Minor refactoring in Tomcat/Jetty adapters

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

@@ -19,14 +19,12 @@ package org.springframework.http.server.reactive;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Map;
-
 import javax.servlet.AsyncContext;
-import javax.servlet.ServletOutputStream;
 import javax.servlet.annotation.WebServlet;
-import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletResponse;
 
 import org.eclipse.jetty.server.HttpOutput;
+
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
 
@@ -68,12 +66,9 @@ public class JettyHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
 		@Override
 		protected int writeToOutputStream(DataBuffer dataBuffer) throws IOException {
-			ServletOutputStream outputStream = getServletResponse().getOutputStream();
 			ByteBuffer input = dataBuffer.asByteBuffer();
 			int len = input.remaining();
-			if (outputStream.isReady() && len > 0) {
+			((HttpOutput) getServletResponse().getOutputStream()).write(input);
-				((HttpOutput) outputStream).write(input);
-			}
 			return len;
 		}
 	}

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

@@ -180,6 +180,10 @@ public class ServletServerHttpRequest extends AbstractServerHttpRequest {
 		return Flux.from(this.bodyPublisher);
 	}
 
+	/**
+	 * Read from the request body InputStream and return a DataBuffer.
+	 * Invoked only when {@link ServletInputStream#isReady()} returns "true".
+	 */
 	protected DataBuffer readFromInputStream() throws IOException {
 		int read = this.request.getInputStream().read(this.buffer);
 		if (logger.isTraceEnabled()) {

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

@@ -132,6 +132,12 @@ public class ServletServerHttpResponse extends AbstractListenerServerHttpRespons
 		return processor;
 	}
 
+	/**
+	 * Write the DataBuffer to the response body OutputStream.
+	 * Invoked only when {@link ServletOutputStream#isReady()} returns "true"
+	 * and the readable bytes in the DataBuffer is greater than 0.
+	 * @return the number of bytes written
+	 */
 	protected int writeToOutputStream(DataBuffer dataBuffer) throws IOException {
 		ServletOutputStream outputStream = response.getOutputStream();
 		InputStream input = dataBuffer.asInputStream();
@@ -285,14 +291,13 @@ public class ServletServerHttpResponse extends AbstractListenerServerHttpRespons
 			if (this.logger.isTraceEnabled()) {
 				this.logger.trace("write: " + dataBuffer + " ready: " + ready);
 			}
-			if (ready) {
+			int remaining = dataBuffer.readableByteCount();
-				int total = dataBuffer.readableByteCount();
+			if (ready && remaining > 0) {
 				int written = writeToOutputStream(dataBuffer);
-
 				if (this.logger.isTraceEnabled()) {
-					this.logger.trace("written: " + written + " total: " + total);
+					this.logger.trace("written: " + written + " total: " + remaining);
 				}
-				return written == total;
+				return written == remaining;
 			}
 			else {
 				return false;

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

@@ -20,7 +20,6 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Map;
 import javax.servlet.AsyncContext;
-import javax.servlet.ServletOutputStream;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -100,12 +99,9 @@ public class TomcatHttpHandlerAdapter extends ServletHttpHandlerAdapter {
 
 		@Override
 		protected int writeToOutputStream(DataBuffer dataBuffer) throws IOException {
-			ServletOutputStream outputStream = getServletResponse().getOutputStream();
 			ByteBuffer input = dataBuffer.asByteBuffer();
 			int len = input.remaining();
-			if (outputStream.isReady() && len > 0) {
+			((CoyoteOutputStream) getServletResponse().getOutputStream()).write(input);
-				((CoyoteOutputStream) outputStream).write(input);
-			}
 			return len;
 		}
 	}