Early support for Jetty 12 (developed against 12.0.0.alpha2)

Reflective getHeaders calls to be revisited; see GitHub issue #8938 in Jetty project.
HttpOutput optimization commented out still in order to avoid alpha build dependency.

See gh-29575

spring-web/spring-web.gradle

@@ -37,6 +37,12 @@ dependencies {
 	optional("org.eclipse.jetty:jetty-servlet") {
 		exclude group: "jakarta.servlet", module: "jakarta.servlet-api"
 	}
+	/* Jetty 12: see org.springframework.http.server.reactive.JettyHttpHandlerAdapter
+	optional("org.eclipse.jetty.ee10:jetty-ee10-servlet:12.0.0.alpha2") {
+		exclude group: "jakarta.servlet", module: "jakarta.servlet-api"
+		exclude group: "org.eclipse.jetty", module: "jetty-session"
+	}
+	*/
 	optional("org.eclipse.jetty:jetty-reactive-httpclient")
 	optional('org.apache.httpcomponents.client5:httpclient5')
 	optional('org.apache.httpcomponents.core5:httpcore5-reactive')

spring-web/src/main/java/org/springframework/http/client/reactive/JettyHeadersAdapter.java

@@ -18,7 +18,6 @@ package org.springframework.http.client.reactive;
 
 import java.util.AbstractSet;
 import java.util.Collection;
-import java.util.Enumeration;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -186,7 +185,6 @@ class JettyHeadersAdapter implements MultiValueMap<String, String> {
 			public Iterator<Entry<String, List<String>>> iterator() {
 				return new EntryIterator();
 			}
-
 			@Override
 			public int size() {
 				return headers.size();
@@ -203,16 +201,16 @@ class JettyHeadersAdapter implements MultiValueMap<String, String> {
 
 	private class EntryIterator implements Iterator<Entry<String, List<String>>> {
 
-		private final Enumeration<String> names = headers.getFieldNames();
+		private final Iterator<String> names = headers.getFieldNamesCollection().iterator();
 
 		@Override
 		public boolean hasNext() {
-			return this.names.hasMoreElements();
+			return this.names.hasNext();
 		}
 
 		@Override
 		public Entry<String, List<String>> next() {
-			return new HeaderEntry(this.names.nextElement());
+			return new HeaderEntry(this.names.next());
 		}
 	}
 

spring-web/src/main/java/org/springframework/http/server/reactive/JettyHeadersAdapter.java

@@ -18,7 +18,6 @@ package org.springframework.http.server.reactive;
 
 import java.util.AbstractSet;
 import java.util.Collection;
-import java.util.Enumeration;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -46,8 +45,8 @@ class JettyHeadersAdapter implements MultiValueMap<String, String> {
 	private final HttpFields.Mutable headers;
 
 
-	JettyHeadersAdapter(HttpFields.Mutable headers) {
+	JettyHeadersAdapter(HttpFields headers) {
-		this.headers = headers;
+		this.headers = (headers instanceof HttpFields.Mutable mutable ? mutable : HttpFields.build(headers));
 	}
 
 
@@ -170,7 +169,6 @@ class JettyHeadersAdapter implements MultiValueMap<String, String> {
 			public Iterator<Entry<String, List<String>>> iterator() {
 				return new EntryIterator();
 			}
-
 			@Override
 			public int size() {
 				return headers.size();
@@ -187,16 +185,16 @@ class JettyHeadersAdapter implements MultiValueMap<String, String> {
 
 	private class EntryIterator implements Iterator<Entry<String, List<String>>> {
 
-		private final Enumeration<String> names = headers.getFieldNames();
+		private final Iterator<String> names = headers.getFieldNamesCollection().iterator();
 
 		@Override
 		public boolean hasNext() {
-			return this.names.hasMoreElements();
+			return this.names.hasNext();
 		}
 
 		@Override
 		public Entry<String, List<String>> next() {
-			return new HeaderEntry(this.names.nextElement());
+			return new HeaderEntry(this.names.next());
 		}
 	}
 

spring-web/src/main/java/org/springframework/http/server/reactive/JettyHttpHandlerAdapter.java

@@ -17,12 +17,13 @@
 package org.springframework.http.server.reactive;
 
 import java.io.IOException;
+import java.io.OutputStream;
+import java.lang.reflect.Method;
 import java.net.URISyntaxException;
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 
 import jakarta.servlet.AsyncContext;
-import jakarta.servlet.ServletResponse;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletRequestWrapper;
 import jakarta.servlet.http.HttpServletResponse;
@@ -36,8 +37,11 @@ import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.MultiValueMap;
+import org.springframework.util.ReflectionUtils;
 
 /**
  * {@link ServletHttpHandlerAdapter} extension that uses Jetty APIs for writing
@@ -50,6 +54,23 @@ import org.springframework.util.MultiValueMap;
  */
 public class JettyHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
+	private static final boolean jetty11Present = ClassUtils.isPresent(
+			"org.eclipse.jetty.server.HttpOutput", JettyHttpHandlerAdapter.class.getClassLoader());
+
+	/* Jetty 12: see spring-web.gradle
+	private static final boolean jetty12Present = ClassUtils.isPresent(
+			"org.eclipse.jetty.ee10.servlet.HttpOutput", JettyHttpHandlerAdapter.class.getClassLoader());
+	*/
+
+	@Nullable
+	private static final Method getRequestHeadersMethod =
+			ClassUtils.getMethodIfAvailable(Request.class, "getHeaders");
+
+	@Nullable
+	private static final Method getResponseHeadersMethod =
+			ClassUtils.getMethodIfAvailable(Response.class, "getHeaders");
+
+
 	public JettyHttpHandlerAdapter(HttpHandler httpHandler) {
 		super(httpHandler);
 	}
@@ -84,7 +105,13 @@ public class JettyHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
 		private static MultiValueMap<String, String> createHeaders(HttpServletRequest servletRequest) {
 			Request request = getRequest(servletRequest);
-			HttpFields.Mutable fields = HttpFields.build(request.getHttpFields());
+			HttpFields fields;
+			if (getRequestHeadersMethod != null) {
+				fields = (HttpFields) ReflectionUtils.invokeMethod(getRequestHeadersMethod, request);
+			}
+			else {
+				fields = request.getHttpFields();
+			}
 			return new JettyHeadersAdapter(fields);
 		}
 
@@ -115,7 +142,13 @@ public class JettyHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
 		private static HttpHeaders createHeaders(HttpServletResponse servletResponse) {
 			Response response = getResponse(servletResponse);
-			HttpFields.Mutable fields = response.getHttpFields();
+			HttpFields fields;
+			if (getResponseHeadersMethod != null) {
+				fields = (HttpFields) ReflectionUtils.invokeMethod(getResponseHeadersMethod, response);
+			}
+			else {
+				fields = response.getHttpFields();
+			}
 			return new HttpHeaders(new JettyHeadersAdapter(fields));
 		}
 
@@ -135,16 +168,32 @@ public class JettyHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
 		@Override
 		protected int writeToOutputStream(DataBuffer dataBuffer) throws IOException {
-			ByteBuffer input = dataBuffer.toByteBuffer();
+			OutputStream output = getOutputStream();
-			int len = input.remaining();
+			if (jetty11Present) {
-			ServletResponse response = getNativeResponse();
+				if (output instanceof HttpOutput httpOutput) {
-			((HttpOutput) response.getOutputStream()).write(input);
+					ByteBuffer input = dataBuffer.toByteBuffer();
-			return len;
+					int len = input.remaining();
+					httpOutput.write(input);
+					return len;
+				}
+			}
+			/* Jetty 12: see spring-web.gradle
+			else if (jetty12Present) {
+				if (output instanceof org.eclipse.jetty.ee10.servlet.HttpOutput httpOutput) {
+					ByteBuffer input = dataBuffer.toByteBuffer();
+					int len = input.remaining();
+					httpOutput.write(input);
+					return len;
+				}
+			}
+			*/
+			return super.writeToOutputStream(dataBuffer);
 		}
 
 		@Override
 		protected void applyHeaders() {
 			HttpServletResponse response = getNativeResponse();
+
 			MediaType contentType = null;
 			try {
 				contentType = getHeaders().getContentType();
@@ -156,10 +205,12 @@ public class JettyHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 			if (response.getContentType() == null && contentType != null) {
 				response.setContentType(contentType.toString());
 			}
+
 			Charset charset = (contentType != null ? contentType.getCharset() : null);
 			if (response.getCharacterEncoding() == null && charset != null) {
 				response.setCharacterEncoding(charset.name());
 			}
+
 			long contentLength = getHeaders().getContentLength();
 			if (contentLength != -1) {
 				response.setContentLengthLong(contentLength);

spring-web/src/main/java/org/springframework/http/server/reactive/ServletServerHttpRequest.java

@@ -56,6 +56,7 @@ import org.springframework.util.StringUtils;
  * Adapt {@link ServerHttpRequest} to the Servlet {@link HttpServletRequest}.
  *
  * @author Rossen Stoyanchev
+ * @author Juergen Hoeller
  * @since 5.0
  */
 class ServletServerHttpRequest extends AbstractServerHttpRequest {
@@ -65,6 +66,8 @@ class ServletServerHttpRequest extends AbstractServerHttpRequest {
 
 	private final HttpServletRequest request;
 
+	private final ServletInputStream inputStream;
+
 	private final RequestBodyPublisher bodyPublisher;
 
 	private final Object cookieLock = new Object();
@@ -99,8 +102,8 @@ class ServletServerHttpRequest extends AbstractServerHttpRequest {
 		this.asyncListener = new RequestAsyncListener();
 
 		// Tomcat expects ReadListener registration on initial thread
-		ServletInputStream inputStream = request.getInputStream();
+		this.inputStream = request.getInputStream();
-		this.bodyPublisher = new RequestBodyPublisher(inputStream);
+		this.bodyPublisher = new RequestBodyPublisher(this.inputStream);
 		this.bodyPublisher.registerReadListener();
 	}
 
@@ -231,6 +234,13 @@ class ServletServerHttpRequest extends AbstractServerHttpRequest {
 		return this.asyncListener;
 	}
 
+	/**
+	 * Return the {@link ServletInputStream} for the current response.
+	 */
+	protected final ServletInputStream getInputStream() {
+		return this.inputStream;
+	}
+
 	/**
 	 * Read from the request body InputStream and return a DataBuffer.
 	 * Invoked only when {@link ServletInputStream#isReady()} returns "true".
@@ -239,7 +249,7 @@ class ServletServerHttpRequest extends AbstractServerHttpRequest {
 	 * or {@link #EOF_BUFFER} if the input stream returned -1.
 	 */
 	DataBuffer readFromInputStream() throws IOException {
-		int read = this.request.getInputStream().read(this.buffer);
+		int read = this.inputStream.read(this.buffer);
 		logBytesRead(read);
 
 		if (read > 0) {

spring-web/src/main/java/org/springframework/http/server/reactive/ServletServerHttpResponse.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -44,6 +44,7 @@ import org.springframework.util.Assert;
  * Adapt {@link ServerHttpResponse} to the Servlet {@link HttpServletResponse}.
  *
  * @author Rossen Stoyanchev
+ * @author Juergen Hoeller
  * @since 5.0
  */
 class ServletServerHttpResponse extends AbstractListenerServerHttpResponse {
@@ -185,6 +186,13 @@ class ServletServerHttpResponse extends AbstractListenerServerHttpResponse {
 		return processor;
 	}
 
+	/**
+	 * Return the {@link ServletOutputStream} for the current response.
+	 */
+	protected final ServletOutputStream getOutputStream() {
+		return this.outputStream;
+	}
+
 	/**
 	 * Write the DataBuffer to the response body OutputStream.
 	 * Invoked only when {@link ServletOutputStream#isReady()} returns "true"

spring-web/src/main/java/org/springframework/http/server/reactive/TomcatHttpHandlerAdapter.java

@@ -23,9 +23,6 @@ import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 
 import jakarta.servlet.AsyncContext;
-import jakarta.servlet.ServletInputStream;
-import jakarta.servlet.ServletRequest;
-import jakarta.servlet.ServletResponse;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletRequestWrapper;
 import jakarta.servlet.http.HttpServletResponse;
@@ -57,7 +54,6 @@ import org.springframework.util.ReflectionUtils;
  */
 public class TomcatHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
-
 	public TomcatHttpHandlerAdapter(HttpHandler httpHandler) {
 		super(httpHandler);
 	}
@@ -130,11 +126,11 @@ public class TomcatHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
 		@Override
 		protected DataBuffer readFromInputStream() throws IOException {
-			ServletInputStream inputStream = ((ServletRequest) getNativeRequest()).getInputStream();
+			if (!(getInputStream() instanceof CoyoteInputStream coyoteInputStream)) {
-			if (!(inputStream instanceof CoyoteInputStream coyoteInputStream)) {
 				// It's possible InputStream can be wrapped, preventing use of CoyoteInputStream
 				return super.readFromInputStream();
 			}
+
 			ByteBuffer byteBuffer = this.factory.isDirect() ?
 					ByteBuffer.allocateDirect(this.bufferSize) :
 					ByteBuffer.allocate(this.bufferSize);
@@ -198,6 +194,7 @@ public class TomcatHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 		@Override
 		protected void applyHeaders() {
 			HttpServletResponse response = getNativeResponse();
+
 			MediaType contentType = null;
 			try {
 				contentType = getHeaders().getContentType();
@@ -210,10 +207,12 @@ public class TomcatHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 				response.setContentType(contentType.toString());
 			}
 			getHeaders().remove(HttpHeaders.CONTENT_TYPE);
+
 			Charset charset = (contentType != null ? contentType.getCharset() : null);
 			if (response.getCharacterEncoding() == null && charset != null) {
 				response.setCharacterEncoding(charset.name());
 			}
+
 			long contentLength = getHeaders().getContentLength();
 			if (contentLength != -1) {
 				response.setContentLengthLong(contentLength);
@@ -223,10 +222,13 @@ public class TomcatHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
 		@Override
 		protected int writeToOutputStream(DataBuffer dataBuffer) throws IOException {
+			if (!(getOutputStream() instanceof CoyoteOutputStream coyoteOutputStream)) {
+				return super.writeToOutputStream(dataBuffer);
+			}
+
 			ByteBuffer input = dataBuffer.toByteBuffer();
 			int len = input.remaining();
-			ServletResponse response = getNativeResponse();
+			coyoteOutputStream.write(input);
-			((CoyoteOutputStream) response.getOutputStream()).write(input);
 			return len;
 		}
 	}

spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/JettyXhrTransport.java

@@ -20,6 +20,7 @@ import java.io.ByteArrayOutputStream;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.util.Enumeration;
+import java.util.Iterator;
 import java.util.concurrent.CompletableFuture;
 
 import org.eclipse.jetty.client.HttpClient;
@@ -171,9 +172,9 @@ public class JettyXhrTransport extends AbstractXhrTransport implements Lifecycle
 
 	private static HttpHeaders toHttpHeaders(HttpFields httpFields) {
 		HttpHeaders responseHeaders = new HttpHeaders();
-		Enumeration<String> names = httpFields.getFieldNames();
+		Iterator<String> names = httpFields.getFieldNamesCollection().iterator();
-		while (names.hasMoreElements()) {
+		while (names.hasNext()) {
-			String name = names.nextElement();
+			String name = names.next();
 			Enumeration<String> values = httpFields.getValues(name);
 			while (values.hasMoreElements()) {
 				String value = values.nextElement();