org.springframework.messaging.converter.MarshallingMessageConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2020 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.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import org.springframework.beans.TypeMismatchException;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.oxm.Marshaller;
import org.springframework.oxm.Unmarshaller;
import org.springframework.util.Assert;
import org.springframework.util.MimeType;
/**
* Implementation of {@link MessageConverter} that can read and write XML using Spring's
* {@link Marshaller} and {@link Unmarshaller} abstractions.
*
* This converter requires a {@code Marshaller} and {@code Unmarshaller} before it can
* be used. These can be injected by the {@linkplain #MarshallingMessageConverter(Marshaller)
* constructor} or {@linkplain #setMarshaller(Marshaller) bean properties}.
*
* @author Arjen Poutsma
* @since 4.2
* @see Marshaller
* @see Unmarshaller
*/
public class MarshallingMessageConverter extends AbstractMessageConverter {
@Nullable
private Marshaller marshaller;
@Nullable
private Unmarshaller unmarshaller;
/**
* Default construct allowing for {@link #setMarshaller(Marshaller)} and/or
* {@link #setUnmarshaller(Unmarshaller)} to be invoked separately.
*/
public MarshallingMessageConverter() {
this(new MimeType("application", "xml"), new MimeType("text", "xml"),
new MimeType("application", "*+xml"));
}
/**
* Constructor with a given list of MIME types to support.
* @param supportedMimeTypes the MIME types
*/
public MarshallingMessageConverter(MimeType... supportedMimeTypes) {
super(supportedMimeTypes);
}
/**
* Constructor with {@link Marshaller}. If the given {@link Marshaller} also
* implements {@link Unmarshaller}, it is also used for unmarshalling.
*
Note that all {@code Marshaller} implementations in Spring also implement
* {@code Unmarshaller} so that you can safely use this constructor.
* @param marshaller object used as marshaller and unmarshaller
*/
public MarshallingMessageConverter(Marshaller marshaller) {
this();
Assert.notNull(marshaller, "Marshaller must not be null");
this.marshaller = marshaller;
if (marshaller instanceof Unmarshaller) {
this.unmarshaller = (Unmarshaller) marshaller;
}
}
/**
* Set the {@link Marshaller} to be used by this message converter.
*/
public void setMarshaller(@Nullable Marshaller marshaller) {
this.marshaller = marshaller;
}
/**
* Return the configured Marshaller.
*/
@Nullable
public Marshaller getMarshaller() {
return this.marshaller;
}
/**
* Set the {@link Unmarshaller} to be used by this message converter.
*/
public void setUnmarshaller(@Nullable Unmarshaller unmarshaller) {
this.unmarshaller = unmarshaller;
}
/**
* Return the configured unmarshaller.
*/
@Nullable
public Unmarshaller getUnmarshaller() {
return this.unmarshaller;
}
@Override
protected boolean canConvertFrom(Message message, Class targetClass) {
return (supportsMimeType(message.getHeaders()) && this.unmarshaller != null &&
this.unmarshaller.supports(targetClass));
}
@Override
protected boolean canConvertTo(Object payload, @Nullable MessageHeaders headers) {
return (supportsMimeType(headers) && this.marshaller != null &&
this.marshaller.supports(payload.getClass()));
}
@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) {
Assert.notNull(this.unmarshaller, "Property 'unmarshaller' is required");
try {
Source source = getSource(message.getPayload());
Object result = this.unmarshaller.unmarshal(source);
if (!targetClass.isInstance(result)) {
throw new TypeMismatchException(result, targetClass);
}
return result;
}
catch (Exception ex) {
throw new MessageConversionException(message, "Could not unmarshal XML: " + ex.getMessage(), ex);
}
}
private Source getSource(Object payload) {
if (payload instanceof byte[]) {
return new StreamSource(new ByteArrayInputStream((byte[]) payload));
}
else {
return new StreamSource(new StringReader(payload.toString()));
}
}
@Override
@Nullable
protected Object convertToInternal(Object payload, @Nullable MessageHeaders headers,
@Nullable Object conversionHint) {
Assert.notNull(this.marshaller, "Property 'marshaller' is required");
try {
if (byte[].class == getSerializedPayloadClass()) {
ByteArrayOutputStream out = new ByteArrayOutputStream(1024);
Result result = new StreamResult(out);
this.marshaller.marshal(payload, result);
payload = out.toByteArray();
}
else {
Writer writer = new StringWriter(1024);
Result result = new StreamResult(writer);
this.marshaller.marshal(payload, result);
payload = writer.toString();
}
}
catch (Throwable ex) {
throw new MessageConversionException("Could not marshal XML: " + ex.getMessage(), ex);
}
return payload;
}
}