Respect MimeType charset in Jackson codecs

Before this commit, Jackson2CodecSupport and subclasses
did not check media type encoding in the supportsMimeType
method (called from canEncode/canDecode).
As a result, the encoder reported that it can write
(for instance) "application/json;charset=ISO-8859-1", but in practice
wrote the default charset (UTF-8).

This commit fixes that bug.

Closes: gh-25076

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

@@ -18,13 +18,18 @@ package org.springframework.http.codec.json;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Type;
+import java.nio.charset.Charset;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 import com.fasterxml.jackson.annotation.JsonView;
+import com.fasterxml.jackson.core.JsonEncoding;
 import com.fasterxml.jackson.databind.JavaType;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.type.TypeFactory;
@@ -75,6 +80,9 @@ public abstract class Jackson2CodecSupport {
 					new MimeType("application", "json"),
 					new MimeType("application", "*+json")));
 
+	private static final Map<String, JsonEncoding> ENCODINGS = jsonEncodings();
+
+
 
 	protected final Log logger = HttpLogging.forLogName(getClass());
 
@@ -107,7 +115,17 @@ public abstract class Jackson2CodecSupport {
 
 
 	protected boolean supportsMimeType(@Nullable MimeType mimeType) {
-		return (mimeType == null || this.mimeTypes.stream().anyMatch(m -> m.isCompatibleWith(mimeType)));
+		if (mimeType == null) {
+			return true;
+		}
+		else if (this.mimeTypes.stream().noneMatch(m -> m.isCompatibleWith(mimeType))) {
+			return false;
+		}
+		else if (mimeType.getCharset() != null) {
+			Charset charset = mimeType.getCharset();
+			return ENCODINGS.containsKey(charset.name());
+		}
+		return true;
 	}
 
 	protected JavaType getJavaType(Type type, @Nullable Class<?> contextClass) {
@@ -145,4 +163,10 @@ public abstract class Jackson2CodecSupport {
 	@Nullable
 	protected abstract <A extends Annotation> A getAnnotation(MethodParameter parameter, Class<A> annotType);
 
+	private static Map<String, JsonEncoding> jsonEncodings() {
+		return EnumSet.allOf(JsonEncoding.class).stream()
+				.collect(Collectors.toMap(JsonEncoding::getJavaName, Function.identity()));
+	}
+
+
 }

spring-web/src/test/java/org/springframework/http/codec/cbor/Jackson2CborDecoderTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.http.codec.cbor;
 
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
 
@@ -27,13 +28,13 @@ import reactor.core.publisher.Flux;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.testfixture.codec.AbstractDecoderTests;
+import org.springframework.http.MediaType;
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
 import org.springframework.util.MimeType;
 import org.springframework.web.testfixture.xml.Pojo;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.springframework.core.ResolvableType.forClass;
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 
 /**
@@ -58,11 +59,16 @@ public class Jackson2CborDecoderTests extends AbstractDecoderTests<Jackson2CborD
 	@Override
 	@Test
 	public void canDecode() {
-		assertThat(decoder.canDecode(forClass(Pojo.class), CBOR_MIME_TYPE)).isTrue();
-		assertThat(decoder.canDecode(forClass(Pojo.class), null)).isTrue();
+		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), CBOR_MIME_TYPE)).isTrue();
+		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), null)).isTrue();
 
-		assertThat(decoder.canDecode(forClass(String.class), null)).isFalse();
-		assertThat(decoder.canDecode(forClass(Pojo.class), APPLICATION_JSON)).isFalse();
+		assertThat(decoder.canDecode(ResolvableType.forClass(String.class), null)).isFalse();
+		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), APPLICATION_JSON)).isFalse();
+
+		assertThat(this.decoder.canDecode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "cbor", StandardCharsets.UTF_8))).isTrue();
+		assertThat(this.decoder.canDecode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "cbor", StandardCharsets.ISO_8859_1))).isFalse();
 	}
 
 	@Override

spring-web/src/test/java/org/springframework/http/codec/cbor/Jackson2CborEncoderTests.java

@@ -18,6 +18,7 @@ package org.springframework.http.codec.cbor;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.nio.charset.StandardCharsets;
 import java.util.function.Consumer;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
@@ -28,6 +29,7 @@ import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.testfixture.io.buffer.AbstractLeakCheckingTests;
 import org.springframework.core.testfixture.io.buffer.DataBufferTestUtils;
+import org.springframework.http.MediaType;
 import org.springframework.http.codec.ServerSentEvent;
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
 import org.springframework.util.MimeType;
@@ -73,6 +75,12 @@ public class Jackson2CborEncoderTests extends AbstractLeakCheckingTests {
 
 		// SPR-15464
 		assertThat(this.encoder.canEncode(ResolvableType.NONE, null)).isTrue();
+
+
+		assertThat(this.encoder.canEncode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "cbor", StandardCharsets.UTF_8))).isTrue();
+		assertThat(this.encoder.canEncode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "cbor", StandardCharsets.ISO_8859_1))).isFalse();
 	}
 
 	@Test

spring-web/src/test/java/org/springframework/http/codec/json/Jackson2JsonDecoderTests.java

@@ -85,6 +85,10 @@ public class Jackson2JsonDecoderTests extends AbstractDecoderTests<Jackson2JsonD
 
 		assertThat(decoder.canDecode(forClass(String.class), null)).isFalse();
 		assertThat(decoder.canDecode(forClass(Pojo.class), APPLICATION_XML)).isFalse();
+		assertThat(this.decoder.canDecode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "json", StandardCharsets.UTF_8))).isTrue();
+		assertThat(this.decoder.canDecode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "json", StandardCharsets.ISO_8859_1))).isFalse();
 	}
 
 	@Test  // SPR-15866

spring-web/src/test/java/org/springframework/http/codec/json/Jackson2JsonEncoderTests.java

@@ -69,11 +69,18 @@ public class Jackson2JsonEncoderTests extends AbstractEncoderTests<Jackson2JsonE
 		assertThat(this.encoder.canEncode(pojoType, APPLICATION_STREAM_JSON)).isTrue();
 		assertThat(this.encoder.canEncode(pojoType, null)).isTrue();
 
+		assertThat(this.encoder.canEncode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "json", StandardCharsets.UTF_8))).isTrue();
+		assertThat(this.encoder.canEncode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "json", StandardCharsets.ISO_8859_1))).isFalse();
+
 		// SPR-15464
 		assertThat(this.encoder.canEncode(ResolvableType.NONE, null)).isTrue();
 
 		// SPR-15910
 		assertThat(this.encoder.canEncode(ResolvableType.forClass(Object.class), APPLICATION_OCTET_STREAM)).isFalse();
+
+
 	}
 
 	@Override

spring-web/src/test/java/org/springframework/http/codec/json/Jackson2SmileDecoderTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.http.codec.json;
 
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
 
@@ -27,12 +28,12 @@ import reactor.core.publisher.Flux;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.testfixture.codec.AbstractDecoderTests;
+import org.springframework.http.MediaType;
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
 import org.springframework.util.MimeType;
 import org.springframework.web.testfixture.xml.Pojo;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.springframework.core.ResolvableType.forClass;
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 
 /**
@@ -58,12 +59,18 @@ public class Jackson2SmileDecoderTests extends AbstractDecoderTests<Jackson2Smil
 	@Override
 	@Test
 	public void canDecode() {
-		assertThat(decoder.canDecode(forClass(Pojo.class), SMILE_MIME_TYPE)).isTrue();
-		assertThat(decoder.canDecode(forClass(Pojo.class), STREAM_SMILE_MIME_TYPE)).isTrue();
-		assertThat(decoder.canDecode(forClass(Pojo.class), null)).isTrue();
+		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), SMILE_MIME_TYPE)).isTrue();
+		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), STREAM_SMILE_MIME_TYPE)).isTrue();
+		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), null)).isTrue();
+
+		assertThat(decoder.canDecode(ResolvableType.forClass(String.class), null)).isFalse();
+		assertThat(decoder.canDecode(ResolvableType.forClass(Pojo.class), APPLICATION_JSON)).isFalse();
+
+		assertThat(this.decoder.canDecode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "x-jackson-smile", StandardCharsets.UTF_8))).isTrue();
+		assertThat(this.decoder.canDecode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "x-jackson-smile", StandardCharsets.ISO_8859_1))).isFalse();
 
-		assertThat(decoder.canDecode(forClass(String.class), null)).isFalse();
-		assertThat(decoder.canDecode(forClass(Pojo.class), APPLICATION_JSON)).isFalse();
 	}
 
 	@Override

spring-web/src/test/java/org/springframework/http/codec/json/Jackson2SmileEncoderTests.java

@@ -18,6 +18,7 @@ package org.springframework.http.codec.json;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
 
@@ -32,6 +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.testfixture.codec.AbstractEncoderTests;
+import org.springframework.http.MediaType;
 import org.springframework.http.codec.ServerSentEvent;
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
 import org.springframework.util.MimeType;
@@ -68,6 +70,11 @@ public class Jackson2SmileEncoderTests extends AbstractEncoderTests<Jackson2Smil
 		assertThat(this.encoder.canEncode(pojoType, STREAM_SMILE_MIME_TYPE)).isTrue();
 		assertThat(this.encoder.canEncode(pojoType, null)).isTrue();
 
+		assertThat(this.encoder.canEncode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "x-jackson-smile", StandardCharsets.UTF_8))).isTrue();
+		assertThat(this.encoder.canEncode(ResolvableType.forClass(Pojo.class),
+				new MediaType("application", "x-jackson-smile", StandardCharsets.ISO_8859_1))).isFalse();
+
 		// SPR-15464
 		assertThat(this.encoder.canEncode(ResolvableType.NONE, null)).isTrue();
 	}