Polish 'Allow multiple hosts to be set in MongoProperties'

See gh-32125

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mongo/MongoProperties.java

@@ -61,6 +61,13 @@ public class MongoProperties {
 	 */
 	private Integer port = null;
 
+	/**
+	 * Additional server hosts. Cannot be set with URI or if 'host' is not specified.
+	 * Additional hosts will use the default mongo port of 27017, if you want to use a
+	 * different port you can use the "host:port" syntax.
+	 */
+	private List<String> additionalHosts;
+
 	/**
 	 * Mongo database URI. Overrides host, port, username, password, and database.
 	 */
@@ -108,11 +115,6 @@ public class MongoProperties {
 	 */
 	private Boolean autoIndexCreation;
 
-	/**
-	 * List of additional hosts to connect with different hosts in a replica set.
-	 */
-	private List<String> additionalHosts;
-
 	public String getHost() {
 		return this.host;
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/mongo/MongoPropertiesClientSettingsBuilderCustomizer.java

@@ -25,6 +25,7 @@ import com.mongodb.MongoCredential;
 import com.mongodb.ServerAddress;
 
 import org.springframework.core.Ordered;
+import org.springframework.util.CollectionUtils;
 
 /**
  * A {@link MongoClientSettingsBuilderCustomizer} that applies properties from a
@@ -64,22 +65,17 @@ public class MongoPropertiesClientSettingsBuilderCustomizer implements MongoClie
 		if (this.properties.getHost() != null || this.properties.getPort() != null) {
 			String host = getOrDefault(this.properties.getHost(), "localhost");
 			int port = getOrDefault(this.properties.getPort(), MongoProperties.DEFAULT_PORT);
-			ServerAddress serverAddress = new ServerAddress(host, port);
-			List<ServerAddress> serverAddressList = new ArrayList<>(List.of(serverAddress));
-			applyAdditionalHosts(serverAddressList);
-			settings.applyToClusterSettings((cluster) -> cluster.hosts(serverAddressList));
+			List<ServerAddress> serverAddresses = new ArrayList<>();
+			serverAddresses.add(new ServerAddress(host, port));
+			if (!CollectionUtils.isEmpty(this.properties.getAdditionalHosts())) {
+				this.properties.getAdditionalHosts().stream().map(ServerAddress::new).forEach(serverAddresses::add);
+			}
+			settings.applyToClusterSettings((cluster) -> cluster.hosts(serverAddresses));
 			return;
 		}
 		settings.applyConnectionString(new ConnectionString(MongoProperties.DEFAULT_URI));
 	}
 
-	private void applyAdditionalHosts(List<ServerAddress> serverAddressList) {
-		if (this.properties.getAdditionalHosts() != null && !this.properties.getAdditionalHosts().isEmpty()) {
-			this.properties.getAdditionalHosts()
-					.forEach((additionalHost) -> serverAddressList.add(new ServerAddress(additionalHost)));
-		}
-	}
-
 	private void applyCredentials(MongoClientSettings.Builder builder) {
 		if (this.properties.getUri() == null && this.properties.getUsername() != null
 				&& this.properties.getPassword() != null) {

spring-boot-project/spring-boot-docs/src/docs/asciidoc/data/nosql.adoc

@@ -80,7 +80,7 @@ You can set the configprop:spring.data.mongodb.uri[] property to change the URL
 	spring:
 	  data:
 	    mongodb:
-	      uri: "mongodb://user:secret@mongo1.example.com:12345,mongo2.example.com:23456/test"
+	      uri: "mongodb://user:secret@mongoserver1.example.com:27017,mongoserver2.example.com:23456/test"
 ----
 
 Alternatively, you can specify connection details using discrete properties.
@@ -91,16 +91,24 @@ For example, you might declare the following settings in your `application.prope
 	spring:
 	  data:
 	    mongodb:
-	      host: "mongoserver.example.com"
+	      host: "mongoserver1.example.com"
 	      port: 27017
+	      additional-hosts:
+	      - "mongoserver2.example.com:23456"
 	      database: "test"
 	      username: "user"
 	      password: "secret"
 ----
 
-TIP: If `spring.data.mongodb.port` is not specified, the default of `27017` is used.
+[TIP]
+====
+If `spring.data.mongodb.port` is not specified, the default of `27017` is used.
 You could delete this line from the example shown earlier.
 
+You can also specify the port as part of the host address by using the `host:port` syntax.
+This format should be used if you need to change the port of an `additional-hosts` entry.
+====
+
 TIP: If you do not use Spring Data MongoDB, you can inject a `MongoClient` bean instead of using `MongoDatabaseFactory`.
 If you want to take complete control of establishing the MongoDB connection, you can also declare your own `MongoDatabaseFactory` or `MongoClient` bean.