最近项目需要微信支付，然后看了下微信公众号支付，虽然不难，但是细节还是需要注意的，用了大半天时间写了个demo，并且完整的测试了一下支付流程，下面分享一下微信公众号支付的经验。
一、配置公众号微信支付
需要我们配置微信公众号支付地址和测试白名单。
比如：支付JS页面的地址为
那此处配置
二、开发流程
借用微信公众号支付api(地址 )，我们需要开发的为红色标记出的。如下：
三、向微信服务器端下订单
调用统一下单接口，这样就能获取微信支付的prepay_id（）。
在调用该接口前有几个字段是H5支付必须填写的openid
3.1 获取openid
在微信中发送如下链接
https://open.weixin.qq.com/connect/oauth2/authorize?appid=wx520c15f417810387&redirect_uri=要跳转的下订单的url&response_type=code&scope=snsapi_base&state=123#wechat_redirect
3.2 后台支付
代码如下，包含预处理订单，支付订单等接口。
package org.andy.controller; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.io.UnsupportedEncodingException; import java.util.Date; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Map.Entry; import java.util.Random; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.codec.digest.DigestUtils; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.xmlpull.v1.XmlPullParser; import org.xmlpull.v1.XmlPullParserException; import org.xmlpull.v1.XmlPullParserFactory; import com.fasterxml.jackson.databind.JsonNode; import com.gson.oauth.Oauth; import com.gson.oauth.Pay; import com.gson.util.HttpKit; import com.gson.util.Tools; import org.andy.util.DatetimeUtil; import org.andy.util.JsonUtil; import org.andy.util.SessionUtil; import org.andy.util.WebUtil; @Controller @RequestMapping("/pay") public class WXPayController { @RequestMapping(value = "wxprepay") public void jspay(HttpServletRequest request, HttpServletResponse response, String callback) throws Exception { // 获取openid String openId = SessionUtil.getAtt(request, "openId"); if (openId == null) { openId = getUserOpenId(request); } String appid = "wx16691fcb0523c1a4"; String partnerid = "22223670"; String paternerKey = "fjfjfjfjf1234567FFFFFFFFF1234567"; String out_trade_no = getTradeNo(); Map<String, String> paraMap = new HashMap<String, String>(); paraMap.put("appid", appid); paraMap.put("attach", "测试支付"); paraMap.put("body", "测试购买Beacon支付"); paraMap.put("mch_id", partnerid); paraMap.put("nonce_str", create_nonce_str()); paraMap.put("openid", openId); paraMap.put("out_trade_no", out_trade_no); paraMap.put("spbill_create_ip", getAddrIp(request)); paraMap.put("total_fee", "1"); paraMap.put("trade_type", "JSAPI"); paraMap.put("notify_url", "http://www.xxx.co/wxpay/pay/appPay_notify.shtml"); String sign = getSign(paraMap, paternerKey); paraMap.put("sign", sign); // 统一下单 https://api.mch.weixin.qq.com/pay/unifiedorder String url = "https://api.mch.weixin.qq.com/pay/unifiedorder"; String xml = ArrayToXml(paraMap, false); String xmlStr = HttpKit.post(url, xml); // 预付商品id String prepay_id = ""; if (xmlStr.indexOf("SUCCESS") != -1) { Map<String, String> map = doXMLParse(xmlStr); prepay_id = (String) map.get("prepay_id"); } Map<String, String> payMap = new HashMap<String, String>(); payMap.put("appId", appid); payMap.put("timeStamp", create_timestamp()); payMap.put("nonceStr", create_nonce_str()); payMap.put("signType", "MD5"); payMap.put("package", "prepay_id=" + prepay_id); String paySign = getSign(payMap, paternerKey); payMap.put("pg", prepay_id); payMap.put("paySign", paySign); WebUtil.response(response, WebUtil.packJsonp(callback, JsonUtil.warpJsonNodeResponse(JsonUtil.objectToJsonNode(payMap)).toString())); } @RequestMapping(value = "appPay") public void appPay(HttpServletRequest request, HttpServletResponse response, String body, String detail, String total_fee, String spbill_create_ip, String notify_url, String trade_type, String callback) throws Exception { String appid = "wx16691fcb0523c1a4"; String partnerid = "22223670"; String paternerKey = "fjfjfjfjf1234567FFFFFFFFF1234567"; String out_trade_no = getTradeNo(); Map<String, String> paraMap = new HashMap<String, String>(); paraMap.put("appid", appid); paraMap.put("body", body); paraMap.put("mch_id", partnerid); paraMap.put("nonce_str", create_nonce_str()); paraMap.put("out_trade_no", out_trade_no); paraMap.put("spbill_create_ip", spbill_create_ip); paraMap.put("total_fee", total_fee); paraMap.put("trade_type", trade_type); paraMap.put("notify_url", notify_url); String sign = getSign(paraMap, paternerKey); paraMap.put("sign", sign); // 统一下单 https://api.mch.weixin.qq.com/pay/unifiedorder String url = "https://api.mch.weixin.qq.com/pay/unifiedorder"; String xml = ArrayToXml(paraMap, false); String xmlStr = HttpKit.post(url, xml); // 预付商品id String prepay_id = ""; Map<String, String> map = doXMLParse(xmlStr); if (xmlStr.indexOf("SUCCESS") != -1) { prepay_id = (String) map.get("prepay_id"); } String result_code = map.get("result_code"); String err_code_des = map.get("err_code_des"); Map<String, String> payMap = new HashMap<String, String>(); payMap.put("appid", appid); payMap.put("partnerid", partnerid); payMap.put("prepayid", prepay_id); payMap.put("package", "Sign=WXPay"); payMap.put("noncestr", create_nonce_str()); payMap.put("timestamp", create_timestamp()); String paySign = getSign(payMap, paternerKey); payMap.put("sign", paySign); payMap.put("result_code", result_code); payMap.put("err_code_des", err_code_des); WebUtil.response(response, WebUtil.packJsonp(callback, JsonUtil.warpJsonNodeResponse(JsonUtil.objectToJsonNode(payMap)).toString())); } @RequestMapping("/appPay_notify") public void appPayNotify(HttpServletRequest request, HttpServletResponse response) throws Exception{ //String xml = "<xml><appid><![CDATA[wxb4dc385f953b356e]]></appid><bank_type><![CDATA[CCB_CREDIT]]></bank_type><cash_fee><![CDATA[1]]></cash_fee><fee_type><![CDATA[CNY]]></fee_type><is_subscribe><![CDATA[Y]]></is_subscribe><mch_id><![CDATA[1228442802]]></mch_id><nonce_str><![CDATA[1002477130]]></nonce_str><openid><![CDATA[o-HREuJzRr3moMvv990VdfnQ8x4k]]></openid><out_trade_no><![CDATA[1000000000051249]]></out_trade_no><result_code><![CDATA[SUCCESS]]></result_code><return_code><![CDATA[SUCCESS]]></return_code><sign><![CDATA[1269E03E43F2B8C388A414EDAE185CEE]]></sign><time_end><![CDATA[20150324100405]]></time_end><total_fee>1</total_fee><trade_type><![CDATA[JSAPI]]></trade_type><transaction_id><![CDATA[1009530574201503240036299496]]></transaction_id></xml>"; response.setCharacterEncoding("UTF-8"); response.setContentType("text/xml"); ServletInputStream in = request.getInputStream(); String xmlMsg = Tools.inputStream2String(in); Map<String, String> map = doXMLParse(xmlMsg); String return_code = map.get("return_code"); String return_msg = map.get("return_msg"); map = new HashMap<String, String>(); map.put("return_code", return_code); map.put("return_msg", return_msg); //响应xml String resXml = ArrayToXml(map, true); response.getWriter().write(resXml); } @RequestMapping("/orderquery.do") public void orderquery(HttpServletRequest request, HttpServletResponse response, String transaction_id, String out_trade_no, String callback) throws Exception{ String url = "https://api.mch.weixin.qq.com/pay/orderquery"; String appid = "wx16691fcb0523c1a4"; String partnerid = "22223670"; String paternerKey = "fjfjfjfjf1234567FFFFFFFFF1234567"; Map<String, String> map = new HashMap<String, String>(); map.put("appid", appid); map.put("mch_id", partnerid); if(transaction_id != null && !transaction_id.equals("")){ map.put("transaction_id", transaction_id); }else { map.put("out_trade_no", out_trade_no); } map.put("nonce_str", create_nonce_str()); String paySign = getSign(map, paternerKey); map.put("sign", paySign); String xml = ArrayToXml(map, false); String xmlStr = HttpKit.post(url, xml); Map<String, String> orderMap = doXMLParse(xmlStr); WebUtil.response(response, WebUtil.packJsonp(callback, JsonUtil.warpJsonNodeResponse(JsonUtil.objectToJsonNode(orderMap)).toString())); } /** * map转成xml * * @param arr * @return */ public String ArrayToXml(Map<String, String> parm, boolean isAddCDATA) { StringBuffer strbuff = new StringBuffer(<xml>); if (parm != null ) { for (Entry<String, String> entry : parm.entrySet()) { strbuff.append("<").append(entry.getKey()).append(">"); if (isAddCDATA) { strbuff.append(<![CDATA[).append(entry.getValue()).append(]]>); }else { strbuff.append(entry.getValue()); } strbuff.append("<").append(entry.getKey()).append(">"); } } return strbuff.append(</xml>).toString(); } // 获取openId private String getUserOpenId(HttpServletRequest request) throws Exception { String code = request.getParameter("code"); if (code == null) { String openId = request.getParameter("openId"); return openId; } Oauth o = new Oauth(); String token = o.getToken(code); JsonNode node = JsonUtil.StringToJsonNode(token); String openId = node.get("openid").asText(); return openId; } private String create_nonce_str() { String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; String res = ""; for (int i = 0; i < 16; i++) { Random rd = new Random(); res += chars.charAt(rd.nextInt(chars.length() - 1)); } return res; } private String getAddrIp(HttpServletRequest request){ return request.getRemoteAddr(); } private String create_timestamp() { return Long.toString(System.currentTimeMillis() / 1000); } private String getTradeNo(){ String timestamp = DatetimeUtil.formatDate(new Date(), DatetimeUtil.DATETIME_PATTERN); return "HZNO" + timestamp; } private String getSign(Map<String, String> params, String paternerKey ) throws UnsupportedEncodingException { String string1 = Pay.createSign(params, false); String stringSignTemp = string1 + "&key=" + paternerKey; String signValue = DigestUtils.md5Hex(stringSignTemp).toUpperCase(); return signValue; } private Map<String, String> doXMLParse(String xml) throws XmlPullParserException, IOException { InputStream inputStream = new ByteArrayInputStream(xml.getBytes()); Map<String, String> map = null; XmlPullParser pullParser = XmlPullParserFactory.newInstance() .newPullParser(); pullParser.setInput(inputStream, "UTF-8"); // 为xml设置要解析的xml数据 int eventType = pullParser.getEventType(); while (eventType != XmlPullParser.END_DOCUMENT) { switch (eventType) { case XmlPullParser.START_DOCUMENT: map = new HashMap<String, String>(); break; case XmlPullParser.START_TAG: String key = pullParser.getName(); if (key.equals("xml")) break; String value = pullParser.nextText(); map.put(key, value); break; case XmlPullParser.END_TAG: break; } eventType = pullParser.next(); } return map; } }