Add LogFormatUtils

1. Helper method to eliminate duplication in formatting (de-)serialized
   values for logging introduced with prior commit #e62298.

2. Helper method for TRACE vs DEBUG logging with different details.

Issue: SPR-17254

spring-core/src/main/java/org/springframework/core/codec/CharSequenceEncoder.java

@@ -28,6 +28,7 @@ import reactor.core.publisher.Flux;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;
@@ -68,15 +69,11 @@ public final class CharSequenceEncoder extends AbstractEncoder<CharSequence> {
 		Charset charset = getCharset(mimeType);
 
 		return Flux.from(inputStream).map(charSequence -> {
-			if (logger.isDebugEnabled() && !Hints.isLoggingSuppressed(hints)) {
-				String logPrefix = Hints.getLogPrefix(hints);
-				String s = logPrefix + "Writing " + formatValue(charSequence, logger.isTraceEnabled());
-				if (logger.isTraceEnabled()) {
-					logger.trace(s);
-				}
-				else {
-					logger.debug(s);
-				}
+			if (!Hints.isLoggingSuppressed(hints)) {
+				LogFormatUtils.traceDebug(logger, traceOn -> {
+					String formatted = LogFormatUtils.formatValue(charSequence, !traceOn);
+					return Hints.getLogPrefix(hints) + "Writing " + formatted;
+				});
 			}
 			CharBuffer charBuffer = CharBuffer.wrap(charSequence);
 			ByteBuffer byteBuffer = charset.encode(charBuffer);
@@ -95,14 +92,6 @@ public final class CharSequenceEncoder extends AbstractEncoder<CharSequence> {
 		return charset;
 	}
 
-	private String formatValue(@Nullable Object value, boolean logFullValue) {
-		if (value == null) {
-			return "";
-		}
-		String s = value instanceof CharSequence ? "\"" + value + "\"" : value.toString();
-		return logFullValue || s.length() < 100 ? s : s.substring(0, 100) + " (truncated)...";
-	}
-
 
 	/**
 	 * Create a {@code CharSequenceEncoder} that supports only "text/plain".

spring-core/src/main/java/org/springframework/core/codec/StringDecoder.java

@@ -33,6 +33,7 @@ import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.MimeType;
@@ -206,15 +207,10 @@ public final class StringDecoder extends AbstractDataBufferDecoder<String> {
 		CharBuffer charBuffer = charset.decode(dataBuffer.asByteBuffer());
 		DataBufferUtils.release(dataBuffer);
 		String value = charBuffer.toString();
-		if (logger.isDebugEnabled()) {
-			String s = Hints.getLogPrefix(hints) + "Decoded " + formatValue(value, logger.isTraceEnabled());
-			if (logger.isTraceEnabled()) {
-				logger.trace(s);
-			}
-			else {
-				logger.debug(s);
-			}
-		}
+		LogFormatUtils.traceDebug(logger, traceOn -> {
+			String formatted = LogFormatUtils.formatValue(value, !traceOn);
+			return Hints.getLogPrefix(hints) + "Decoded " + formatted;
+		});
 		return value;
 	}
 
@@ -227,14 +223,6 @@ public final class StringDecoder extends AbstractDataBufferDecoder<String> {
 		}
 	}
 
-	private String formatValue(@Nullable Object value, boolean logFullValue) {
-		if (value == null) {
-			return "";
-		}
-		String s = value instanceof CharSequence ? "\"" + value + "\"" : value.toString();
-		return logFullValue || s.length() < 100 ? s : s.substring(0, 100) + " (truncated)...";
-	}
-
 
 	/**
 	 * Create a {@code StringDecoder} for {@code "text/plain"}.

spring-core/src/main/java/org/springframework/core/log/LogFormatUtils.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2002-2018 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.core.log;
+
+import java.util.function.Function;
+
+import org.apache.commons.logging.Log;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * Utility methods for formatting and logging messages.
+ *
+ * <p>Mainly for internal use within the framework with Apache Commons Logging,
+ * typically in the form of the {@code spring-jcl} bridge but also compatible
+ * with other Commons Logging bridges.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.1
+ */
+public final class LogFormatUtils {
+
+	private LogFormatUtils() {
+	}
+
+
+	/**
+	 * Format the given value via {@code toString()}, quoting it if it is a
+	 * {@link CharSequence}, and possibly truncating at 100 if limitLength is
+	 * set to true.
+	 * @param value the value to format
+	 * @param limitLength whether to truncate large formatted values (over 100).
+	 * @return the formatted value
+	 * @since 5.1
+	 */
+	public static String formatValue(@Nullable Object value, boolean limitLength) {
+		if (value == null) {
+			return "";
+		}
+		String s = value instanceof CharSequence ? "\"" + value + "\"" : value.toString();
+		return limitLength && s.length() > 100 ? s.substring(0, 100) + " (truncated)..." : s;
+	}
+
+	/**
+	 * Use this to log a message with different levels of detail (or different
+	 * messages) at TRACE vs DEBUG log levels. Effectively, a substitute for:
+	 * <pre class="code">
+	 * if (logger.isDebugEnabled()) {
+	 *	String s = logger.isTraceEnabled() ? "..." : "...";
+	 *	if (logger.isTraceEnabled()) {
+	 *		logger.trace(s);
+	 *	}
+	 *	else {
+	 *		logger.debug(s);
+	 *	}
+	 * }
+	 * </pre>
+	 * @param logger the logger to use to log the message
+	 * @param messageFactory function that accepts a boolean set to the value
+	 * of {@link Log#isTraceEnabled()}.
+	 */
+	public static void traceDebug(Log logger, Function<Boolean, String> messageFactory) {
+		if (logger.isDebugEnabled()) {
+			String logMessage = messageFactory.apply(logger.isTraceEnabled());
+			if (logger.isTraceEnabled()) {
+				logger.trace(logMessage);
+			}
+			else {
+				logger.debug(logMessage);
+			}
+		}
+	}
+
+}

spring-web/src/main/java/org/springframework/http/codec/FormHttpMessageReader.java

@@ -31,6 +31,7 @@ import reactor.core.publisher.Mono;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBufferUtils;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.MediaType;
 import org.springframework.http.ReactiveHttpInputMessage;
 import org.springframework.lang.Nullable;
@@ -114,18 +115,10 @@ public class FormHttpMessageReader extends LoggingCodecSupport
 	}
 
 	private void logFormData(MultiValueMap<String, String> formData, Map<String, Object> hints) {
-		if (logger.isDebugEnabled()) {
-			String s = Hints.getLogPrefix(hints) + "Read " +
+		LogFormatUtils.traceDebug(logger, traceOn -> Hints.getLogPrefix(hints) + "Read " +
 				(isEnableLoggingRequestDetails() ?
-							formatValue(formData, logger.isTraceEnabled()) :
-							"form fields " + formData.keySet() + " (content masked)");
-			if (logger.isTraceEnabled()) {
-				logger.trace(s);
-			}
-			else {
-				logger.debug(s);
-			}
-		}
+						LogFormatUtils.formatValue(formData, !traceOn) :
+						"form fields " + formData.keySet() + " (content masked)"));
 	}
 
 	private Charset getMediaTypeCharset(@Nullable MediaType mediaType) {

spring-web/src/main/java/org/springframework/http/codec/FormHttpMessageWriter.java

@@ -31,6 +31,7 @@ import reactor.core.publisher.Mono;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.MediaType;
 import org.springframework.http.ReactiveHttpOutputMessage;
 import org.springframework.lang.Nullable;
@@ -131,18 +132,7 @@ public class FormHttpMessageWriter extends LoggingCodecSupport
 		Assert.notNull(charset, "No charset"); // should never occur
 
 		return Mono.from(inputStream).flatMap(form -> {
-			if (logger.isDebugEnabled()) {
-				String s = Hints.getLogPrefix(hints) + "Writing " +
-						(isEnableLoggingRequestDetails() ?
-								formatValue(form, logger.isTraceEnabled()) :
-								"form fields " + form.keySet() + " (content masked)");
-				if (logger.isTraceEnabled()) {
-					logger.trace(s);
-				}
-				else {
-					logger.debug(s);
-				}
-			}
+			logFormData(form, hints);
 			String value = serializeForm(form, charset);
 			ByteBuffer byteBuffer = charset.encode(value);
 			DataBuffer buffer = message.bufferFactory().wrap(byteBuffer);
@@ -163,6 +153,13 @@ public class FormHttpMessageWriter extends LoggingCodecSupport
 		}
 	}
 
+	private void logFormData(MultiValueMap<String, String> form, Map<String, Object> hints) {
+		LogFormatUtils.traceDebug(logger, traceOn -> Hints.getLogPrefix(hints) + "Writing " +
+				(isEnableLoggingRequestDetails() ?
+						LogFormatUtils.formatValue(form, !traceOn) :
+						"form fields " + form.keySet() + " (content masked)"));
+	}
+
 	protected String serializeForm(MultiValueMap<String, String> formData, Charset charset) {
 		StringBuilder builder = new StringBuilder();
 		formData.forEach((name, values) ->

spring-web/src/main/java/org/springframework/http/codec/LoggingCodecSupport.java

@@ -19,7 +19,6 @@ package org.springframework.http.codec;
 import org.apache.commons.logging.Log;
 
 import org.springframework.http.HttpLogging;
-import org.springframework.lang.Nullable;
 
 /**
  * Base class for {@link org.springframework.core.codec.Encoder},
@@ -56,20 +55,4 @@ public class LoggingCodecSupport {
 		return this.enableLoggingRequestDetails;
 	}
 
-	/**
-	 * Format the given value via {{toString()}}, either in full or truncated
-	 * if it has 100 or more characters.
-	 * @param value the value to format
-	 * @param logFullValue whether to log in full or truncate if necessary
-	 * @return the formatted value
-	 * @since 5.1
-	 */
-	protected String formatValue(@Nullable Object value, boolean logFullValue) {
-		if (value == null) {
-			return "";
-		}
-		String s = value instanceof CharSequence ? "\"" + value + "\"" : value.toString();
-		return logFullValue || s.length() < 100 ? s : s.substring(0, 100) + " (truncated)...";
-	}
-
 }

spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Decoder.java

@@ -38,6 +38,7 @@ import org.springframework.core.codec.CodecException;
 import org.springframework.core.codec.DecodingException;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.codec.HttpMessageDecoder;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpResponse;
@@ -115,15 +116,11 @@ public abstract class AbstractJackson2Decoder extends Jackson2CodecSupport imple
 		return tokens.map(tokenBuffer -> {
 			try {
 				Object value = reader.readValue(tokenBuffer.asParser(getObjectMapper()));
-				if (logger.isDebugEnabled() && !Hints.isLoggingSuppressed(hints)) {
-					boolean traceOn = logger.isTraceEnabled();
-					String s = Hints.getLogPrefix(hints) + "Decoded [" + formatValue(value, traceOn) + "]";
-					if (traceOn) {
-						logger.trace(s);
-					}
-					else {
-						logger.debug(s);
-					}
+				if (!Hints.isLoggingSuppressed(hints)) {
+					LogFormatUtils.traceDebug(logger, traceOn -> {
+						String formatted = LogFormatUtils.formatValue(value, !traceOn);
+						return Hints.getLogPrefix(hints) + "Decoded [" + formatted + "]";
+					});
 				}
 				return value;
 			}

spring-web/src/main/java/org/springframework/http/codec/json/AbstractJackson2Encoder.java

@@ -44,6 +44,7 @@ import org.springframework.core.codec.EncodingException;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.HttpMessageEncoder;
 import org.springframework.http.server.reactive.ServerHttpRequest;
@@ -141,15 +142,11 @@ public abstract class AbstractJackson2Encoder extends Jackson2CodecSupport imple
 	private DataBuffer encodeValue(Object value, @Nullable MimeType mimeType, DataBufferFactory bufferFactory,
 			ResolvableType elementType, @Nullable Map<String, Object> hints, JsonEncoding encoding) {
 
-		if (logger.isDebugEnabled() && !Hints.isLoggingSuppressed(hints)) {
-			boolean traceOn = logger.isTraceEnabled();
-			String s = Hints.getLogPrefix(hints) + "Encoding [" + formatValue(value, traceOn) + "]";
-			if (traceOn) {
-				logger.trace(s);
-			}
-			else {
-				logger.debug(s);
-			}
+		if (!Hints.isLoggingSuppressed(hints)) {
+			LogFormatUtils.traceDebug(logger, traceOn -> {
+				String formatted = LogFormatUtils.formatValue(value, !traceOn);
+				return Hints.getLogPrefix(hints) + "Encoding [" + formatted + "]";
+			});
 		}
 
 		JavaType javaType = getJavaType(elementType.getType(), null);

spring-web/src/main/java/org/springframework/http/codec/json/Jackson2CodecSupport.java

@@ -125,12 +125,4 @@ public abstract class Jackson2CodecSupport {
 	@Nullable
 	protected abstract <A extends Annotation> A getAnnotation(MethodParameter parameter, Class<A> annotType);
 
-	String formatValue(@Nullable Object value, boolean logFullValue) {
-		if (value == null) {
-			return "";
-		}
-		String s = value instanceof CharSequence ? "\"" + value + "\"" : value.toString();
-		return logFullValue || s.length() < 100 ? s : s.substring(0, 100) + " (truncated)...";
-	}
-
 }

spring-web/src/main/java/org/springframework/http/codec/multipart/MultipartHttpMessageReader.java

@@ -28,6 +28,7 @@ import reactor.core.publisher.Mono;
 
 import org.springframework.core.ResolvableType;
 import org.springframework.core.codec.Hints;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.MediaType;
 import org.springframework.http.ReactiveHttpInputMessage;
 import org.springframework.http.codec.HttpMessageReader;
@@ -94,18 +95,10 @@ public class MultipartHttpMessageReader extends LoggingCodecSupport
 		return this.partReader.read(elementType, inputMessage, allHints)
 				.collectMultimap(Part::name)
 				.doOnNext(map -> {
-					if (logger.isDebugEnabled()) {
-						String s = Hints.getLogPrefix(hints) + "Parsed " +
+					LogFormatUtils.traceDebug(logger, traceOn -> Hints.getLogPrefix(hints) + "Parsed " +
 							(isEnableLoggingRequestDetails() ?
-										formatValue(map, logger.isTraceEnabled()) :
-										"parts " + map.keySet() + " (content masked)");
-						if (logger.isTraceEnabled()) {
-							logger.trace(s);
-						}
-						else {
-							logger.debug(s);
-						}
-					}
+									LogFormatUtils.formatValue(map, !traceOn) :
+									"parts " + map.keySet() + " (content masked)"));
 				})
 				.map(this::toMultiValueMap);
 	}

spring-web/src/main/java/org/springframework/http/codec/multipart/MultipartHttpMessageWriter.java

@@ -41,6 +41,7 @@ import org.springframework.core.io.Resource;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
@@ -225,18 +226,10 @@ public class MultipartHttpMessageWriter extends LoggingCodecSupport
 
 		outputMessage.getHeaders().setContentType(new MediaType(MediaType.MULTIPART_FORM_DATA, params));
 
-		if (logger.isDebugEnabled()) {
-			String s = Hints.getLogPrefix(hints) + "Encoding " +
+		LogFormatUtils.traceDebug(logger, traceOn -> Hints.getLogPrefix(hints) + "Encoding " +
 				(isEnableLoggingRequestDetails() ?
-							formatValue(map, logger.isTraceEnabled()) :
-							"parts " + map.keySet() + " (content masked)");
-			if (logger.isTraceEnabled()) {
-				logger.trace(s);
-			}
-			else {
-				logger.debug(s);
-			}
-		}
+						LogFormatUtils.formatValue(map, !traceOn) :
+						"parts " + map.keySet() + " (content masked)"));
 
 		Flux<DataBuffer> body = Flux.fromIterable(map.entrySet())
 				.concatMap(entry -> encodePartValues(boundary, entry.getKey(), entry.getValue()))

spring-web/src/main/java/org/springframework/http/codec/multipart/SynchronossPartHttpMessageReader.java

@@ -50,6 +50,7 @@ import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
 import org.springframework.http.ReactiveHttpInputMessage;
@@ -95,17 +96,11 @@ public class SynchronossPartHttpMessageReader extends LoggingCodecSupport implem
 	public Flux<Part> read(ResolvableType elementType, ReactiveHttpInputMessage message, Map<String, Object> hints) {
 		return Flux.create(new SynchronossPartGenerator(message, this.bufferFactory, this.streamStorageFactory))
 				.doOnNext(part -> {
-					if (logger.isDebugEnabled() && !Hints.isLoggingSuppressed(hints)) {
-						String s = Hints.getLogPrefix(hints) + "Parsed " +
+					if (!Hints.isLoggingSuppressed(hints)) {
+						LogFormatUtils.traceDebug(logger, traceOn -> Hints.getLogPrefix(hints) + "Parsed " +
 								(isEnableLoggingRequestDetails() ?
-										formatValue(part, logger.isTraceEnabled()) :
-										"parts '" + part.name() + "' (content masked)");
-						if (logger.isTraceEnabled()) {
-							logger.trace(s);
-						}
-						else {
-							logger.debug(s);
-						}
+										LogFormatUtils.formatValue(part, !traceOn) :
+										"parts '" + part.name() + "' (content masked)"));
 					}
 				});
 	}

spring-web/src/main/java/org/springframework/http/codec/xml/Jaxb2XmlDecoder.java

@@ -42,6 +42,7 @@ import org.springframework.core.codec.CodecException;
 import org.springframework.core.codec.DecodingException;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -107,16 +108,10 @@ public class Jaxb2XmlDecoder extends AbstractDecoder<Object> {
 
 		return splitEvents.map(events -> {
 			Object value = unmarshal(events, outputClass);
-			if (logger.isDebugEnabled()) {
-				boolean traceOn = logger.isTraceEnabled();
-				String s = Hints.getLogPrefix(hints) + "Decoded [" + formatValue(value, traceOn) + "]";
-				if (traceOn) {
-					logger.trace(s);
-				}
-				else {
-					logger.debug(s);
-				}
-			}
+			LogFormatUtils.traceDebug(logger, traceOn -> {
+				String formatted = LogFormatUtils.formatValue(value, !traceOn);
+				return Hints.getLogPrefix(hints) + "Decoded [" + formatted + "]";
+			});
 			return value;
 		});
 	}
@@ -213,14 +208,6 @@ public class Jaxb2XmlDecoder extends AbstractDecoder<Object> {
 		return xmlEventFlux.flatMap(new SplitFunction(desiredName));
 	}
 
-	String formatValue(@Nullable Object value, boolean logFullValue) {
-		if (value == null) {
-			return "";
-		}
-		String s = value instanceof CharSequence ? "\"" + value + "\"" : value.toString();
-		return logFullValue || s.length() < 100 ? s : s.substring(0, 100) + " (truncated)...";
-	}
-
 
 	private static class SplitFunction implements Function<XMLEvent, Publisher<? extends List<XMLEvent>>> {
 

spring-web/src/main/java/org/springframework/http/codec/xml/Jaxb2XmlEncoder.java

@@ -34,6 +34,7 @@ import org.springframework.core.codec.EncodingException;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.MimeType;
@@ -78,15 +79,11 @@ public class Jaxb2XmlEncoder extends AbstractSingleValueEncoder<Object> {
 	protected Flux<DataBuffer> encode(Object value, DataBufferFactory dataBufferFactory,
 			ResolvableType type, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
 		try {
-			if (logger.isDebugEnabled() && !Hints.isLoggingSuppressed(hints)) {
-				boolean traceOn = logger.isTraceEnabled();
-				String s = Hints.getLogPrefix(hints) + "Encoding [" + formatValue(value, traceOn) + "]";
-				if (traceOn) {
-					logger.trace(s);
-				}
-				else {
-					logger.debug(s);
-				}
+			if (!Hints.isLoggingSuppressed(hints)) {
+				LogFormatUtils.traceDebug(logger, traceOn -> {
+					String formatted = LogFormatUtils.formatValue(value, !traceOn);
+					return Hints.getLogPrefix(hints) + "Encoding [" + formatted + "]";
+				});
 			}
 			DataBuffer buffer = dataBufferFactory.allocateBuffer(1024);
 			OutputStream outputStream = buffer.asOutputStream();
@@ -104,12 +101,4 @@ public class Jaxb2XmlEncoder extends AbstractSingleValueEncoder<Object> {
 		}
 	}
 
-	String formatValue(@Nullable Object value, boolean logFullValue) {
-		if (value == null) {
-			return "";
-		}
-		String s = value instanceof CharSequence ? "\"" + value + "\"" : value.toString();
-		return logFullValue || s.length() < 100 ? s : s.substring(0, 100) + " (truncated)...";
-	}
-
 }

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

@@ -49,7 +49,8 @@ public abstract class AbstractListenerWriteFlushProcessor<T> implements Processo
 	 * @see AbstractListenerWriteProcessor#rsWriteLogger
 	 * @see WriteResultPublisher#rsWriteResultLogger
 	 */
-	protected static final Log rsWriteFlushLogger = LogDelegateFactory.getHiddenLog(AbstractListenerWriteFlushProcessor.class);
+	protected static final Log rsWriteFlushLogger =
+			LogDelegateFactory.getHiddenLog(AbstractListenerWriteFlushProcessor.class);
 
 
 	private final AtomicReference<State> state = new AtomicReference<>(State.UNSUBSCRIBED);

spring-web/src/main/java/org/springframework/web/multipart/commons/CommonsFileUploadSupport.java

@@ -31,6 +31,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.core.io.Resource;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.MediaType;
 import org.springframework.lang.Nullable;
 import org.springframework.util.LinkedMultiValueMap;
@@ -281,16 +282,11 @@ public abstract class CommonsFileUploadSupport {
 				// multipart file field
 				CommonsMultipartFile file = createMultipartFile(fileItem);
 				multipartFiles.add(file.getName(), file);
-				if (logger.isDebugEnabled()) {
-					String message = "Part '" + file.getName() + "', " +
-							"size " + file.getSize() + " bytes, filename='" + file.getOriginalFilename() + "'";
-					if (logger.isTraceEnabled()) {
-						logger.trace(message + ", storage=" + file.getStorageDescription());
-					}
-					else {
-						logger.debug(message);
-					}
-				}
+				LogFormatUtils.traceDebug(logger, traceOn ->
+						"Part '" + file.getName() + "', size " + file.getSize() +
+								" bytes, filename='" + file.getOriginalFilename() + "'" +
+								(traceOn ? ", storage=" + file.getStorageDescription() : "")
+				);
 			}
 		}
 		return new MultipartParsingResult(multipartFiles, multipartParameters, multipartParameterContentTypes);
@@ -323,16 +319,10 @@ public abstract class CommonsFileUploadSupport {
 				if (file instanceof CommonsMultipartFile) {
 					CommonsMultipartFile cmf = (CommonsMultipartFile) file;
 					cmf.getFileItem().delete();
-					if (logger.isDebugEnabled()) {
-						String filename = cmf.getOriginalFilename();
-						String message = "Cleaning up part '" + cmf.getName() + "', filename '" + filename + "'";
-						if (logger.isTraceEnabled()) {
-							logger.trace(message + ", stored " + cmf.getStorageDescription());
-						}
-						else {
-							logger.debug(message);
-						}
-					}
+					LogFormatUtils.traceDebug(logger, traceOn ->
+							"Cleaning up part '" + cmf.getName() +
+									"', filename '" + cmf.getOriginalFilename() + "'" +
+									(traceOn ? ", stored " + cmf.getStorageDescription() : ""));
 				}
 			}
 		}

spring-web/src/main/java/org/springframework/web/multipart/commons/CommonsMultipartFile.java

@@ -29,6 +29,7 @@ import org.apache.commons.fileupload.disk.DiskFileItem;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.util.FileCopyUtils;
 import org.springframework.util.StreamUtils;
 import org.springframework.web.multipart.MultipartFile;
@@ -165,20 +166,15 @@ public class CommonsMultipartFile implements MultipartFile, Serializable {
 
 		try {
 			this.fileItem.write(dest);
-			if (logger.isDebugEnabled()) {
+			LogFormatUtils.traceDebug(logger, traceOn -> {
 				String action = "transferred";
 				if (!this.fileItem.isInMemory()) {
 					action = (isAvailable() ? "copied" : "moved");
 				}
-				String message = "Part '" + getName() + "',  filename '" + getOriginalFilename() + "'";
-				if (logger.isTraceEnabled()) {
-					logger.trace(message + ", stored " + getStorageDescription() + ": " + action +
-							" to [" + dest.getAbsolutePath() + "]");
-				}
-				else {
-					logger.debug(message + ": " + action + " to [" + dest.getAbsolutePath() + "]");
-				}
-			}
+				return "Part '" + getName() + "',  filename '" + getOriginalFilename() + "'" +
+						(traceOn ? ", stored " + getStorageDescription() : "") +
+						": " + action + " to [" + dest.getAbsolutePath() + "]";
+			});
 		}
 		catch (FileUploadException ex) {
 			throw new IllegalStateException(ex.getMessage(), ex);

spring-web/src/main/java/org/springframework/web/server/adapter/HttpWebHandlerAdapter.java

@@ -26,6 +26,7 @@ import reactor.core.publisher.Mono;
 
 import org.springframework.context.ApplicationContext;
 import org.springframework.core.NestedExceptionUtils;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.codec.LoggingCodecSupport;
@@ -237,7 +238,10 @@ public class HttpWebHandlerAdapter extends WebHandlerDecorator implements HttpHa
 		}
 
 		ServerWebExchange exchange = createExchange(request, response);
-		logExchange(exchange);
+
+		LogFormatUtils.traceDebug(logger, traceOn ->
+				exchange.getLogPrefix() + formatRequest(exchange.getRequest()) +
+						(traceOn ? ", headers=" + formatHeaders(exchange.getRequest().getHeaders()) : ""));
 
 		return getDelegate().handle(exchange)
 				.doOnSuccess(aVoid -> logResponse(exchange))
@@ -250,19 +254,6 @@ public class HttpWebHandlerAdapter extends WebHandlerDecorator implements HttpHa
 				getCodecConfigurer(), getLocaleContextResolver(), this.applicationContext);
 	}
 
-	private void logExchange(ServerWebExchange exchange) {
-		if (logger.isDebugEnabled()) {
-			String logPrefix = exchange.getLogPrefix();
-			ServerHttpRequest request = exchange.getRequest();
-			if (logger.isTraceEnabled()) {
-				logger.trace(logPrefix + formatRequest(request) + ", headers=" + formatHeaders(request.getHeaders()));
-			}
-			else {
-				logger.debug(logPrefix + formatRequest(request));
-			}
-		}
-	}
-
 	private String formatRequest(ServerHttpRequest request) {
 		String rawQuery = request.getURI().getRawQuery();
 		String query = StringUtils.hasText(rawQuery) ? "?" + rawQuery : "";
@@ -270,18 +261,11 @@ public class HttpWebHandlerAdapter extends WebHandlerDecorator implements HttpHa
 	}
 
 	private void logResponse(ServerWebExchange exchange) {
-		if (logger.isDebugEnabled()) {
-			String logPrefix = exchange.getLogPrefix();
-			ServerHttpResponse response = exchange.getResponse();
-			HttpStatus status = response.getStatusCode();
-			String message = "Completed " + (status != null ? status : "200 OK");
-			if (logger.isTraceEnabled()) {
-				logger.trace(logPrefix + message + ", headers=" + formatHeaders(response.getHeaders()));
-			}
-			else {
-				logger.debug(logPrefix + message);
-			}
-		}
+		LogFormatUtils.traceDebug(logger, traceOn -> {
+			HttpStatus status = exchange.getResponse().getStatusCode();
+			return exchange.getLogPrefix() + "Completed " + (status != null ? status : "200 OK") +
+					(traceOn ? ", headers=" + formatHeaders(exchange.getResponse().getHeaders()) : "");
+		});
 	}
 
 	private String formatHeaders(HttpHeaders responseHeaders) {

spring-webflux/src/main/java/org/springframework/web/reactive/function/client/ExchangeFunctions.java

@@ -22,6 +22,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import reactor.core.publisher.Mono;
 
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
@@ -109,29 +110,19 @@ public abstract class ExchangeFunctions {
 		}
 
 		private void logRequest(ClientRequest request) {
-			if (logger.isDebugEnabled()) {
-				String message = request.logPrefix() + "HTTP " + request.method() + " " + request.url();
-				if (logger.isTraceEnabled()) {
-					logger.trace(message + ", headers=" + formatHeaders(request.headers()));
-				}
-				else {
-					logger.debug(message);
-				}
-			}
+			LogFormatUtils.traceDebug(logger, traceOn ->
+					request.logPrefix() + "HTTP " + request.method() + " " + request.url() +
+							(traceOn ? ", headers=" + formatHeaders(request.headers()) : "")
+			);
 		}
 
 		private void logResponse(ClientHttpResponse response, String logPrefix) {
-			if (logger.isDebugEnabled()) {
+			LogFormatUtils.traceDebug(logger, traceOn -> {
 				int code = response.getRawStatusCode();
 				HttpStatus status = HttpStatus.resolve(code);
-				String message = logPrefix + "Response " + (status != null ? status : code);
-				if (logger.isTraceEnabled()) {
-					logger.trace(message + ", headers=" + formatHeaders(response.getHeaders()));
-				}
-				else {
-					logger.debug(message);
-				}
-			}
+				return logPrefix + "Response " + (status != null ? status : code) +
+						(traceOn ? ", headers=" + formatHeaders(response.getHeaders()) : "");
+			});
 		}
 
 		private String formatHeaders(HttpHeaders headers) {

spring-webmvc/src/main/java/org/springframework/web/servlet/DispatcherServlet.java

@@ -48,6 +48,7 @@ import org.springframework.context.i18n.LocaleContext;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.support.PropertiesLoaderUtils;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.server.ServletServerHttpRequest;
 import org.springframework.lang.Nullable;
 import org.springframework.ui.context.ThemeSource;
@@ -951,7 +952,7 @@ public class DispatcherServlet extends FrameworkServlet {
 	}
 
 	private void logRequest(HttpServletRequest request) {
-		if (logger.isDebugEnabled()) {
+		LogFormatUtils.traceDebug(logger, traceOn -> {
 			String params;
 			if (isEnableLoggingRequestDetails()) {
 				params = request.getParameterMap().entrySet().stream()
@@ -968,19 +969,19 @@ public class DispatcherServlet extends FrameworkServlet {
 			String message = (dispatchType + request.getMethod() + " \"" + getRequestUri(request) +
 					query + "\", parameters={" + params + "}");
 
-			if (logger.isTraceEnabled()) {
+			if (traceOn) {
 				List<String> values = Collections.list(request.getHeaderNames());
 				String headers = values.size() > 0 ? "masked" : "";
 				if (isEnableLoggingRequestDetails()) {
 					headers = values.stream().map(name -> name + ":" + Collections.list(request.getHeaders(name)))
 							.collect(Collectors.joining(", "));
 				}
-				logger.trace(message + ", headers={" + headers + "} in DispatcherServlet '" + getServletName() + "'");
+				return message + ", headers={" + headers + "} in DispatcherServlet '" + getServletName() + "'";
 			}
 			else {
-				logger.debug(message);
-			}
+				return message;
 			}
+		});
 	}
 
 	/**

spring-webmvc/src/main/java/org/springframework/web/servlet/FrameworkServlet.java

@@ -1082,8 +1082,10 @@ public abstract class FrameworkServlet extends HttpServletBean implements Applic
 		if (failureCause != null) {
 			if (!initialDispatch) {
 				// FORWARD/ERROR/ASYNC: minimal message (there should be enough context already)
+				if (logger.isDebugEnabled()) {
 					logger.debug("Unresolved failure from \"" + dispatchType + "\" dispatch: " + failureCause);
 				}
+			}
 			else if (logger.isTraceEnabled()) {
 				logger.trace("Failed to complete request", failureCause);
 			}

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMessageConverterMethodArgumentResolver.java

@@ -37,6 +37,7 @@ import org.apache.commons.logging.LogFactory;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpInputMessage;
 import org.springframework.http.HttpMethod;
@@ -223,17 +224,12 @@ public abstract class AbstractMessageConverterMethodArgumentResolver implements
 			throw new HttpMediaTypeNotSupportedException(contentType, this.allSupportedMediaTypes);
 		}
 
-		if (logger.isDebugEnabled()) {
-			boolean traceOn = logger.isTraceEnabled();
-			String s = "Read \"" + contentType + "\" to [" +
-					RequestMappingHandlerAdapter.formatValue(body, traceOn) + "]";
-			if (traceOn) {
-				logger.trace(s);
-			}
-			else {
-				logger.debug(s);
-			}
-		}
+		MediaType selectedContentType = contentType;
+		Object theBody = body;
+		LogFormatUtils.traceDebug(logger, traceOn -> {
+			String formatted = LogFormatUtils.formatValue(theBody, !traceOn);
+			return "Read \"" + selectedContentType + "\" to [" + formatted + "]";
+		});
 
 		return body;
 	}

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMessageConverterMethodProcessor.java

@@ -35,6 +35,7 @@ import org.springframework.core.ResolvableType;
 import org.springframework.core.io.InputStreamResource;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.ResourceRegion;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpOutputMessage;
@@ -280,16 +281,9 @@ public abstract class AbstractMessageConverterMethodProcessor extends AbstractMe
 							(Class<? extends HttpMessageConverter<?>>) converter.getClass(),
 							inputMessage, outputMessage);
 					if (body != null) {
-						if (logger.isDebugEnabled()) {
-							boolean traceOn = logger.isTraceEnabled();
-							String s = "Writing [" + RequestMappingHandlerAdapter.formatValue(body, traceOn) + "]";
-							if (traceOn) {
-								logger.trace(s);
-							}
-							else {
-								logger.debug(s);
-							}
-						}
+						Object theBody = body;
+						LogFormatUtils.traceDebug(logger, traceOn ->
+								"Writing [" + LogFormatUtils.formatValue(theBody, traceOn) + "]");
 						addContentDispositionHeader(inputMessage, outputMessage);
 						if (genericConverter != null) {
 							genericConverter.write(body, targetType, selectedMediaType, outputMessage);

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerAdapter.java

@@ -38,6 +38,7 @@ import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
+import org.springframework.core.log.LogFormatUtils;
 import org.springframework.core.task.AsyncTaskExecutor;
 import org.springframework.core.task.SimpleAsyncTaskExecutor;
 import org.springframework.http.converter.ByteArrayHttpMessageConverter;
@@ -884,15 +885,10 @@ public class RequestMappingHandlerAdapter extends AbstractHandlerMethodAdapter
 				Object result = asyncManager.getConcurrentResult();
 				mavContainer = (ModelAndViewContainer) asyncManager.getConcurrentResultContext()[0];
 				asyncManager.clearConcurrentResult();
-				if (logger.isDebugEnabled()) {
-					String s = "Resume with async result [" + formatValue(result, logger.isTraceEnabled()) + "]";
-					if (logger.isTraceEnabled()) {
-						logger.trace(s);
-					}
-					else {
-						logger.debug(s);
-					}
-				}
+				LogFormatUtils.traceDebug(logger, traceOn -> {
+					String formatted = LogFormatUtils.formatValue(result, !traceOn);
+					return "Resume with async result [" + formatted + "]";
+				});
 				invocableMethod = invocableMethod.wrapConcurrentResult(result);
 			}
 
@@ -1024,12 +1020,4 @@ public class RequestMappingHandlerAdapter extends AbstractHandlerMethodAdapter
 		return mav;
 	}
 
-	static String formatValue(@Nullable Object body, boolean logFullBody) {
-		if (body == null) {
-			return "";
-		}
-		String s = body instanceof CharSequence ? "\"" + body + "\"" : body.toString();
-		return logFullBody || s.length() < 100 ? s : s.substring(0, 100) + " (truncated)...";
-	}
-
 }