/*
* Copyright 2002-2010 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.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.util.FileCopyUtils;
/**
* Implementation of {@link HttpMessageConverter} that can read and write strings.
*
* <p>By default, this converter supports all media types (<code>*/*</code>), and writes with a {@code
* Content-Type} of {@code text/plain}. This can be overridden by setting the {@link
* #setSupportedMediaTypes(java.util.List) supportedMediaTypes} property.
*
* @author Arjen Poutsma
* @since 3.0
*/
public class StringHttpMessageConverter extends AbstractHttpMessageConverter<String> {
public static final Charset DEFAULT_CHARSET = Charset.forName("ISO-8859-1");
private final List<Charset> availableCharsets;
private boolean writeAcceptCharset = true;
public StringHttpMessageConverter() {
super(new MediaType("text", "plain", DEFAULT_CHARSET), MediaType.ALL);
this.availableCharsets = new ArrayList<Charset>(Charset.availableCharsets().values());
}
/**
* Indicates whether the {@code Accept-Charset} should be written to any outgoing request.
* <p>Default is {@code true}.
*/
public void setWriteAcceptCharset(boolean writeAcceptCharset) {
this.writeAcceptCharset = writeAcceptCharset;
}
@Override
public boolean supports(Class<?> clazz) {
return String.class.equals(clazz);
}
@Override
protected String readInternal(Class clazz, HttpInputMessage inputMessage) throws IOException {
MediaType contentType = inputMessage.getHeaders().getContentType();
Charset charset = contentType.getCharSet() != null ? contentType.getCharSet() : DEFAULT_CHARSET;
return FileCopyUtils.copyToString(new InputStreamReader(inputMessage.getBody(), charset));
}
@Override
protected Long getContentLength(String s, MediaType contentType) {
if (contentType != null && contentType.getCharSet() != null) {
Charset charset = contentType.getCharSet();
try {
return (long) s.getBytes(charset.name()).length;
}
catch (UnsupportedEncodingException ex) {
// should not occur
throw new InternalError(ex.getMessage());
}
}
else {
return null;
}
}
@Override
protected void writeInternal(String s, HttpOutputMessage outputMessage) throws IOException {
if (writeAcceptCharset) {
outputMessage.getHeaders().setAcceptCharset(getAcceptedCharsets());
}
MediaType contentType = outputMessage.getHeaders().getContentType();
Charset charset = contentType.getCharSet() != null ? contentType.getCharSet() : DEFAULT_CHARSET;
FileCopyUtils.copy(s, new OutputStreamWriter(outputMessage.getBody(), charset));
}
/**
* Return the list of supported {@link Charset}.
*
* <p>By default, returns {@link Charset#availableCharsets()}. Can be overridden in subclasses.
*
* @return the list of accepted charsets
*/
protected List<Charset> getAcceptedCharsets() {
return this.availableCharsets;
}
}
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