Merge pull request #34050 from dangzhicairang

* pr/34050:
  Polish "Add RabbitTemplateCustomizer"
  Add RabbitTemplateCustomizer

Closes gh-34050

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/amqp/RabbitAutoConfiguration.java

@@ -154,9 +154,11 @@ public class RabbitAutoConfiguration {
 		@Bean
 		@ConditionalOnSingleCandidate(ConnectionFactory.class)
 		@ConditionalOnMissingBean(RabbitOperations.class)
-		public RabbitTemplate rabbitTemplate(RabbitTemplateConfigurer configurer, ConnectionFactory connectionFactory) {
+		public RabbitTemplate rabbitTemplate(RabbitTemplateConfigurer configurer, ConnectionFactory connectionFactory,
+				ObjectProvider<RabbitTemplateCustomizer> customizers) {
 			RabbitTemplate template = new RabbitTemplate();
 			configurer.configure(template, connectionFactory);
+			customizers.orderedStream().forEach((customizer) -> customizer.customize(template));
 			return template;
 		}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/amqp/RabbitTemplateCustomizer.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2012-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.autoconfigure.amqp;
+
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+
+/**
+ * Callback interface that can be used to customize a {@link RabbitTemplate}.
+ *
+ * @author dang zhicairang
+ * @since 3.1.0
+ */
+@FunctionalInterface
+public interface RabbitTemplateCustomizer {
+
+	/**
+	 * Callback to customize a {@link RabbitTemplate} instance.
+	 * @param rabbitTemplate the rabbitTemplate to customize
+	 */
+	void customize(RabbitTemplate rabbitTemplate);
+
+}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/amqp/RabbitAutoConfigurationTests.java

@@ -385,6 +385,22 @@ class RabbitAutoConfigurationTests {
 			});
 	}
 
+	@Test
+	void whenMultipleRabbitTemplateCustomizersAreDefinedThenTheyAreCalledInOrder() {
+		this.contextRunner.withUserConfiguration(MultipleRabbitTemplateCustomizersConfiguration.class)
+			.run((context) -> {
+				RabbitTemplateCustomizer firstCustomizer = context.getBean("firstCustomizer",
+						RabbitTemplateCustomizer.class);
+				RabbitTemplateCustomizer secondCustomizer = context.getBean("secondCustomizer",
+						RabbitTemplateCustomizer.class);
+				InOrder inOrder = inOrder(firstCustomizer, secondCustomizer);
+				RabbitTemplate template = context.getBean(RabbitTemplate.class);
+				then(firstCustomizer).should(inOrder).customize(template);
+				then(secondCustomizer).should(inOrder).customize(template);
+				inOrder.verifyNoMoreInteractions();
+			});
+	}
+
 	@Test
 	void testConnectionFactoryBackOff() {
 		this.contextRunner.withUserConfiguration(TestConfiguration2.class).run((context) -> {
@@ -992,6 +1008,23 @@ class RabbitAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class MultipleRabbitTemplateCustomizersConfiguration {
+
+		@Bean
+		@Order(Ordered.LOWEST_PRECEDENCE)
+		RabbitTemplateCustomizer secondCustomizer() {
+			return mock(RabbitTemplateCustomizer.class);
+		}
+
+		@Bean
+		@Order(0)
+		RabbitTemplateCustomizer firstCustomizer() {
+			return mock(RabbitTemplateCustomizer.class);
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class ConnectionNameStrategyConfiguration {
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/messaging/amqp.adoc

@@ -41,6 +41,8 @@ To configure lower-level details of the RabbitMQ `ConnectionFactory` that is use
 
 If a `ConnectionNameStrategy` bean exists in the context, it will be automatically used to name connections created by the auto-configured `CachingConnectionFactory`.
 
+To make an application-wide, additive customization to the `RabbitTemplate`, use a `RabbitTemplateCustomizer` bean.
+
 TIP: See https://spring.io/blog/2010/06/14/understanding-amqp-the-protocol-used-by-rabbitmq/[Understanding AMQP, the protocol used by RabbitMQ] for more details.