org.springframework.messaging.converter.MappingJackson2MessageConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2014 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.messaging.converter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.nio.charset.Charset;
import java.util.concurrent.atomic.AtomicReference;
import com.fasterxml.jackson.core.JsonEncoding;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.MimeType;
/**
* A Jackson 2 based {@link MessageConverter} implementation.
*
* Compatible with Jackson 2.1 and higher.
*
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @since 4.0
*/
public class MappingJackson2MessageConverter extends AbstractMessageConverter {
// Check for Jackson 2.3's overloaded canDeserialize/canSerialize variants with cause reference
private static final boolean jackson23Available =
ClassUtils.hasMethod(ObjectMapper.class, "canDeserialize", JavaType.class, AtomicReference.class);
private ObjectMapper objectMapper = new ObjectMapper();
private Boolean prettyPrint;
public MappingJackson2MessageConverter() {
super(new MimeType("application", "json", Charset.forName("UTF-8")));
}
/**
* Set the {@code ObjectMapper} for this converter.
* If not set, a default {@link ObjectMapper#ObjectMapper() ObjectMapper} is used.
*
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:
*
* ObjectMapper mapper = new ObjectMapper();
* mapper.configure(SerializationFeature.INDENT_OUTPUT, true);
* converter.setObjectMapper(mapper);
*
*/
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, Class targetClass) {
if (targetClass == null) {
return false;
}
JavaType javaType = this.objectMapper.constructType(targetClass);
if (!jackson23Available || !logger.isWarnEnabled()) {
return (this.objectMapper.canDeserialize(javaType) && supportsMimeType(message.getHeaders()));
}
AtomicReference causeRef = new AtomicReference();
if (this.objectMapper.canDeserialize(javaType, causeRef) && supportsMimeType(message.getHeaders())) {
return true;
}
Throwable cause = causeRef.get();
if (cause != null) {
String msg = "Failed to evaluate deserialization for type " + javaType;
if (logger.isDebugEnabled()) {
logger.warn(msg, cause);
}
else {
logger.warn(msg + ": " + cause);
}
}
return false;
}
@Override
protected boolean canConvertTo(Object payload, MessageHeaders headers) {
if (!jackson23Available || !logger.isWarnEnabled()) {
return (this.objectMapper.canSerialize(payload.getClass()) && supportsMimeType(headers));
}
AtomicReference causeRef = new AtomicReference();
if (this.objectMapper.canSerialize(payload.getClass(), causeRef) && supportsMimeType(headers)) {
return true;
}
Throwable cause = causeRef.get();
if (cause != null) {
String msg = "Failed to evaluate serialization for type [" + payload.getClass() + "]";
if (logger.isDebugEnabled()) {
logger.warn(msg, cause);
}
else {
logger.warn(msg + ": " + cause);
}
}
return false;
}
@Override
protected boolean supports(Class clazz) {
// should not be called, since we override canConvertFrom/canConvertTo instead
throw new UnsupportedOperationException();
}
@Override
public Object convertFromInternal(Message message, Class targetClass) {
JavaType javaType = this.objectMapper.constructType(targetClass);
Object payload = message.getPayload();
try {
if (payload instanceof byte[]) {
return this.objectMapper.readValue((byte[]) payload, javaType);
}
else {
return this.objectMapper.readValue((String) payload, javaType);
}
}
catch (IOException ex) {
throw new MessageConversionException(message, "Could not read JSON: " + ex.getMessage(), ex);
}
}
@Override
public Object convertToInternal(Object payload, MessageHeaders headers) {
try {
if (byte[].class.equals(getSerializedPayloadClass())) {
ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
JsonEncoding encoding = getJsonEncoding(getMimeType(headers));
JsonGenerator generator = this.objectMapper.getFactory().createGenerator(out, encoding);
this.objectMapper.writeValue(generator, payload);
payload = out.toByteArray();
}
else {
Writer writer = new StringWriter();
this.objectMapper.writeValue(writer, payload);
payload = writer.toString();
}
}
catch (IOException ex) {
throw new MessageConversionException("Could not write JSON: " + ex.getMessage(), ex);
}
return payload;
}
/**
* 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(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;
}
}