/*
* Copyright 2002-2019 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
*
* https://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.messaging.converter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.lang.reflect.Type;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.concurrent.atomic.AtomicReference;
import com.fasterxml.jackson.annotation.JsonView;
import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.springframework.core.GenericTypeResolver;
import org.springframework.core.MethodParameter;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.util.Assert;
import org.springframework.util.MimeType;
/**
* A Jackson 2 based {@link MessageConverter} implementation.
*
* <p>It customizes Jackson's default properties with the following ones:
* <ul>
* <li>{@link MapperFeature#DEFAULT_VIEW_INCLUSION} is disabled</li>
* <li>{@link DeserializationFeature#FAIL_ON_UNKNOWN_PROPERTIES} is disabled</li>
* </ul>
*
* <p>Compatible with Jackson 2.9 and higher, as of Spring 5.1.
*
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @author Sebastien Deleuze
* @since 4.0
*/
public class MappingJackson2MessageConverter extends AbstractMessageConverter {
private ObjectMapper objectMapper;
@Nullable
private Boolean prettyPrint;
/**
* Construct a {@code MappingJackson2MessageConverter} supporting
* the {@code application/json} MIME type with {@code UTF-8} character set.
*/
public MappingJackson2MessageConverter() {
super(new MimeType("application", "json"));
this.objectMapper = initObjectMapper();
}
/**
* Construct a {@code MappingJackson2MessageConverter} supporting
* one or more custom MIME types.
* @param supportedMimeTypes the supported MIME types
* @since 4.1.5
*/
public MappingJackson2MessageConverter(MimeType... supportedMimeTypes) {
super(Arrays.asList(supportedMimeTypes));
this.objectMapper = initObjectMapper();
}
private ObjectMapper initObjectMapper() {
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(MapperFeature.DEFAULT_VIEW_INCLUSION, false);
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
return objectMapper;
}
/**
* Set the {@code ObjectMapper} for this converter.
* If not set, a default {@link ObjectMapper#ObjectMapper() ObjectMapper} is used.
* <p>Setting a custom-configured {@code ObjectMapper} is one way to take further
* control of the JSON serialization process. For example, an extended
* {@link com.fasterxml.jackson.databind.ser.SerializerFactory} can be
* configured that provides custom serializers for specific types. The other
* option for refining the serialization process is to use Jackson's provided
* annotations on the types to be serialized, in which case a custom-configured
* ObjectMapper is unnecessary.
*/
public void setObjectMapper(ObjectMapper objectMapper) {
Assert.notNull(objectMapper, "ObjectMapper must not be null");
this.objectMapper = objectMapper;
configurePrettyPrint();
}
/**
* Return the underlying {@code ObjectMapper} for this converter.
*/
public ObjectMapper getObjectMapper() {
return this.objectMapper;
}
/**
* Whether to use the {@link DefaultPrettyPrinter} when writing JSON.
* This is a shortcut for setting up an {@code ObjectMapper} as follows:
* <pre class="code">
* ObjectMapper mapper = new ObjectMapper();
* mapper.configure(SerializationFeature.INDENT_OUTPUT, true);
* converter.setObjectMapper(mapper);
* </pre>
*/
public void setPrettyPrint(boolean prettyPrint) {
this.prettyPrint = prettyPrint;
configurePrettyPrint();
}
private void configurePrettyPrint() {
if (this.prettyPrint != null) {
this.objectMapper.configure(SerializationFeature.INDENT_OUTPUT, this.prettyPrint);
}
}
@Override
protected boolean canConvertFrom(Message<?> message, @Nullable Class<?> targetClass) {
if (targetClass == null || !supportsMimeType(message.getHeaders())) {
return false;
}
JavaType javaType = this.objectMapper.constructType(targetClass);
AtomicReference<Throwable> causeRef = new AtomicReference<>();
if (this.objectMapper.canDeserialize(javaType, causeRef)) {
return true;
}
logWarningIfNecessary(javaType, causeRef.get());
return false;
}
@Override
protected boolean canConvertTo(Object payload, @Nullable MessageHeaders headers) {
if (!supportsMimeType(headers)) {
return false;
}
AtomicReference<Throwable> causeRef = new AtomicReference<>();
if (this.objectMapper.canSerialize(payload.getClass(), causeRef)) {
return true;
}
logWarningIfNecessary(payload.getClass(), causeRef.get());
return false;
}
/**
* Determine whether to log the given exception coming from a
* {@link ObjectMapper#canDeserialize} / {@link ObjectMapper#canSerialize} check.
* @param type the class that Jackson tested for (de-)serializability
* @param cause the Jackson-thrown exception to evaluate
* (typically a {@link JsonMappingException})
* @since 4.3
*/
protected void logWarningIfNecessary(Type type, @Nullable Throwable cause) {
if (cause == null) {
return;
}
// Do not log warning for serializer not found (note: different message wording on Jackson 2.9)
boolean debugLevel = (cause instanceof JsonMappingException && cause.getMessage().startsWith("Cannot find"));
if (debugLevel ? logger.isDebugEnabled() : logger.isWarnEnabled()) {
String msg = "Failed to evaluate Jackson " + (type instanceof JavaType ? "de" : "") +
"serialization for type [" + type + "]";
if (debugLevel) {
logger.debug(msg, cause);
}
else if (logger.isDebugEnabled()) {
logger.warn(msg, cause);
}
else {
logger.warn(msg + ": " + cause);
}
}
}
@Override
protected boolean supports(Class<?> clazz) {
// should not be called, since we override canConvertFrom/canConvertTo instead
throw new UnsupportedOperationException();
}
@Override
@Nullable
protected Object convertFromInternal(Message<?> message, Class<?> targetClass, @Nullable Object conversionHint) {
JavaType javaType = getJavaType(targetClass, conversionHint);
Object payload = message.getPayload();
Class<?> view = getSerializationView(conversionHint);
// Note: in the view case, calling withType instead of forType for compatibility with Jackson <2.5
try {
if (payload instanceof byte[]) {
if (view != null) {
return this.objectMapper.readerWithView(view).forType(javaType).readValue((byte[]) payload);
}
else {
return this.objectMapper.readValue((byte[]) payload, javaType);
}
}
else if (targetClass.isInstance(payload)) {
return payload;
}
else {
if (view != null) {
return this.objectMapper.readerWithView(view).forType(javaType).readValue(payload.toString());
}
else {
return this.objectMapper.readValue(payload.toString(), javaType);
}
}
}
catch (IOException ex) {
throw new MessageConversionException(message, "Could not read JSON: " + ex.getMessage(), ex);
}
}
private JavaType getJavaType(Class<?> targetClass, @Nullable Object conversionHint) {
if (conversionHint instanceof MethodParameter) {
MethodParameter param = (MethodParameter) conversionHint;
param = param.nestedIfOptional();
if (Message.class.isAssignableFrom(param.getParameterType())) {
param = param.nested();
}
Type genericParameterType = param.getNestedGenericParameterType();
Class<?> contextClass = param.getContainingClass();
Type type = GenericTypeResolver.resolveType(genericParameterType, contextClass);
return this.objectMapper.getTypeFactory().constructType(type);
}
return this.objectMapper.constructType(targetClass);
}
@Override
@Nullable
protected Object convertToInternal(Object payload, @Nullable MessageHeaders headers,
@Nullable Object conversionHint) {
try {
Class<?> view = getSerializationView(conversionHint);
if (byte[].class == getSerializedPayloadClass()) {
ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
JsonEncoding encoding = getJsonEncoding(getMimeType(headers));
JsonGenerator generator = this.objectMapper.getFactory().createGenerator(out, encoding);
if (view != null) {
this.objectMapper.writerWithView(view).writeValue(generator, payload);
}
else {
this.objectMapper.writeValue(generator, payload);
}
payload = out.toByteArray();
}
else {
Writer writer = new StringWriter();
if (view != null) {
this.objectMapper.writerWithView(view).writeValue(writer, payload);
}
else {
this.objectMapper.writeValue(writer, payload);
}
payload = writer.toString();
}
}
catch (IOException ex) {
throw new MessageConversionException("Could not write JSON: " + ex.getMessage(), ex);
}
return payload;
}
/**
* Determine a Jackson serialization view based on the given conversion hint.
* @param conversionHint the conversion hint Object as passed into the
* converter for the current conversion attempt
* @return the serialization view class, or {@code null} if none
* @since 4.2
*/
@Nullable
protected Class<?> getSerializationView(@Nullable Object conversionHint) {
if (conversionHint instanceof MethodParameter) {
MethodParameter param = (MethodParameter) conversionHint;
JsonView annotation = (param.getParameterIndex() >= 0 ?
param.getParameterAnnotation(JsonView.class) : param.getMethodAnnotation(JsonView.class));
if (annotation != null) {
return extractViewClass(annotation, conversionHint);
}
}
else if (conversionHint instanceof JsonView) {
return extractViewClass((JsonView) conversionHint, conversionHint);
}
else if (conversionHint instanceof Class) {
return (Class<?>) conversionHint;
}
// No JSON view specified...
return null;
}
private Class<?> extractViewClass(JsonView annotation, Object conversionHint) {
Class<?>[] classes = annotation.value();
if (classes.length != 1) {
throw new IllegalArgumentException(
"@JsonView only supported for handler methods with exactly 1 class argument: " + conversionHint);
}
return classes[0];
}
/**
* Determine the JSON encoding to use for the given content type.
* @param contentType the MIME type from the MessageHeaders, if any
* @return the JSON encoding to use (never {@code null})
*/
protected JsonEncoding getJsonEncoding(@Nullable MimeType contentType) {
if (contentType != null && (contentType.getCharset() != null)) {
Charset charset = contentType.getCharset();
for (JsonEncoding encoding : JsonEncoding.values()) {
if (charset.name().equals(encoding.getJavaName())) {
return encoding;
}
}
}
return JsonEncoding.UTF8;
}
}
