微信 JAVA

package net.binjoo.wechat;   import java.io.IOException; import java.util.Arrays;   import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;   import net.binjoo.utils.SHA1;   @SuppressWarnings("serial") public class WechatCallbackApi extends HttpServlet { // 自定義 token private String TOKEN = "這個地方由你自己定義";   public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 微信加密簽名 String signature = request.getParameter("signature"); // 隨機字符串 String echostr = request.getParameter("echostr"); // 時間戳 String timestamp = request.getParameter("timestamp"); // 隨機數 String nonce = request.getParameter("nonce");   String[] str = { TOKEN, timestamp, nonce };Arrays.sort(str); // 字典序排序 String bigStr = str[0] + str[1] + str[2]; // SHA1加密String digest = new SHA1().getDigestOfString(bigStr.getBytes()).toLowerCase();   // 確認請求來至微信 if (digest.equals(signature)) { response.getWriter().print(echostr); } } }開啓消息接口