模拟建行网上支付服务器通知

Code
String posID = request.getParameter("POSID");  //POSID    商户柜台代码    CHAR(9)    从商户传送的信息中获得
        String branchID = request.getParameter("BRANCHID");  //BRANCHID    分行代码    CHAR(9)    从商户传送的信息中获得
        String orderID = request.getParameter("ORDERID");  //ORDERID    定单号    CHAR(30)    从商户传送的信息中获得
        String payment = request.getParameter("PAYMENT");  //PAYMENT    付款金额    NUMBER(16,2)    从商户传送的信息中获得
        String curCode = request.getParameter("CURCODE");  //CURCODE    币种    CHAR(2)    从商户传送的信息中获得
        String remark1 = new String(request.getParameter("REMARK1").getBytes(this.getServletContext().getInitParameter("URLEncoding")),this.getServletContext().getInitParameter("Encoding"));//REMARK1    备注1    CHAR(30)    网银不处理，直接传到城综网
        String remark2 = new String(request.getParameter("REMARK2").getBytes(this.getServletContext().getInitParameter("URLEncoding")),this.getServletContext().getInitParameter("Encoding"));//REMARK2    备注2    CHAR(30)    网银不处理，直接传到城综网
        String accType = request.getParameter("ACC_TYPE");  //ACC_TYPE    帐户类型    CHAR(2)    从银行信息中获得
        String success = request.getParameter("SUCCESS");  //SUCCESS    成功标志    CHAR(1)    成功时返回Y   N
        String sign = request.getParameter("SIGN");  //SIGN    数字签名    CHAR(256)    

        StringBuffer src = new StringBuffer();
        src.append("POSID=" + posID);
        src.append("&BRANCHID=" + branchID);
        src.append("&ORDERID=" + orderID);
        src.append("&PAYMENT=" + payment);
        src.append("&CURCODE=" + curCode);
        src.append("&REMARK1=" + remark1);
        src.append("&REMARK2=" + remark2);
        src.append("&ACC_TYPE=" + accType);
        src.append("&SUCCESS=" + success);

        RSASig rsaSig = new RSASig();
        rsaSig.setPrivateKey(this.getInitParameter("PrivateKey"));
        sign = rsaSig.generateSigature(src.toString());

        StringBuffer url = new StringBuffer();
        url.append(this.getInitParameter("ServerNoticeUrl"));
        url.append("?POSID=" + posID);
        url.append("&BRANCHID=" + branchID);
        url.append("&ORDERID=" + orderID);
        url.append("&PAYMENT=" + payment);
        url.append("&CURCODE=" + curCode);
        url.append("&REMARK1=" + URLEncoder.encode(remark1,this.getServletContext().getInitParameter("Encoding")));
        url.append("&REMARK2=" + URLEncoder.encode(remark2,this.getServletContext().getInitParameter("Encoding")));
        url.append("&ACC_TYPE=" + accType);
        url.append("&SUCCESS=" + success);
        url.append("&SIGN=" + sign);
        
        log.debug("src:" + src.toString());
        log.debug("sign:" + sign);
        log.debug("url:" + url.toString());
        response.sendRedirect(url.toString());