Spring Integration消息通道默认情况下将消息存储在内存中。 这是因为内存速度快，易于实现，并且不会增加网络成本。 但是，在某些情况下，这可能会引起问题，因为如果应用程序崩溃或服务器意外关闭，所有消息都将丢失。 对于这种情况，Spring Integration引入了JMS＆AMQP支持的消息通道，因此消息存储在JMS＆AMQP代理内而不是内存中。
高级消息队列协议（AMQP）是消息协议的开放标准。 它允许应用程序异步，可靠和安全地进行通信。 RabbitMQ是支持AMQP标准的开源消息代理。 RabbitMQ最重要的功能之一就是高可用性队列。
在本文中，通过创建两个消息传递节点和一个覆盖两个RabbitMQ服务器的RabbitMQ集群来说明Spring Integration的AMQP支持的点对点消息通道方法。 两个消息传递节点开始使用RabbitMQ集群处理Order消息。 如果第一消息节点和第一RabbitMQ服务器意外关闭，第二消息节点和第二RabbitMQ服务器将继续处理Order消息，因此可以通过使用高可用性AMQP支持的通道来防止潜在的消息丢失和服务中断问题。
还建议使用Spring Integration进行消息处理文章介绍一下Spring Integration的主要组件。
订单消息系统的Spring集成流程如下：
订单列表通过Order Gateway发送到Order Splitter的输入通道。 订单拆分器将订单列表拆分为订单消息，然后将其发送到“订单流程服务激活器”。 processChannel是点对点AMQP支持的消息通道。 它创建了RabbitMQ集群管理的ha.rabbit.channel队列，并将订单消息发送到ha.rabbit.channel Rabbit队列以实现高可用性。
让我们看一下示例订单消息传递实现。
二手技术：
- JDK 1.8.0_25
- Spring4.1.4
- Spring Integration 4.1.2
- RabbitMQ服务器3.4.2
- Maven 3.2.2
- Ubuntu 14.04
项目层次结构如下：
步骤1：依存关系
Spring和Spring Integration Framework的依赖关系如下：
<properties><spring.version>4.1.4.RELEASE</spring.version><spring.integration.version>4.1.2.RELEASE</spring.integration.version></properties><dependencies><!-- Spring 4 dependencies --><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>${spring.version}</version></dependency><!-- Spring Integration dependencies --><dependency><groupId>org.springframework.integration</groupId><artifactId>spring-integration-core</artifactId><version>${spring.integration.version}</version></dependency><dependency><groupId>org.springframework.integration</groupId><artifactId>spring-integration-amqp</artifactId><version>${spring.integration.version}</version><scope>compile</scope></dependency><dependencies>第2步：rabbitmq.config
第一RabbitMQ Server的配置文件（rabbitmq.config）如下。 它应该放在../rabbitmq_server-version/etc/rabbitmq/下
[{rabbit, [ {tcp_listeners, [5672]},{collect_statistics_interval, 10000},{heartbeat,30},{cluster_partition_handling, pause_minority},{cluster_nodes, {[ 'rabbit@master','rabbit2@master'],disc}} ] },{rabbitmq_management, [ {http_log_dir,"/tmp/rabbit-mgmt"},{listener, [{port, 15672}]} ] },{rabbitmq_management_agent, [ {force_fine_statistics, true} ] }
].第二个RabbitMQ服务器的rabbitmq.config文件：
[{rabbit, [ {tcp_listeners, [5673]},{collect_statistics_interval, 10000},{heartbeat,30},{cluster_partition_handling, pause_minority},{cluster_nodes, {[ 'rabbit@master','rabbit2@master'],disc}} ] },{rabbitmq_management, [ {http_log_dir,"/tmp/rabbit-mgmt"},{listener, [{port, 15673}]} ] },{rabbitmq_management_agent, [ {force_fine_statistics, true} ] }
].步骤3：集成上下文
Spring Integration Context的创建如下。 订单列表通过Order Gateway发送到Order Splitter的输入通道。 订单拆分器将订单列表拆分为订单消息，然后将其发送到“订单流程服务激活器”。 processChannel是点对点AMQP支持的消息通道。 它创建了一个由RabbitMQ集群管理的ha.rabbit.channel队列，并将定单消息发送到ha.rabbit.channel RabbitMQ队列以实现高可用性。
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:int="http://www.springframework.org/schema/integration"xmlns:int-amqp="http://www.springframework.org/schema/integration/amqp"xmlns:rabbit="http://www.springframework.org/schema/rabbit"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/integrationhttp://www.springframework.org/schema/integration/spring-integration.xsdhttp://www.springframework.org/schema/integration/amqp http://www.springframework.org/schema/integration/amqp/spring-integration-amqp.xsdhttp://www.springframework.org/schema/rabbit http://www.springframework.org/schema/rabbit/spring-rabbit.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"><!-- Configuration for Component Scan --><context:component-scan base-package="com.onlinetechvision" /><context:property-placeholder location="classpath*:rabbitmq.properties"/><int:channel id="inputChannel"/><int:gateway id="orderGateway" service-interface="com.onlinetechvision.integration.OrderGateway" default-request-channel="inputChannel" /><int-amqp:channel id="processChannel"connection-factory="connectionFactory" message-driven="true"queue-name="ha.rabbit.channel" /><!-- RabbitMQ Connection Factory --><rabbit:connection-factory id="connectionFactory"addresses="${rabbitmq.addresses}" username="${rabbitmq.username}"password="${rabbitmq.password}" /><int:splitter id="orderSplitter" input-channel="inputChannel" output-channel="processChannel" /><int:service-activator input-channel="processChannel" ref="orderProcessService" method="process" /></beans>第4步：rabbitmq.properties
rabbitmq.properties的创建如下。 如果第一个RabbitMQ服务器意外关闭，第二个RabbitMQ将继续侦听Order消息。
rabbitmq.addresses=localhost:5672,localhost:5673
rabbitmq.username=guest
rabbitmq.password=guest步骤5：订单模型
订购Bean模型订购消息。
import java.io.Serializable;public class Order implements Serializable {private static final long serialVersionUID = -2138235868650860555L;private int id;private String name;public Order(int id, String name) {this.id = id;this.name = name;}//Getter and Setter Methods...@Overridepublic String toString() {return "Order [id=" + id + ", name=" + name + "]";}}步骤6：OrderGateway
OrderGateway接口提供对订单消息系统的应用程序访问。 它的默认请求通道是inputChannel。
import java.util.List;import org.springframework.messaging.Message;import com.onlinetechvision.model.Order;public interface OrderGateway {/*** Processes Order Request** @param message SI Message covering Order payload.*/void processOrderRequest(Message<List<Order>> message);
}步骤7：OrderSplitter
OrderSplitter监听inputChannel并将传入的Order List分解为Order消息。 订单消息将发送到AMQP支持的processChannel。
import java.util.List;import org.springframework.messaging.Message;
import org.springframework.stereotype.Component;import com.onlinetechvision.model.Order;@Component("orderSplitter")
public class OrderSplitter {/*** Splits Order List to Order message(s)** @param message SI Message covering Order List payload.* @return order list*/public List<Order> splitOrderList(Message<List<Order>> message) {return message.getPayload();}
}步骤8：ProcessService
通用流程服务接口向消息系统公开流程服务功能。
import org.springframework.messaging.Message;public interface ProcessService<T> {/*** Processes incoming message(s)** @param message SI Message.*/void process(Message<T> message);}步骤9：OrderProcessService
Order Process Service Activator侦听AMQP支持的processChannel并记录传入的Order消息。 添加睡眠以填充ha.rabbit.channel RabbitMQ队列。
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.messaging.Message;
import org.springframework.stereotype.Component;import com.onlinetechvision.model.Order;@Component("orderProcessService")
public class OrderProcessService implements ProcessService<Order> {private final Logger logger = LoggerFactory.getLogger(OrderProcessService.class);private final static long SLEEP_DURATION = 1_000;@Overridepublic void process(Message<Order> message) {try {Thread.sleep(SLEEP_DURATION);} catch (InterruptedException e) {Thread.currentThread().interrupt();}logger.debug("Node 1 - Received Message : " + message.getPayload());}}步骤10：申请
应用程序类通过初始化应用程序上下文来运行应用程序，并将订单消息发送到消息传递系统。 仅第一个消息传递节点创建Order消息，而两个消息传递节点处理它们。 请找到第一个和第二个消息传递节点的应用程序类，如下所示：
第一消息节点的应用程序类：
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executors;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;import com.onlinetechvision.integration.OrderGateway;
import com.onlinetechvision.model.Order;public class Application {private final static int MESSAGE_LIMIT = 1_000;private final static int ORDER_LIST_SIZE = 10;private final static long SLEEP_DURATION = 50;private static OrderGateway orderGateway;/*** Starts the application** @param String[] args**/public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");orderGateway = context.getBean(OrderGateway.class);Executors.newSingleThreadExecutor().execute(new Runnable() {@Overridepublic void run() {try {int firstIndex = 0, lastIndex = ORDER_LIST_SIZE;while(lastIndex <= MESSAGE_LIMIT) {Message<List<Order>> message = MessageBuilder.withPayload(getOrderList(firstIndex, lastIndex)).build();orderGateway.processOrderRequest(message);firstIndex += ORDER_LIST_SIZE;lastIndex += ORDER_LIST_SIZE;Thread.sleep(SLEEP_DURATION);}} catch (InterruptedException e) {Thread.currentThread().interrupt();}}});}/*** Creates a sample order list and returns.** @return order list*/private static List<Order> getOrderList(final int firstIndex, final int lastIndex) {List<Order> orderList = new ArrayList<>(lastIndex);for(int i = firstIndex; i < lastIndex; i++) {orderList.add(new Order(i, "Sample_Order_" + i));}return orderList;}}第二个消息传递节点的应用程序类：
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Application {/*** Starts the application** @param String[] args**/public static void main(String[] args) {new ClassPathXmlApplicationContext("applicationContext.xml");}}步骤11：RabbitMQ群集Bash脚本
First RabbitMQ Server的示例bash脚本如下。 另外，请查看RabbitMQ Cluster文档以了解其他配置步骤。
#!/bin/bash
echo "*** First RabbitMQ Server is setting up ***"export RABBITMQ_HOSTNAME=rabbit@master
export RABBITMQ_NODE_PORT=5672
export RABBITMQ_NODENAME=rabbit@master
export RABBITMQ_SERVER_START_ARGS="-rabbitmq_management listener [{port,15672}]"/DEV_TOOLS/rabbitmq_server-3.4.2/sbin/rabbitmq-server &echo "*** Second RabbitMQ Server is set up succesfully. ***"sleep 5echo "*** First RabbitMQ Server' s status : ***"/DEV_TOOLS/rabbitmq_server-3.4.2/sbin/rabbitmqctl status第二个RabbitMQ Server的示例bash脚本如下：
#!/bin/bash
echo "*** Second RabbitMQ Server is setting up ***"export RABBITMQ_HOSTNAME=rabbit2@master
export RABBITMQ_NODE_PORT=5673
export RABBITMQ_NODENAME=rabbit2@master
export RABBITMQ_SERVER_START_ARGS="-rabbitmq_management listener [{port,15673}]"/DEV_TOOLS/rabbitmq_server-3.4.2_2/sbin/rabbitmq-server &echo "*** Second RabbitMQ Server is set up succesfully. ***"sleep 5echo "*** Second RabbitMQ Server' s status : ***"/DEV_TOOLS/rabbitmq_server-3.4.2_2/sbin/rabbitmqctl statussleep 5echo "*** Second RabbitMQ Server is being added to cluster... ***"/DEV_TOOLS/rabbitmq_server-3.4.2_2/sbin/rabbitmqctl -n rabbit2@master stop_app
/DEV_TOOLS/rabbitmq_server-3.4.2_2/sbin/rabbitmqctl -n rabbit2@master join_cluster rabbit@master
/DEV_TOOLS/rabbitmq_server-3.4.2_2/sbin/rabbitmqctl -n rabbit2@master start_app
/DEV_TOOLS/rabbitmq_server-3.4.2/sbin/rabbitmqctl -n rabbit@master set_policy ha-all "^ha\." '{"ha-mode":"all"}'echo "*** Second RabbitMQ Server is added to cluster successfully... ***"sleep 5echo "*** Second RabbitMQ Server' s cluster status : ***"/DEV_TOOLS/rabbitmq_server-3.4.2_2/sbin/rabbitmqctl cluster_status步骤12：建立并执行专案
订单消息的操作结果如下：
- 第一个RabbitMQ服务器启动。
- 第二台RabbitMQ服务器已启动并添加到集群中。
RabbitMQ群集概述如下：
- 设置第一台RabbitMQ Server的高可用性（HA）策略。
- 第一个消息传递节点已启动。 它创建订单消息和流程。
启动第一个消息传递节点后，Spring Integration上下文会自动创建一个ha.rabbit.channel RabbitMQ队列，如下所示：
- 第二个消息传递节点已启动。 它不会创建Order消息，因此只会处理。
- 订单列表开始处理。
在第一个和第二个消息节点连接到RabbitMQ集群之后，ha.rabbit.channel队列详细信息如下：
第一台RabbitMQ服务器上的ha.rabbit.channel队列：
第二台RabbitMQ服务器上的ha.rabbit.channel队列：
- 第一个消息节点关闭。
- 首先，RabbitMQ Server关闭，并离开集群。
- 第二消息节点和第二RabbitMQ服务器处理传入的Order消息以实现高可用性，因此不会中断服务。 第二个RabbitMQ Node的屏幕截图如下：
还将看到以下控制台输出日志：
第一个消息节点控制台：
...22:32:51.838 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 1 - Received Message : Order [id=260, name=Sample_Order_260] 22:32:52.842 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 1 - Received Message : Order [id=261, name=Sample_Order_261] 22:32:53.847 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 1 - Received Message : Order [id=263, name=Sample_Order_263] 22:32:54.852 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 1 - Received Message : Order [id=264, name=Sample_Order_264]在消息ID：264被传递到第一个消息节点之后，它和第一个RabbitMQ节点被关闭，第二个消息节点和第二个RabbitMQ节点按以下方式处理剩余的订单消息：
第二个消息节点控制台：
...22:32:54.211 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=262, name=Sample_Order_262] 22:32:56.214 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=265, name=Sample_Order_265] 22:32:58.219 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=266, name=Sample_Order_266] 22:33:00.223 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=267, name=Sample_Order_267] 22:33:02.229 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=268, name=Sample_Order_268] 22:33:04.234 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=269, name=Sample_Order_269] 22:33:06.239 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=270, name=Sample_Order_270] 22:33:08.241 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=271, name=Sample_Order_271] 22:33:10.247 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=272, name=Sample_Order_272] 22:33:12.252 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=273, name=Sample_Order_273] 22:33:14.255 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=274, name=Sample_Order_274] 22:33:16.258 [SimpleAsyncTaskExecutor-1] DEBUG c.o.p.s.OrderProcessService - Node 2 - Received Message : Order [id=275, name=Sample_Order_275]...
源代码
- 源代码在Github上可用
参考文献
企业整合模式
Spring集成参考手册
Spring Integration 4.1.2.RELEASE API Pro Spring整合 RabbitMQ服务器文档
翻译自: https://www.javacodegeeks.com/2015/01/high-available-amqp-backed-message-channels-via-spring-integration-and-rabbitmq.html
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