微信平台申请消息接口时Signature校验的Servlet实现
看到一个朋友弄了微信公众帐号，我自己也弄了一个。根据说明，要想成为开发者，需要有一个自己的网站，并且处理校验一个微信传来的GET请求。我就按要求弄了一个。
具体的要求如下：
http://mp.weixin.qq.com/wiki/index.php?title=消息接口指南

下面是我的实现。先写一个Servlet

package me.gimli.wx.echo;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import me.gimli.wx.util.SignatureChecker;@SuppressWarnings("serial")public class EchoServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {String signature = req.getParameter("signature");String timestamp = req.getParameter("timestamp");String nonce = req.getParameter("nonce");String echostr = req.getParameter("echostr");SignatureChecker checker = new SignatureChecker();if (checker.checkSigature(signature, timestamp, nonce)){resp.getWriter().print(echostr);}else {resp.getWriter().print("validation failed. Bye");}}}

SignatureChecker 工具类：

package me.gimli.wx.util;import java.security.MessageDigest;import java.util.Arrays;public class SignatureChecker {public boolean checkSigature(String signature,String timestamp,String nonce){//Define tokenString token = "ABC123def456";//Sort arrayString[] tmparr = {token,timestamp,nonce};try {Arrays.sort(tmparr);} catch (NullPointerException e){return false;}//implode arrayStringBuilder builder = new StringBuilder();for (int i=0;i<tmparr.length;i++){builder.append(tmparr[i]);}String raw = builder.toString();//SHA-1    MessageDigest md = null;    byte[] b = null;    try {        md = MessageDigest.getInstance("SHA-1");        b = md.digest(raw.getBytes("UTF-8"));    }    catch(Exception e) {        e.printStackTrace();    }         //Turn sha-1 result to HexStringString result = "";for (int i=0; i < b.length; i++) {    result += Integer.toString( ( b[i] & 0xff ) + 0x100, 16).substring( 1 );}//Compare and returnif (result.equals(signature)){return true;}else{return false;}}}

然后再在web.xml中部署上就可以了

  <servlet>  <servlet-name>echo</servlet-name>  <servlet-class>me.gimli.wx.echo.EchoServlet</servlet-class>  </servlet>    <servlet-mapping>  <servlet-name>echo</servlet-name>  <url-pattern>/saldar/*</url-pattern>  </servlet-mapping>

最后以微信广告语结束：再小的个体，也有自己的品牌。