ReceiveServlet.java

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;

	//从官方获取
	private String token = "test";

	//重复通知过滤
    private static ExpireKey expireKey = new DefaultExpireKey();

    @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
     * @param outputStream
     * @param text
     * @return
     */
    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;
    }
}