上一篇已经获取到了用户的OpenId
这篇主要是调用微信公众支付的统一下单API
API地址:https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=9_1
看文档,主要流程就是把20个左右的参数封装为XML格式发送到微信给的接口地址,然后就可以获取到返回的内容了,如果成功里面就有支付所需要的预支付ID
请求参数就不解释了。
其中,随机字符串:我用的是UUID去中划线
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public static String create_nonce_str() { return UUID.randomUUID().toString().replace( "-" , "" ); } |
商户订单号:每个订单号只能使用一次,所以用的是系统的订单号加的时间戳。
总金额:不能为
通知地址:微信支付成功或失败回调给系统的地址
签名:
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import java.io.Serializable; public class PayInfo implements Serializable{ private static final long serialVersionUID = L; private String appid; private String mch_id; private String device_info; private String nonce_str; private String sign; private String body; private String attach; private String out_trade_no; private int total_fee; private String spbill_create_ip; private String notify_url; private String trade_type; private String openid; //下面是get,set方法 } /** * 创建统一下单的xml的java对象 * @param bizOrder 系统中的业务单号 * @param ip 用户的ip地址 * @param openId 用户的openId * @return */ public PayInfo createPayInfo(BizOrder bizOrder,String ip,String openId) { PayInfo payInfo = new PayInfo(); payInfo.setAppid(Constants.appid); payInfo.setDevice_info( "WEB" ); payInfo.setMch_id(Constants.mch_id); payInfo.setNonce_str(CommonUtil.create_nonce_str().replace( "-" , "" )); payInfo.setBody( "这里是某某白米饭的body" ); payInfo.setAttach(bizOrder.getId()); payInfo.setOut_trade_no(bizOrder.getOrderCode().concat( "A" ).concat(DateFormatUtils.format( new Date(), "MMddHHmmss" ))); payInfo.setTotal_fee(( int )bizOrder.getFeeAmount()); payInfo.setSpbill_create_ip(ip); payInfo.setNotify_url(Constants.notify_url); payInfo.setTrade_type( "JSAPI" ); payInfo.setOpenid(openId); return payInfo; } |
获取签名:
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/** * 获取签名 * @param payInfo * @return * @throws Exception */ public String getSign(PayInfo payInfo) throws Exception { String signTemp = "appid=" +payInfo.getAppid() + "&attach=" +payInfo.getAttach() + "&body=" +payInfo.getBody() + "&device_info=" +payInfo.getDevice_info() + "&mch_id=" +payInfo.getMch_id() + "&nonce_str=" +payInfo.getNonce_str() + "¬ify_url=" +payInfo.getNotify_url() + "&openid=" +payInfo.getOpenid() + "&out_trade_no=" +payInfo.getOut_trade_no() + "&spbill_create_ip=" +payInfo.getSpbill_create_ip() + "&total_fee=" +payInfo.getTotal_fee() + "&trade_type=" +payInfo.getTrade_type() + "&key=" +Constants.key; //这个key注意 MessageDigest md = MessageDigest.getInstance( "MD" ); md.reset(); md.update(signTemp.getBytes( "UTF-" )); String sign = CommonUtil.byteToStr(md.digest()).toUpperCase(); return sign; } |
注意:上面的Constants.key取值在商户号API安全的API密钥中。
一些工具方法:获取ip地址,将字节数组转换为十六进制字符串,将字节转换为十六进制字符串
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/** * 将字节数组转换为十六进制字符串 * * @param byteArray * @return */ public static String byteToStr( byte [] byteArray) { String strDigest = "" ; for ( int i = ; i < byteArray.length; i++) { strDigest += byteToHexStr(byteArray[i]); } return strDigest; } /** * 将字节转换为十六进制字符串 * * @param btyes * @return */ public static String byteToHexStr( byte bytes) { char [] Digit = { '' , '' , '' , '' , '' , '' , '' , '' , '' , '' , 'A' , 'B' , 'C' , 'D' , 'E' , 'F' }; char [] tempArr = new char []; tempArr[] = Digit[(bytes >>> ) & XF]; tempArr[] = Digit[bytes & XF]; String s = new String(tempArr); return s; } /** * 获取ip地址 * @param request * @return */ public static String getIpAddr(HttpServletRequest request) { InetAddress addr = null ; try { addr = InetAddress.getLocalHost(); } catch (UnknownHostException e) { return request.getRemoteAddr(); } byte [] ipAddr = addr.getAddress(); String ipAddrStr = "" ; for ( int i = ; i < ipAddr.length; i++) { if (i > ) { ipAddrStr += "." ; } ipAddrStr += ipAddr[i] & xFF; } return ipAddrStr; } |
这样就获取了签名,把签名与PayInfo中的其他数据转成XML格式,当做参数传递给统一下单地址。
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PayInfo pi = pu.createPayInfo(bo, "..." , "" ); String sign = pu.getSign(pi); pi.setSign(sign); |
对象转XML
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/** * 扩展xstream使其支持CDATA */ private static XStream xstream = new XStream( new XppDriver() { public HierarchicalStreamWriter createWriter(Writer out) { return new PrettyPrintWriter(out) { //增加CDATA标记 boolean cdata = true ; @SuppressWarnings ( "rawtypes" ) public void startNode(String name, Class clazz) { super .startNode(name, clazz); } protected void writeText(QuickWriter writer, String text) { if (cdata) { writer.write( "<![CDATA[" ); writer.write(text); writer.write( "]]>" ); } else { writer.write(text); } } }; } }); public static String payInfoToXML(PayInfo pi) { xstream.alias( "xml" , pi.getClass()); return xstream.toXML(pi); } |
xml转Map
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@SuppressWarnings ( "unchecked" ) public static Map<String, String> parseXml(String xml) throws Exception { Map<String, String> map = new HashMap<String, String>(); Document document = DocumentHelper.parseText(xml); Element root = document.getRootElement(); List<Element> elementList = root.elements(); for (Element e : elementList) map.put(e.getName(), e.getText()); return map; } |
下面就是调用统一下单的URL了
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log.info(MessageUtil.payInfoToXML(pi).replace( "__" , "_" )); Map<String, String> map = CommonUtil.httpsRequestToXML( "https://api.mch.weixin.qq.com/pay/unifiedorder" , "POST" , MessageUtil.payInfoToXML(pi).replace( "__" , "_" ).replace( "<![CDATA[" , "" ).replace( "]]>" , "" )); log.info(map); public static Map<String, String> httpsRequestToXML(String requestUrl, String requestMethod, String outputStr) { Map<String, String> result = new HashMap<>(); try { StringBuffer buffer = httpsRequest(requestUrl, requestMethod, outputStr); result = MessageUtil.parseXml(buffer.toString()); } catch (ConnectException ce) { log.error( "连接超时:" +ce.getMessage()); } catch (Exception e) { log.error( "https请求异常:" +ece.getMessage()); } return result; } |
httpsRequest()这个方法在第一篇中
上面获取到的Map如果成功的话,里面就会有
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String return_code = map.get( "return_code" ); if (StringUtils.isNotBlank(return_code) && return_code.equals( "SUCCESS" )){ String return_msg = map.get( "return_msg" ); if (StringUtils.isNotBlank(return_msg) && !return_msg.equals( "OK" )) { return "统一下单错误!" ; } } else { return "统一下单错误!" ; } String prepay_Id = map.get( "prepay_id" ); |
这个prepay_id就是预支付的ID。后面支付需要它。