diff --git a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorClientHttpConnector.java b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorClientHttpConnector.java
index e3a5fa0ee06..4d470e88cab 100644
--- a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorClientHttpConnector.java
+++ b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorClientHttpConnector.java
@@ -139,7 +139,7 @@ public class ReactorClientHttpConnector implements ClientHttpConnector, SmartLif
 		HttpClient.RequestSender requestSender = this.httpClient
 				.request(io.netty.handler.codec.http.HttpMethod.valueOf(method.name()));
 
-		requestSender = (uri.isAbsolute() ? requestSender.uri(uri) : requestSender.uri(uri.toString()));
+		requestSender = setUri(requestSender, uri);
 
 		return requestSender
 				.send((request, outbound) -> requestCallback.apply(adaptRequest(method, uri, request, outbound)))
@@ -156,6 +156,18 @@ public class ReactorClientHttpConnector implements ClientHttpConnector, SmartLif
 				});
 	}
 
+	private static HttpClient.RequestSender setUri(HttpClient.RequestSender requestSender, URI uri) {
+		if (uri.isAbsolute()) {
+			try {
+				return requestSender.uri(uri);
+			}
+			catch (Exception ex) {
+				// Fall back on passing it in as a String
+			}
+		}
+		return requestSender.uri(uri.toString());
+	}
+
 	private ReactorClientHttpRequest adaptRequest(HttpMethod method, URI uri, HttpClientRequest request,
 			NettyOutbound nettyOutbound) {
 
diff --git a/spring-web/src/main/java/org/springframework/http/converter/StringHttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/StringHttpMessageConverter.java
index 5a408d87497..8b8793e277e 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/StringHttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/StringHttpMessageConverter.java
@@ -93,11 +93,7 @@ public class StringHttpMessageConverter extends AbstractHttpMessageConverter<Str
 	@Override
 	protected String readInternal(Class<? extends String> clazz, HttpInputMessage inputMessage) throws IOException {
 		Charset charset = getContentTypeCharset(inputMessage.getHeaders().getContentType());
-		long length = inputMessage.getHeaders().getContentLength();
-		byte[] bytes = (length >= 0 && length <= Integer.MAX_VALUE ?
-				inputMessage.getBody().readNBytes((int) length) :
-				inputMessage.getBody().readAllBytes());
-		return new String(bytes, charset);
+		return StreamUtils.copyToString(inputMessage.getBody(), charset);
 	}
 
 	@Override
diff --git a/spring-web/src/main/java/org/springframework/web/client/UnknownContentTypeException.java b/spring-web/src/main/java/org/springframework/web/client/UnknownContentTypeException.java
index cfbd27d68bd..a6724f9f851 100644
--- a/spring-web/src/main/java/org/springframework/web/client/UnknownContentTypeException.java
+++ b/spring-web/src/main/java/org/springframework/web/client/UnknownContentTypeException.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -36,8 +36,8 @@ public class UnknownContentTypeException extends RestClientException {
 
 	private static final long serialVersionUID = 2759516676367274084L;
 
-	@SuppressWarnings("serial")
-	private final Type targetType;
+
+	private transient final Type targetType;
 
 	private final MediaType contentType;