org.springframework.http.converter.ResourceHttpMessageConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2015 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.http.converter;
import java.io.IOException;
import java.io.InputStream;
import javax.activation.FileTypeMap;
import javax.activation.MimetypesFileTypeMap;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.InputStreamResource;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.util.ClassUtils;
import org.springframework.util.StreamUtils;
import org.springframework.util.StringUtils;
/**
* Implementation of {@link HttpMessageConverter} that can read and write {@link Resource Resources}.
*
* By default, this converter can read all media types. The Java Activation Framework (JAF) -
* if available - is used to determine the {@code Content-Type} of written resources.
* If JAF is not available, {@code application/octet-stream} is used.
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @author Kazuki Shimizu
* @since 3.0.2
*/
public class ResourceHttpMessageConverter extends AbstractHttpMessageConverter {
private static final boolean jafPresent = ClassUtils.isPresent(
"javax.activation.FileTypeMap", ResourceHttpMessageConverter.class.getClassLoader());
public ResourceHttpMessageConverter() {
super(MediaType.ALL);
}
@Override
protected boolean supports(Class clazz) {
return Resource.class.isAssignableFrom(clazz);
}
@Override
protected Resource readInternal(Class clazz, HttpInputMessage inputMessage)
throws IOException, HttpMessageNotReadableException {
if (InputStreamResource.class == clazz){
return new InputStreamResource(inputMessage.getBody());
}
else if (clazz.isAssignableFrom(ByteArrayResource.class)) {
byte[] body = StreamUtils.copyToByteArray(inputMessage.getBody());
return new ByteArrayResource(body);
}
else {
throw new IllegalStateException("Unsupported resource class: " + clazz);
}
}
@Override
protected MediaType getDefaultContentType(Resource resource) {
if (jafPresent) {
return ActivationMediaTypeFactory.getMediaType(resource);
}
else {
return MediaType.APPLICATION_OCTET_STREAM;
}
}
@Override
protected Long getContentLength(Resource resource, MediaType contentType) throws IOException {
// Don't try to determine contentLength on InputStreamResource - cannot be read afterwards...
// Note: custom InputStreamResource subclasses could provide a pre-calculated content length!
return (InputStreamResource.class == resource.getClass() ? null : resource.contentLength());
}
@Override
protected void writeInternal(Resource resource, HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
InputStream in = resource.getInputStream();
try {
StreamUtils.copy(in, outputMessage.getBody());
}
finally {
try {
in.close();
}
catch (IOException ex) {
}
}
outputMessage.getBody().flush();
}
/**
* Inner class to avoid a hard-coded JAF dependency.
*/
private static class ActivationMediaTypeFactory {
private static final FileTypeMap fileTypeMap;
static {
fileTypeMap = loadFileTypeMapFromContextSupportModule();
}
private static FileTypeMap loadFileTypeMapFromContextSupportModule() {
// See if we can find the extended mime.types from the context-support module...
Resource mappingLocation = new ClassPathResource("org/springframework/mail/javamail/mime.types");
if (mappingLocation.exists()) {
InputStream inputStream = null;
try {
inputStream = mappingLocation.getInputStream();
return new MimetypesFileTypeMap(inputStream);
}
catch (IOException ex) {
// ignore
}
finally {
if (inputStream != null) {
try {
inputStream.close();
}
catch (IOException ex) {
// ignore
}
}
}
}
return FileTypeMap.getDefaultFileTypeMap();
}
public static MediaType getMediaType(Resource resource) {
String filename = resource.getFilename();
if (filename != null) {
String mediaType = fileTypeMap.getContentType(filename);
if (StringUtils.hasText(mediaType)) {
return MediaType.parseMediaType(mediaType);
}
}
return null;
}
}
}