package com.jysoft;

import java.io.IOException;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.jysoft.weChat.util.MessageUtil;
import com.jysoft.weChat.util.WechatUtil;


public class WeChatServlet extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = -1886413874581936428L;
	/*
	 * 自定义token, 用作生成签名,从而验证安全性
	 */
	private final String TOKEN = "asdfgh";

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// 消息响应
		request.setCharacterEncoding("UTF-8");
		response.setCharacterEncoding("UTF-8");
		System.out.println("请求进来了");
		String result = "";

		try {
			Map<String, String> map = MessageUtil.parseXml(request);
			System.out.println("开始构造消息");
			// 构造响应消息
			result = MessageUtil.buildXml(map);
			System.out.println(result);

			if (result.equals("")) {
				result = "未正确响应";
			}
		} catch (Exception e) {
			e.printStackTrace();
			System.out.println("发生异常：" + e.getMessage());
		}
		// 返回结果
		response.getWriter().println(result);
		System.out.println("请求结束");
	}

	@Override
	public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("-----开始校验签名-----");

		/**
		 * 接收微信服务器发送请求时传递过来的参数
		 */
		String signature = req.getParameter("signature");
		String timestamp = req.getParameter("timestamp");
		String nonce = req.getParameter("nonce"); // 随机数
		String echostr = req.getParameter("echostr");// 随机字符串

		/**
		 * 将token、timestamp、nonce三个参数进行字典序排序 并拼接为一个字符串
		 */

		String sortStr = WechatUtil.sort(TOKEN, timestamp, nonce);
		/**
		 * 字符串进行shal加密
		 */
		String mySignature = WechatUtil.shal(sortStr);
		/**
		 * 校验微信服务器传递过来的签名 和 加密后的字符串是否一致, 若一致则签名通过
		 */
		if (!"".equals(signature) && !"".equals(mySignature) && signature.equals(mySignature)) {
			System.out.println("-----签名校验通过-----");
			resp.getWriter().write(echostr);
		} else {
			System.out.println("-----校验签名失败-----");
		}
	}

}