springmvc 3.3 json中文乱码

spring-mvc.xml 

<!-- json 乱码 -->
 <mvc:annotation-driven>
  <mvc:message-converters register-defaults="true">
   <bean class="com.*.*.util.UTF8StringHttpMessageConverter"/>
  </mvc:message-converters>
 </mvc:annotation-driven>

public class UTF8StringHttpMessageConverter extends
		AbstractHttpMessageConverter<String> {
	public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
	private final List<Charset> availableCharsets;

	public UTF8StringHttpMessageConverter() {
		this(DEFAULT_CHARSET);
	}

	public UTF8StringHttpMessageConverter(Charset defaultCharset) {
		super(new MediaType("text", "plain", defaultCharset), MediaType.ALL);
		this.availableCharsets = new ArrayList<Charset>(Charset
				.availableCharsets().values());
	}

	@Override
	protected boolean supports(Class<?> clazz) {
		return String.class.equals(clazz);
	}

	@Override
	protected String readInternal(Class<? extends String> clazz,
			HttpInputMessage inputMessage) throws IOException,
			HttpMessageNotReadableException {
		MediaType contentType = inputMessage.getHeaders().getContentType();
		Charset charset = contentType.getCharSet() != null ? contentType
				.getCharSet() : DEFAULT_CHARSET;
		return FileCopyUtils.copyToString(new InputStreamReader(inputMessage
				.getBody(), charset));
	}

	@Override
	protected void writeInternal(String t, HttpOutputMessage outputMessage)
			throws IOException, HttpMessageNotWritableException {
		MediaType contentType = outputMessage.getHeaders().getContentType();
		Charset charset = contentType.getCharSet() != null ? contentType
				.getCharSet() : DEFAULT_CHARSET;
		FileCopyUtils.copy(t, new OutputStreamWriter(outputMessage.getBody(),

		charset));
	}

	protected List<Charset> getAcceptedCharsets() {
		return this.availableCharsets;
	}

	@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) {
				throw new InternalError(ex.getMessage());
			}
		} else {
			return null;
		}
	}
}