Allow maximum HTTP header size to be configured when using Jetty 8

Closes gh-6190

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -1005,13 +1005,18 @@ public class ServerProperties
 				public void customize(Server server) {
 					for (org.eclipse.jetty.server.Connector connector : server
 							.getConnectors()) {
-						for (ConnectionFactory connectionFactory : connector
+						try {
-								.getConnectionFactories()) {
+							for (ConnectionFactory connectionFactory : connector
-							if (connectionFactory instanceof HttpConfiguration.ConnectionFactory) {
+									.getConnectionFactories()) {
-								customize(
+								if (connectionFactory instanceof HttpConfiguration.ConnectionFactory) {
-										(HttpConfiguration.ConnectionFactory) connectionFactory);
+									customize(
+											(HttpConfiguration.ConnectionFactory) connectionFactory);
+								}
 							}
 						}
+						catch (NoSuchMethodError ex) {
+							customizeOnJetty8(connector, maxHttpHeaderSize);
+						}
 					}
 
 				}
@@ -1022,6 +1027,20 @@ public class ServerProperties
 					configuration.setResponseHeaderSize(maxHttpHeaderSize);
 				}
 
+				private void customizeOnJetty8(
+						org.eclipse.jetty.server.Connector connector,
+						int maxHttpHeaderSize) {
+					try {
+						connector.getClass().getMethod("setRequestHeaderSize", int.class)
+								.invoke(connector, maxHttpHeaderSize);
+						connector.getClass().getMethod("setResponseHeaderSize", int.class)
+								.invoke(connector, maxHttpHeaderSize);
+					}
+					catch (Exception ex) {
+						throw new RuntimeException(ex);
+					}
+				}
+
 			});
 		}
 

spring-boot-samples/spring-boot-sample-jetty8/src/main/resources/application.properties

@@ -1,2 +1,3 @@
 server.compression.enabled: true
 server.compression.min-response-size: 1
+server.max-http-header-size: 4096