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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exchange amqp_channel:call(Channel, #'exchange.declare'{ auto_delete =true,exchange = <<"direct">>, type = ?EXCHANGE_TYPE_DIRECT}), %%队列绑定到exchange amqp_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]), Resaon end. 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} ->Reason end.
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:
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