做过工行接口的都进来看看吧
StringBuilder strSet = new StringBuilder();
            strSet.Append("<?xml version=\"1.0\" encoding=\"GBK\" standalone=\"no\"?>");
            strSet.Append("<B2CReq>");
            strSet.Append("<interfaceName>ICBC_PERBANK_B2C</interfaceName>");
            strSet.Append("<interfaceVersion>1.0.0.14</interfaceVersion>");
            strSet.Append("<orderInfo>");
            strSet.Append("<orderDate>20120715154033</orderDate>");
            strSet.Append("<curType>001</curType>");//支付币种
            strSet.Append("<merID>0409EC23772721</merID>");//商户代码
            strSet.Append("<subOrderInfoList>");
            strSet.Append("<subOrderInfo>");
            strSet.Append("<orderid>123123123</orderid>");//订单号
            strSet.Append("<amount>1</amount>");   //数值
            strSet.Append("<installmentTimes>1</installmentTimes>");//分期付款期数    
            strSet.Append("<merAcct>0409001219300035126</merAcct>");//商户账号
            strSet.Append("<goodsID>001</goodsID>");//商品编号
            strSet.Append("<goodsName>123123</goodsName>");//商品名称
            strSet.Append("<goodsNum>1</goodsNum>");//商品数量
            strSet.Append("<carriageAmt>0</carriageAmt>");//已含运费金额
            strSet.Append("</subOrderInfo>");
            strSet.Append("</subOrderInfoList>");
            strSet.Append("</orderInfo>");
            strSet.Append("<custom>");
            strSet.Append("<verifyJoinFlag>0</verifyJoinFlag>");//检验联名标志
            strSet.Append("<Language>ZH_CN</Language>");//语言版本
            strSet.Append("<HangSupportFlag>1</HangSupportFlag><HangTimeInterval>24</HangTimeInterval>");
            strSet.Append("</custom>");
            strSet.Append("<message>");
            strSet.Append("<creditType>2</creditType>");//支持订单支付的银行卡种类