Test that HTTP/1.1 still works when HTTP/2 is enabled

See gh-25856

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyReactiveWebServerFactory.java

@@ -26,7 +26,7 @@ import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.eclipse.jetty.http2.server.HTTP2ServerConnectionFactory;
+import org.eclipse.jetty.http2.server.HTTP2CServerConnectionFactory;
 import org.eclipse.jetty.server.AbstractConnector;
 import org.eclipse.jetty.server.ConnectionFactory;
 import org.eclipse.jetty.server.Handler;
@@ -199,10 +199,10 @@ public class JettyReactiveWebServerFactory extends AbstractReactiveWebServerFact
 		HttpConfiguration httpConfiguration = new HttpConfiguration();
 		httpConfiguration.setSendServerVersion(false);
 		List<ConnectionFactory> connectionFactories = new ArrayList<>();
-		if (getHttp2() != null && getHttp2().isEnabled()) {
-			connectionFactories.add(new HTTP2ServerConnectionFactory(httpConfiguration));
-		}
 		connectionFactories.add(new HttpConnectionFactory(httpConfiguration));
+		if (getHttp2() != null && getHttp2().isEnabled()) {
+			connectionFactories.add(new HTTP2CServerConnectionFactory(httpConfiguration));
+		}
 		JettyResourceFactory resourceFactory = getResourceFactory();
 		ServerConnector connector;
 		if (resourceFactory != null) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyServletWebServerFactory.java

@@ -34,7 +34,7 @@ import java.util.List;
 import java.util.Set;
 
 import org.eclipse.jetty.http.MimeTypes;
-import org.eclipse.jetty.http2.server.HTTP2ServerConnectionFactory;
+import org.eclipse.jetty.http2.server.HTTP2CServerConnectionFactory;
 import org.eclipse.jetty.server.AbstractConnector;
 import org.eclipse.jetty.server.ConnectionFactory;
 import org.eclipse.jetty.server.Connector;
@@ -180,10 +180,10 @@ public class JettyServletWebServerFactory extends AbstractServletWebServerFactor
 		HttpConfiguration httpConfiguration = new HttpConfiguration();
 		httpConfiguration.setSendServerVersion(false);
 		List<ConnectionFactory> connectionFactories = new ArrayList<>();
-		if (getHttp2() != null && getHttp2().isEnabled()) {
-			connectionFactories.add(new HTTP2ServerConnectionFactory(httpConfiguration));
-		}
 		connectionFactories.add(new HttpConnectionFactory(httpConfiguration));
+		if (getHttp2() != null && getHttp2().isEnabled()) {
+			connectionFactories.add(new HTTP2CServerConnectionFactory(httpConfiguration));
+		}
 		ServerConnector connector = new ServerConnector(server, this.acceptors, this.selectors,
 				connectionFactories.toArray(new ConnectionFactory[0]));
 		connector.setHost(address.getHostString());

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/server/AbstractReactiveWebServerFactoryTests.java

@@ -491,6 +491,21 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 		}
 	}
 
+	@Test
+	protected void whenHttp2IsEnabledAndSslIsDisabledThenHttp11CanStillBeUsed()
+			throws InterruptedException, ExecutionException, IOException {
+		AbstractReactiveWebServerFactory factory = getFactory();
+		Http2 http2 = new Http2();
+		http2.setEnabled(true);
+		factory.setHttp2(http2);
+		this.webServer = factory.getWebServer(new EchoHandler());
+		this.webServer.start();
+		Mono<String> result = getWebClient(this.webServer.getPort()).build().post().uri("/test")
+				.contentType(MediaType.TEXT_PLAIN).body(BodyInserters.fromValue("Hello World")).retrieve()
+				.bodyToMono(String.class);
+		assertThat(result.block(Duration.ofSeconds(30))).isEqualTo("Hello World");
+	}
+
 	protected WebClient prepareCompressionTest() {
 		Compression compression = new Compression();
 		compression.setEnabled(true);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java

@@ -1162,6 +1162,18 @@ public abstract class AbstractServletWebServerFactoryTests {
 		}
 	}
 
+	@Test
+	protected void whenHttp2IsEnabledAndSslIsDisabledThenHttp11CanStillBeUsed()
+			throws InterruptedException, ExecutionException, IOException, URISyntaxException {
+		AbstractServletWebServerFactory factory = getFactory();
+		Http2 http2 = new Http2();
+		http2.setEnabled(true);
+		factory.setHttp2(http2);
+		this.webServer = factory.getWebServer(exampleServletRegistration());
+		this.webServer.start();
+		assertThat(getResponse("http://localhost:" + this.webServer.getPort() + "/hello")).isEqualTo("Hello World");
+	}
+
 	protected Future<Object> initiateGetRequest(int port, String path) {
 		return initiateGetRequest(HttpClients.createMinimal(), port, path);
 	}