel, #'exchange.declare'{ auto_delete =true,exchange = <<"direct">>, type = ?EXCHANGE_TYPE_DIRECT}),%%队列绑定到exchangeamqp_channel:call(Channel, #'queue.bind'{queue = QueueName, exchange = <<"direct">>,routing_key = RoutingKey}),io:format(" [routing_key = ~p] Waiting for messages......~n",[RoutingKey]),amqp_channel:subscribe(Channel, #'basic.consume'{queue = QueueName,no_ack = true}, self());{error,Resaon} ->io:format("[routing_key = ~p] connection rabbit error: ~p~n", [RoutingKey,Resaon]),Resaonend.now_time()->{A, B, _} = os:timestamp(),    A * 1000000 + B.

生产者：

-module(mod_direct_send).-export([send/2]).-include("common.hrl").send(Msg,RoutingKey) ->Params = #amqp_params_network{host=?HOST,username=?USER_NAME,password=?PASSWORD},case amqp_connection:start(Params) of{ok,ConnectionPid} ->{ok, Channel} = amqp_connection:open_channel(ConnectionPid),amqp_channel:cast(Channel,  #'basic.publish'{routing_key = RoutingKey,    exchange = <<"direct">>},  #amqp_msg{payload = Msg}),io:format("Sent '~p'~n",[Msg]),amqp_channel:close(Channel),amqp_connection:close(ConnectionPid);{error,Reason} ->Reasonend.

common头文件：

-include("amqp_client_internal.hrl").-define(USER_NAME , <<"test">>).-define(PASSWORD , <<"test">>).-define(HOST , "192.168.249.128").-define(PORT , 5672).%%exchanges type-define(EXCHANGE_TYPE_FANOUT, <<"fanout">> ).-define(EXCHANGE_TYPE_DIRECT, <<"direct">> ).

运行结果：

祝生活愉快！！！