/**
 * @author xichao.dong   
 * @email 406592176@qq.com
 * @date 2014-8-15 上午8:50:38 
 * @company (开发公司)    珠海市冰川软件有限公司
 * @copyright (版权)    本文件归属珠海市冰川软件有限公司所有
 * @version V1.0
 * @modify (修改) : 2014-8-15 上午8:50:38  xichao.dong 
 * @Review (审核人) ：xichao.dong 
 */
package com.glacier.basic.util;

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;

/**
 * @ClassName: UTF8StringHttpMessageConverter 
 * @Description: TODO(修正springmvc的@ResponseBody中文乱码问题) 
 * @author xichao.dong	
 * @email 406592176@qq.com
 * @date 2014-8-15 上午11:16:55
 */
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", "html", DEFAULT_CHARSET));
		this.availableCharsets = new ArrayList<Charset>(Charset
				.availableCharsets().values());
	}

	public void setWriteAcceptCharset(boolean writeAcceptCharset) {
		this.writeAcceptCharset = writeAcceptCharset;
	}

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

	@Override
	protected String readInternal(@SuppressWarnings("rawtypes") 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) {
			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));
	}

	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;
		}
	}
}