消息事件接收

package weixin.popular.example;

import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import weixin.popular.bean.message.EventMessage;
import weixin.popular.bean.xmlmessage.XMLMessage;
import weixin.popular.bean.xmlmessage.XMLTextMessage;
import weixin.popular.support.ExpireKey;
import weixin.popular.support.expirekey.DefaultExpireKey;
import weixin.popular.util.SignatureUtil;
import weixin.popular.util.XMLConverUtil;

/**
 * 服务端事件消息接收
 *
 * @author Yi
 */
public class ReceiveServlet extends HttpServlet {

  /**
   *
   */
  private static final long serialVersionUID = 1L;
  //重复通知过滤
  private static ExpireKey expireKey = new DefaultExpireKey();
  //从官方获取
  private String token = "test";

  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    ServletOutputStream outputStream = response.getOutputStream();
    String signature = request.getParameter("signature");
    String timestamp = request.getParameter("timestamp");
    String nonce = request.getParameter("nonce");
    String echostr = request.getParameter("echostr");

    //首次请求申请验证,返回echostr
    if (echostr != null) {
      outputStreamWrite(outputStream, echostr);
      return;
    }

    //验证请求签名
    if (!signature.equals(SignatureUtil.generateEventMessageSignature(token, timestamp, nonce))) {
      System.out.println("The request signature is invalid");
      return;
    } else {
      outputStreamWrite(outputStream, echostr);
      return;
    }
  }

  @Override
  protected void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    ServletInputStream inputStream = request.getInputStream();
    ServletOutputStream outputStream = response.getOutputStream();
    String signature = request.getParameter("signature");
    String timestamp = request.getParameter("timestamp");
    String nonce = request.getParameter("nonce");
    String echostr = request.getParameter("echostr");

    //首次请求申请验证,返回echostr
    if (echostr != null) {
      outputStreamWrite(outputStream, echostr);
      return;
    }

    //验证请求签名
    if (!signature.equals(SignatureUtil.generateEventMessageSignature(token, timestamp, nonce))) {
      System.out.println("The request signature is invalid");
      return;
    }

    if (inputStream != null) {
      //转换XML
      EventMessage eventMessage = XMLConverUtil.convertToObject(EventMessage.class, inputStream);
      String key = eventMessage.getFromUserName() + "__"
          + eventMessage.getToUserName() + "__"
          + eventMessage.getMsgId() + "__"
          + eventMessage.getCreateTime();
      if (expireKey.exists(key)) {
        //重复通知不作处理
        return;
      } else {
        expireKey.add(key);
      }

      //创建回复
      XMLMessage xmlTextMessage = new XMLTextMessage(
          eventMessage.getFromUserName(),
          eventMessage.getToUserName(),
          "你好");
      //回复
      xmlTextMessage.outputStreamWrite(outputStream);
      return;
    }
    outputStreamWrite(outputStream, "");
  }

  /**
   * 数据流输出
   */
  private boolean outputStreamWrite(OutputStream outputStream, String text) {
    try {
      outputStream.write(text.getBytes("utf-8"));
    } catch (UnsupportedEncodingException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      return false;
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      return false;
    }
    return true;
  }
}