/**
 * 处理微信请求servlet
 * @author caspar.chen
 * @version 1.0
 * 
 */
public class WeChatServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 随机字符串
		String echostr = request.getParameter("echostr");

		PrintWriter out = null;
		try {
			out = response.getWriter();
			// 通过检验signature对请求进行校验，若校验成功则原样返回echostr，否则接入失败
			if (SignService.checkSignature(request)) {
				out.print(echostr);
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			out.close();
			out = null;
		}
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		try {
			request.setCharacterEncoding("UTF-8");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		response.setCharacterEncoding("UTF-8");

		// 调用核心业务类接收消息、处理消息
		String respMessage = CoreService.processWebchatRequest(request);

		// 响应消息
		PrintWriter out = null;
		try {
			out = response.getWriter();
			out.print(respMessage);
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			out.close();
			out = null;
		}
	}

}

/**
 * 处理微信发来的请求
 * 
 * @param request
 * @return String
 */
public static String processWebchatRequest(HttpServletRequest request) {
	String respMessage = null;
	try {
		// xml请求解析
		Map<String, String> requestMap = MessageUtil.parseXml(request);
		// 消息类型
		String msgType = requestMap.get("MsgType");

		TextMessage textMessage = (TextMessage) MessageService
				.bulidBaseMessage(requestMap,
						ConstantWeChat.RESP_MESSAGE_TYPE_TEXT);
		NewsMessage newsMessage = (NewsMessage) MessageService
				.bulidBaseMessage(requestMap,
						ConstantWeChat.RESP_MESSAGE_TYPE_NEWS);

		String respContent = "";
		// 文本消息
		if (msgType.equals(ConstantWeChat.REQ_MESSAGE_TYPE_TEXT)) {
			// 接收用户发送的文本消息内容
			String content = requestMap.get("Content");

			List<Article> articleList = new ArrayList<Article>();
			// 单图文消息
			if ("1".equals(content)) {
				Article article = new Article();
				article.setTitle("测试TITLE");
				article.setDescription("测试Description");
				article.setPicUrl("图片地址");
				article.setUrl("https://m.baidu.com");
				articleList.add(article);
				// 设置图文消息个数
				newsMessage.setArticleCount(articleList.size());
				// 设置图文消息包含的图文集合
				newsMessage.setArticles(articleList);
				// 将图文消息对象转换成xml字符串
				respMessage = MessageService.bulidSendMessage(newsMessage,
						ConstantWeChat.RESP_MESSAGE_TYPE_NEWS);
			} else if ("#".equals(content)) {
				textMessage.setContent("###");
				respMessage = MessageService.bulidSendMessage(textMessage,
						ConstantWeChat.RESP_MESSAGE_TYPE_TEXT);
			}
		} else if (msgType.equals(ConstantWeChat.REQ_MESSAGE_TYPE_EVENT)) {
			// 事件类型
			String eventType = requestMap.get("Event");

			if (eventType.equals(ConstantWeChat.EVENT_TYPE_SUBSCRIBE)) {
				// 关注
				respContent = "感谢您关注偶,这里会给您提供最新的公司资讯和公告！\n";
			} else if (eventType
					.equals(ConstantWeChat.EVENT_TYPE_UNSUBSCRIBE)) {
				// 取消关注,用户接受不到我们发送的消息了，可以在这里记录用户取消关注的日志信息
			} else if (eventType.equals(ConstantWeChat.EVENT_TYPE_CLICK)) {
				// 事件KEY值，与创建自定义菜单时指定的KEY值对应
				String eventKey = requestMap.get("EventKey");
				// 自定义菜单点击事件
				if (eventKey.equals("11")) {
					respContent = "天气预报菜单项被点击！";
				} else if (eventKey.equals("12")) {
					respContent = "公交查询菜单项被点击！";
				}
			}
			textMessage.setContent(respContent);
			respMessage = MessageService.bulidSendMessage(textMessage,
					ConstantWeChat.RESP_MESSAGE_TYPE_TEXT);
		}
	} catch (Exception e) {
		e.printStackTrace();
	}
	return respMessage;
}