spring mvc3.1 @ResponseBody注解生成大量Accept-Charset

Spring3 MVC使用@ResponseBody后会产生很大的响应头(Accept-Charset会达到4K+)，原因在于默认情况下StringHttpMessageConverter.writeInternal()会将所有可用字符集回写到response响应头中：问题来了


解决方式：

一般我们都会重写springs mvc的HttpMessageConverter，改为utf-8编码：

package com.goldpalm.core.spring.mvc;

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.http.converter.AbstractHttpMessageConverter;
import org.springframework.util.FileCopyUtils;

/**
* 重写SpringMVC的字符串转换器，使用UTF-8编码
* @since 2012-7-5 下午2:28:19
* @author Jesse Lu
*/
public class UTF8StringHttpMessageConverter extends AbstractHttpMessageConverter<String> {

public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");

private final List<Charset> availableCharsets;

private boolean writeAcceptCharset = true;

public UTF8StringHttpMessageConverter() {
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);
}

@SuppressWarnings("rawtypes")
@Override
protected String readInternal(Class clazz, HttpInputMessage inputMessage) throws IOException {
Charset charset = getContentTypeCharset(inputMessage.getHeaders().getContentType());
return FileCopyUtils.copyToString(new InputStreamReader(inputMessage.getBody(), charset));
}

@Override
protected Long getContentLength(String s, MediaType contentType) {
Charset charset = getContentTypeCharset(contentType);
try {
return (long) s.getBytes(charset.name()).length;
} catch (UnsupportedEncodingException ex) {
// should not occur
throw new InternalError(ex.getMessage());
}
}

@Override
protected void writeInternal(String s, HttpOutputMessage outputMessage) throws IOException {
if (writeAcceptCharset) {
outputMessage.getHeaders().setAcceptCharset(getAcceptedCharsets());
}
Charset charset = getContentTypeCharset(outputMessage.getHeaders().getContentType());
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;
}

private Charset getContentTypeCharset(MediaType contentType) {
if (contentType != null && contentType.getCharSet() != null) {
return contentType.getCharSet();
} else {
return DEFAULT_CHARSET;
}
}

}


在xm中配置：注意红色圈起来的配置



<mvc:annotation-driven>
<mvc:message-converters>
<bean class="com.goldpalm.core.spring.mvc.UTF8StringHttpMessageConverter">
<property name="writeAcceptCharset" value="false" />
</bean>
</mvc:message-converters>
</mvc:annotation-driven>