Polish "Add config prop for Rabbit's max inbound message body size"

See gh-37603

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

@@ -26,6 +26,7 @@ import org.springframework.boot.autoconfigure.amqp.RabbitConnectionDetails.Addre
 import org.springframework.boot.context.properties.PropertyMapper;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.util.Assert;
+import org.springframework.util.unit.DataSize;
 
 /**
  * Configures {@link RabbitConnectionFactoryBean} with sensible defaults.
@@ -135,7 +136,8 @@ public class RabbitConnectionFactoryBeanConfigurer {
 		map.from(this.credentialsRefreshService).whenNonNull().to(factory::setCredentialsRefreshService);
 		map.from(this.rabbitProperties.getMaxInboundMessageBodySize())
 			.whenNonNull()
-			.to((mimbs) -> factory.setMaxInboundMessageBodySize(Math.toIntExact(mimbs.toBytes())));
+			.asInt(DataSize::toBytes)
+			.to(factory::setMaxInboundMessageBodySize);
 	}
 
 }

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

@@ -132,9 +132,9 @@ public class RabbitProperties {
 	private Duration channelRpcTimeout = Duration.ofMinutes(10);
 
 	/**
-	 * Maximum body size of inbound (received) messages in bytes.
+	 * Maximum size of the body of inbound (received) messages.
 	 */
-	private DataSize maxInboundMessageBodySize;
+	private DataSize maxInboundMessageBodySize = DataSize.ofMegabytes(64);
 
 	/**
 	 * Cache configuration.

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

@@ -150,9 +150,8 @@ class RabbitAutoConfigurationTests {
 			com.rabbitmq.client.ConnectionFactory rabbitConnectionFactory = getTargetConnectionFactory(context);
 			assertThat(rabbitConnectionFactory.getUsername()).isEqualTo(properties.getUsername());
 			assertThat(rabbitConnectionFactory.getPassword()).isEqualTo(properties.getPassword());
-			com.rabbitmq.client.ConnectionFactory defaultCf = new com.rabbitmq.client.ConnectionFactory();
-			assertThat(rabbitConnectionFactory).hasFieldOrPropertyWithValue("maxInboundMessageBodySize",
-					ReflectionTestUtils.getField(defaultCf, "maxInboundMessageBodySize"));
+			assertThat(rabbitConnectionFactory).extracting("maxInboundMessageBodySize")
+				.isEqualTo((int) properties.getMaxInboundMessageBodySize().toBytes());
 		});
 	}