diff --git a/spring-web/src/main/java/org/springframework/http/codec/json/JacksonJsonDecoder.java b/spring-web/src/main/java/org/springframework/http/codec/json/JacksonJsonDecoder.java
index 73cb908d6fe..467bc52a39b 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/json/JacksonJsonDecoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/json/JacksonJsonDecoder.java
@@ -104,9 +104,10 @@ public class JacksonJsonDecoder extends AbstractJacksonDecoder<JsonMapper> {
 		super(mapper, mimeTypes);
 	}
 
+
 	@Override
 	public boolean canDecode(ResolvableType elementType, @Nullable MimeType mimeType) {
-		return super.canDecode(elementType, mimeType) && !CharSequence.class.isAssignableFrom(elementType.toClass());
+		return (super.canDecode(elementType, mimeType) && String.class != elementType.toClass());
 	}
 
 	@Override
diff --git a/spring-web/src/main/java/org/springframework/http/codec/json/JacksonJsonEncoder.java b/spring-web/src/main/java/org/springframework/http/codec/json/JacksonJsonEncoder.java
index e8a14d01b03..10ba18c5860 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/json/JacksonJsonEncoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/json/JacksonJsonEncoder.java
@@ -123,7 +123,7 @@ public class JacksonJsonEncoder extends AbstractJacksonEncoder<JsonMapper> {
 
 	@Override
 	public boolean canEncode(ResolvableType elementType, @Nullable MimeType mimeType) {
-		return super.canEncode(elementType, mimeType) && !String.class.isAssignableFrom(elementType.toClass());
+		return (super.canEncode(elementType, mimeType) && String.class != elementType.toClass());
 	}
 
 	@Override
diff --git a/spring-web/src/main/java/org/springframework/http/codec/xml/JacksonXmlDecoder.java b/spring-web/src/main/java/org/springframework/http/codec/xml/JacksonXmlDecoder.java
index d75e13f692b..6de9cc6e609 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/xml/JacksonXmlDecoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/xml/JacksonXmlDecoder.java
@@ -102,6 +102,11 @@ public class JacksonXmlDecoder extends AbstractJacksonDecoder<XmlMapper> {
 	}
 
 
+	@Override
+	public boolean canDecode(ResolvableType elementType, @Nullable MimeType mimeType) {
+		return (super.canDecode(elementType, mimeType) && String.class != elementType.toClass());
+	}
+
 	@Override
 	public Flux<Object> decode(Publisher<DataBuffer> input, ResolvableType elementType, @Nullable MimeType mimeType,
 			@Nullable Map<String, Object> hints) {
diff --git a/spring-web/src/main/java/org/springframework/http/codec/xml/JacksonXmlEncoder.java b/spring-web/src/main/java/org/springframework/http/codec/xml/JacksonXmlEncoder.java
index a298a7b3d0f..0835ddf574d 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/xml/JacksonXmlEncoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/xml/JacksonXmlEncoder.java
@@ -97,6 +97,11 @@ public class JacksonXmlEncoder extends AbstractJacksonEncoder<XmlMapper> {
 	}
 
 
+	@Override
+	public boolean canEncode(ResolvableType elementType, @Nullable MimeType mimeType) {
+		return (super.canEncode(elementType, mimeType) && String.class != elementType.toClass());
+	}
+
 	@Override
 	public Flux<DataBuffer> encode(Publisher<?> inputStream, DataBufferFactory bufferFactory, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
diff --git a/spring-web/src/test/java/org/springframework/http/codec/json/JacksonJsonEncoderTests.java b/spring-web/src/test/java/org/springframework/http/codec/json/JacksonJsonEncoderTests.java
index bb3b06bd064..6b900fe5dbf 100644
--- a/spring-web/src/test/java/org/springframework/http/codec/json/JacksonJsonEncoderTests.java
+++ b/spring-web/src/test/java/org/springframework/http/codec/json/JacksonJsonEncoderTests.java
@@ -90,6 +90,7 @@ class JacksonJsonEncoderTests extends AbstractEncoderTests<JacksonJsonEncoder> {
 
 		// SPR-15910
 		assertThat(this.encoder.canEncode(ResolvableType.forClass(Object.class), APPLICATION_OCTET_STREAM)).isFalse();
+		assertThat(this.encoder.canEncode(ResolvableType.forClass(String.class), null)).isFalse();
 
 		assertThatThrownBy(() -> this.encoder.canEncode(ResolvableType.forClass(MappingJacksonValue.class), APPLICATION_JSON))
 				.isInstanceOf(UnsupportedOperationException.class);
diff --git a/spring-web/src/test/java/org/springframework/http/codec/xml/JacksonXmlDecoderTests.java b/spring-web/src/test/java/org/springframework/http/codec/xml/JacksonXmlDecoderTests.java
index b9c62214799..c4a77be7d9b 100644
--- a/spring-web/src/test/java/org/springframework/http/codec/xml/JacksonXmlDecoderTests.java
+++ b/spring-web/src/test/java/org/springframework/http/codec/xml/JacksonXmlDecoderTests.java
@@ -59,7 +59,7 @@ class JacksonXmlDecoderTests extends AbstractDecoderTests<JacksonXmlDecoder> {
 		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), MediaType.TEXT_XML)).isTrue();
 		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), new MediaType("application", "soap+xml"))).isTrue();
 		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), null)).isTrue();
-		assertThat(decoder.canDecode(ResolvableType.forClass(String.class), null)).isTrue();
+		assertThat(decoder.canDecode(ResolvableType.forClass(String.class), null)).isFalse();
 		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), MediaType.APPLICATION_JSON)).isFalse();
 	}
 
diff --git a/spring-web/src/test/java/org/springframework/http/codec/xml/JacksonXmlEncoderTests.java b/spring-web/src/test/java/org/springframework/http/codec/xml/JacksonXmlEncoderTests.java
index d7a2d7ba8ca..8d4f552a54d 100644
--- a/spring-web/src/test/java/org/springframework/http/codec/xml/JacksonXmlEncoderTests.java
+++ b/spring-web/src/test/java/org/springframework/http/codec/xml/JacksonXmlEncoderTests.java
@@ -52,7 +52,7 @@ class JacksonXmlEncoderTests extends AbstractLeakCheckingTests {
 		assertThat(this.encoder.canEncode(pojoType, MediaType.TEXT_XML)).isTrue();
 		assertThat(this.encoder.canEncode(pojoType, new MediaType("application", "soap+xml"))).isTrue();
 		assertThat(this.encoder.canEncode(pojoType, null)).isTrue();
-		assertThat(this.encoder.canEncode(ResolvableType.forClass(String.class), null)).isTrue();
+		assertThat(this.encoder.canEncode(ResolvableType.forClass(String.class), null)).isFalse();
 		assertThat(this.encoder.canEncode(ResolvableType.NONE, null)).isTrue();
 		assertThat(this.encoder.canEncode(ResolvableType.forClass(Pojo.class), MediaType.APPLICATION_JSON)).isFalse();
 	}