// Java code usage example//// The @around @CheckPoint (long x) aspect does a high level (distributed)// logging of the checkpoint// The @CheckPointParameter annotated method parameters are logged// as properties with the log@CheckPoint(10)public void annotatedCheckPointMethod(@CheckPointParameter String user) { // -> results in @Before checkpoint logging    ....code ...}// -> results in @After checkpoint logging

在C＃中使用代码（7，.NET MVC Core 2.1 +，Autofac，Caste Core动态代理）

// C# code usage example//// The [CheckPoint (long x)] dynamic proxy interceptor// aspect does a high level (distributed) logging of the checkpoint// The [CheckPointParameter] annotated method parameters are logged// as properties with the log[CheckPoint(10)]public void AnnotatedCheckPointMethod([CheckPointParameter] String user){// -> results in @Before checkpoint logging    ....code ...}// -> results in @After checkpoint logging

概念：基本原则

public void DistributedCheckPointMethod(String user){    SendCheckPoint("before", 10, user);    ...code...    SendCheckPoint("after", 10, user);}public void SendCheckPoint(String place, long id, String user){    List
    
      props = new List
     
      (){user};    rest.CheckPoint(place, id, props);}
     
    

2.使用二进制库

public void DistributedCheckPointMethod(String user){    libApi.SendCheckPoint("before", 10, user);    ...code...    libApi.SendCheckPoint("after", 10, user);}

3.复制粘贴代码

public void DistributedCheckPointMethod(String user){    List
    
      props = new List
     
      (){user};    rest.CheckPoint(place, id, props);    ...code...    rest.CheckPoint("after", 10, props);}
     
    

4.使用面向切面

@CheckPoint(10)...@FeatureFlag("Feature1")...

因此，API被定义为“一个带有可选参数的单词”。无论调用或实现是什么，都将隐藏在切面代码中。这样，实现和API可以很干净地分开，并且由于实现更改而使API发生更改的机会确实很小。别忘了，您的API调用最终可能会在每个服务的数百个地方，以及数十个或更多的服务中结束。而且，是的，如果为此使用一个切面，并且使用一个（简单但有缺陷的设计）调用分布式服务，则您仍然创建了“SPOF God”服务。但是，至少，您对此具有最少的API，并且在代码中调用的次数最少，因此，实现更改的影响通常要小得多。

[Log("SomeClass")]public class SomeClass{   ....methods go here, and all methods do logging...}

高级设计

    	
     		
      			
       
        org.springframework.cloud
       			
       
        spring-cloud-starter-parent
       			
       
        Hoxton.SR3
       			
       
        pom
       			
       
        import
       		
      	
     
    
    	
     
      org.springframework.boot
     	
     
      spring-boot-starter-aop
     	
     
      2.2.5
     
    
    	
     
      org.aspectj
     	
     
      aspectjrt
     	
     
      1.9.5
     
    
    	
     
      com.nickwongdev
     	
     
      aspectj-maven-plugin
     	
     
      1.12.6
     
    

优点CTW

@Target(ElementType.METHOD)@Retention(RetentionPolicy.RUNTIME)public @interface CheckPoint {    long value() default 0;}

接下来，定义@Before切面实现：

@Configurable@Aspect@Component@Scope(ConfigurableBeanFactory.SCOPE_SINGLETON)public class CheckPointAspect {	 /**     * Fires checkpoint with properties.     *     * @throws java.lang.Throwable     * @see unitests for examples     *     *     * @param joinPoint place of method annotated     * @param checkPointAnnotation the checkpoint     * @return proceeding object return value of method being annotated     */    @Before("@annotation(checkPointAnnotation)")    public void CheckPointAnnotation(            final JoinPoint joinPoint,            CheckPoint checkPointAnnotation) throws Throwable {        log.info("1. for checkPoint {} ", checkPointAnnotation.value());		...do check point send here...	}}

接下来，使用定义一个（测试）接口@CheckPoint。确保在接口方法上定义属性：

public interface CheckPointTest {	@CheckPoint(id=10) 	void doCheck();}

然后，实现测试类：

@Componentpublic class CheckPointTestImpl implements CheckPointTest {    @Override    public void doCheck() {		log.info("2. CheckPointTestImpl.doCheck");    }

CTW Java Aspect编译器

    	
     
      org.aspectj
     	
     
      aspectjrt
     	
     
      1.9.5
     
    
    	
     
      com.nickwongdev
     	
     
      aspectj-maven-plugin
     	
     
      1.12.6
     	
     		
      11		
      
       11
      		
      
       none
      		
      
       11
      		
      
       true
      		
      			
       				
       
        src/main/java
       				
       					
        
         nl/bebr/xdat/checkpoint/api/*.*
        				
       					
      	
     	
     		
      			
       				
        
         compile
        				
        
         test-compile
        			
       		
      	
     	
     		
      			
       
        org.aspectj
       			
       
        aspectjtools
       			
       
        1.9.5
       		
      	
     
    

注1：当您执行LTW Spring AOP时，切面类是由Spring Boot的容器加载和管理的，因此自动为您完成了布线。CTW没有这样的事情。Aspect编译器以及您的切面和Spring Boot IOC在开箱即用时效果不佳。您必须手动连接各个切面。否则，您@Autowiring将失败。

..../** * This is plumbing code to connect the CTW aspect to the Spring Boot IOC container  * of your app context. * Otherwise, the CheckPointAspect is factored by the aspectj compiler,  * and then, your autowiring fails, resulting in nulls for all your @Autowired props.  * So, you need to include this method in all your CTW aspects. * I suppose the aspectjrt checks if this method is available, * and then uses it to factor your objects via Spring Boot?  * @return CheckPointAspect */public static CheckPointAspect aspectOf() {	return  SpringApplicationContextHolder.getApplicationContext().                                           getBean(CheckPointAspect.class);}...//Helper class for your CTW/Spring Boot container wiring stuff	@Componentpublic class SpringApplicationContextHolder implements ApplicationContextAware {    private static ApplicationContext applicationContext = null;    public static ApplicationContext getApplicationContext() {        return applicationContext;    }    @Override    public void setApplicationContext(ApplicationContext applicationContext)            throws BeansException {       this.applicationContext = applicationContext;    }}

注意：Lombok是我最喜欢的组件之一。它节省了很多样板代码，并且@Builder模式很完美。但是，Maven Aspectj编译器不能与Lombok配合使用。由于Aspectj在Lombok之前运行，因此您还没有构建器和getter/setter，并且Aspectj编译器不再理解您的代码。我只能通过排除DTO软件包来使其工作：

    	
     		
     
      src/main/java
     		
     			
      
       nl/bebr/xdat/checkpoint/api/*.*
      		
     	
    

Java Aspect总结

Autofac : 5.1.0Autofac.Extras.DynamicProxy : 5.0.0Castle.Core: 4.4.0FakeItEasy: 6.0.0

这个c#中的DynamicProxy是如何工作的？

public interface AOPTest{	//	// Castle DynamicProxy interceptor	//	[CheckPoint(Id = 10)]	void DoSomething();	//	// FilterAttribute	//	[CheckPointActionAtrribute(Id = 10)]	void DoAction();}

然后，实现接口：

public class AOPTestImpl : AOPTest{    // -> invocation point    // @Before is done in the interceptor below, 1. and 2.    public void DoSomething()    {        //        // invocation.Proceed() : Method block code goes below here        //        Debug.Print("3. DoSomething\n");        //        // 4. @After invocation is done in the interceptor below,        // after the invocation.Proceed(); call        //    }    public void DoAction()    {    }}

然后，定义拦截器。

public class CheckPointInterceptor : Castle.DynamicProxy.IInterceptor	{		//		// As we use PropertiesAutowired() with AutoFac,         // this object is set by the IOC container		//		public CheckPointClient checkPointClient { get; set; }				public void Intercept(Castle.DynamicProxy.IInvocation invocation)		{			Debug.Print($"1. @Before Method called {invocation.Method.Name}");			var methodAttributes = invocation.Method.GetCustomAttributes(false);			CheckPointAttribute theCheckPoint =(CheckPointAttribute)methodAttributes.Where                (a => a.GetType() == typeof(CheckPointAttribute)).SingleOrDefault();			if (theCheckPoint == null)			{				//@before intercepting code goes here				checkPointClient.CheckPoint(theCheckPoint.Id);				Debug.Print($"2. CheckPointAttribute on method found with cp id =                                {theCheckPoint.Id}\n");			}			//			// This is the actual "implementation method code block".			// @Before code goes above this call			//			invocation.Proceed();			//			// Any @After method block code goes below here			//			Debug.Print($"4. @After method: {invocation.Method.Name}");		}	}

接下来，使用AutoFac注册对象：

var builder = new ContainerBuilder();...builder.RegisterType
    
     ()            .As
     
      ()            .EnableInterfaceInterceptors()            .InterceptedBy(typeof(CheckPointInterceptor))            .PropertiesAutowired()            .PreserveExistingDefaults();...var container = builder.Build();...
     
    

最后，让我们测试并使用代码：

using (var scope = container.BeginLifetimeScope()){    //    // Create the registered AOPTest object, with the interceptor in between    //    AOPTest aOPTest = scope.Resolve
    
     ();    //    // Call the method, with the [CheckPoint(Id = 10)] on it    //    aOPTest.DoSomething();}
    

应导致：

[HttpGet("index")][CheckPoint(Id = 10)]public ActionResult Index(){	Debug.Print("3. Index\n");	....}

乍一看，这似乎可行。您必须将AutoFac连接到Microsoft Extensions DependencyInjection。

public void Intercept(Castle.DynamicProxy.IInvocation invocation) {..}

由于ActionResult的异步行为，现在突然被调用了多次，并且没有棘手的、复杂的、繁琐的代码，您将无法使这项工作正常进行。

public class CheckPointActionAtrribute : Microsoft.AspNetCore.Mvc.Filters.ActionFilterAttribute{	//	// Your custom checkpoint Id for this CheckPoint attribute	//	public long Id { get; set; }	//	// @Before	//	public override void OnActionExecuting         (Microsoft.AspNetCore.Mvc.Filters.ActionExecutingContext context)	{		ControllerActionDescriptor actionDescriptor =                    (ControllerActionDescriptor)context.ActionDescriptor;		Debug.Print($"1. @Before Method called            {actionDescriptor.ControllerName}.{actionDescriptor.ActionName}");		var controllerName = actionDescriptor.ControllerName;		var actionName = actionDescriptor.ActionName;		var parameters = actionDescriptor.Parameters;		var fullName = actionDescriptor.DisplayName;		//		// CheckPointActionAtrribute are not factored by the IOC		// 		CheckPointClient checkPointClient = BootStapper.Resolve
    
     ();		checkPointClient.CheckPoint(Id);	}		//	// @After	//	public override void OnActionExecuted(ActionExecutedContext context)	{		ControllerActionDescriptor actionDescriptor =                     (ControllerActionDescriptor)context.ActionDescriptor;		Debug.Print($"3. @After method:                 {actionDescriptor.ControllerName}.{actionDescriptor.ActionName}");	}}
    

最后步骤2，应用特性：

[HttpGet("index")][CheckPointActionAtrribute(Id = 10)]public ActionResult Index(){	Debug.Print("3. CheckPointController.Index\n");	....}

结果应该是这样的：

builder.RegisterType<..>()               .As<..>()               .EnableInterfaceInterceptors()

并添加.EnableClassInterceptors()。

public class ExchangeDefinition {    public static final String CHECKPOINT_EXCHANGE = "ricta.checkpoint.exchange";    public static final String KEY_CHECKPOINT_REQUEST = "checkpoint.check.request";}	@Configurationpublic class CheckPointExchangeConfig implements RabbitListenerConfigurer {    @Autowired    ConnectionFactory connectionFactory;    @Bean    public Exchange checkPointEventExchange() {        return new TopicExchange(CHECKPOINT_EXCHANGE);    }    @Override    public void configureRabbitListeners(final RabbitListenerEndpointRegistrar registrar) {        registrar.setMessageHandlerMethodFactory(messageHandlerMethodFactory());    }    @Bean    public Jackson2JsonMessageConverter producerJackson2MessageConverter() {        return new Jackson2JsonMessageConverter();    }    @Bean    public MappingJackson2MessageConverter consumerJackson2MessageConverter() {        return new MappingJackson2MessageConverter();    }    @Bean    public DefaultMessageHandlerMethodFactory messageHandlerMethodFactory() {        DefaultMessageHandlerMethodFactory factory = new DefaultMessageHandlerMethodFactory();        factory.setMessageConverter(consumerJackson2MessageConverter());        return factory;    }    @Bean    public RabbitTemplate rabbitTemplate(final ConnectionFactory connectionFactory) {        final RabbitTemplate rabbitTemplate = new RabbitTemplate(connectionFactory);        rabbitTemplate.setMessageConverter(producerJackson2MessageConverter());        return rabbitTemplate;    }}

然后，您需要声明并绑定您的队列。同样，在一个单独的类中：

public class QueueDefinition {    public static final String QUEUE_CHECKPOINT_REQUEST = KEY_CHECKPOINT_REQUEST;}@Configurationpublic class CheckPointQueueConfig implements RabbitListenerConfigurer {	    @Bean    public Queue queueCheckpointRequest() {        return new Queue(QueueDefinition.QUEUE_CHECKPOINT_REQUEST);    }    @Bean    public Binding checkPointRequestBinding     (Queue queueCheckpointRequest, Exchange checkPointEventExchange) {        return BindingBuilder                .bind(queueCheckpointRequest)                .to(checkPointEventExchange)                .with(KEY_CHECKPOINT_REQUEST)                .noargs();    }    @Autowired    DefaultMessageHandlerMethodFactory messageHandlerMethodFactory;    @Override    public void configureRabbitListeners(final RabbitListenerEndpointRegistrar registrar) {        registrar.setMessageHandlerMethodFactory(messageHandlerMethodFactory);    }}

接下来，为了发送消息，我们使用RabbitTemplate：

{	...	@Autowired	private RabbitTemplate rabbitTemplate;	@Override	public void sendToExhange(Message message) {		rabbitTemplate.send(ExchangeDefinition.CHECKPOINT_EXCHANGE,                             ExchangeDefinition.KEY_CHECKPOINT_REQUEST, message);	}	...}

再次注意：您发送到Exchange，并从队列中接收/收听。

{	....	@RabbitListener(queues = QUEUE_CHECKPOINT_REQUEST)	public void handleCheckPointMessage(Message message)			throws IOException {		....	}	....}

因此，到此结束了用Java发送和接收RabbitMQ消息。

{...	/**	 * Props to stop listeners by startup in yml do not work. 	 * rabbitmq.listener.auto-startup: false	 * rabbitmq.listener.simple.auto-startup: false	 * So use this factory construction	 * @param connectionFactory	 * @return 	 */	@Bean	public SimpleRabbitListenerContainerFactory rabbitListenerContainerFactory        (ConnectionFactory connectionFactory) {		SimpleRabbitListenerContainerFactory factory =             new SimpleRabbitListenerContainerFactory();		factory.setConnectionFactory(connectionFactory);		//		//autoStartup = false, prevents handling messages immediately.         // You need to start each listener itself. 		// Use BaseResponseMediaDTOQueueListener.startRabbitListener/stopRabbitListener		//		factory.setAutoStartup(false); 		factory.setMessageConverter(new Jackson2JsonMessageConverter());		return factory;	}	...	@Autowired	private RabbitListenerEndpointRegistry rabbitListenerEndpointRegistry;		public boolean startRabbitListener(String rabbitListenerId) {		MessageListenerContainer listener =             rabbitListenerEndpointRegistry.getListenerContainer(rabbitListenerId);		if (listener != null) {			listener.start();			return true;		} else {			 return false;		}	}	public boolean stopRabbitListener(String rabbitListenerId) {		MessageListenerContainer listener =               rabbitListenerEndpointRegistry.getListenerContainer(rabbitListenerId);		if (listener != null) {			listener.stop();			return true;		} else {			 return false;		}	}}

DotNET 消息

using (var connection = ConnectionFactory.CreateConnection())using (var channel = connection.CreateModel()){	//	// At one place in time, you have to declare the exchange and topic queues, and bind them	//	var queue = channel.QueueDeclare(queue: "checkpoint.check.request",						 durable: true,						 exclusive: false,						 autoDelete: false,						 arguments: null);	channel.ExchangeDeclare("ricta.checkpoint.exchange",							ExchangeType.Topic);	channel.QueueBind(queue.QueueName,		"ricta.checkpoint.exchange",		"checkpoint.check.*"		);			string message = Id.ToString();	var body = Encoding.UTF8.GetBytes(message);	IBasicProperties props = channel.CreateBasicProperties();	props.AppId = "DEMO-APP";	DateTime now = DateTime.UtcNow;	long unixTime = ((DateTimeOffset)now).ToUnixTimeSeconds();	props.Timestamp = new AmqpTimestamp(unixTime);	props.Type = "application/json";	props.Headers = new Dictionary
    
     	{		{ "__TypeId__", "java.lang.String" }	};	channel.BasicPublish(exchange: "ricta.checkpoint.exchange",					routingKey: "checkpoint.check.request",					basicProperties: props,					body: body);	Console.WriteLine(" [x] Sent {0}", message);}
    

通过RabbitMQ.Client以下方式接收队列消息：

{	var factory = new ConnectionFactory { HostName = "localhost" };	//	// create connection  	//	_connection = factory.CreateConnection();	//	// create channel  	//	_channel = _connection.CreateModel();	_channel.ExchangeDeclare("ricta.checkpoint.exchange", ExchangeType.Topic, true);	_channel.QueueDeclare("ricta.check.request", true, false, false, null);	_channel.QueueBind("ricta.check.request", "ricta.checkpoint.exchange",                        "checkpoint.check.*", null);	_channel.BasicQos(0, 1, false);	//	// Create Consumer of messages	//	var consumer = new EventingBasicConsumer(_channel);	consumer.Received += (ch, ea) =>	{		//		// handle the received message 		//		HandleMessage(ea);		_channel.BasicAck(ea.DeliveryTag, false);	};	...	private void HandleMessage(BasicDeliverEventArgs args)	{		//		// received message, app id and time		//		var content = System.Text.Encoding.UTF8.GetString(args.Body);		var appId = args.BasicProperties.AppId;		var checkTime = System.DateTimeOffset.FromUnixTimeMilliseconds                        (args.BasicProperties.Timestamp.UnixTime).ToLocalTime().DateTime;		....	}}

至此，以C＃发送和接收RabbitMQ消息结束了。