微信支付现在已经变得越来越流行了，随之也出现了很多以可以快速接入微信支付为噱头的产品，不过方便之余也使得我们做东西慢慢依赖第三方，丧失了独立思考的能力，这次打算分享下我之前开发过的微信支付。
一 、H5公众号支付
要点：正确获取openId以及统一下单接口，正确处理支付结果通知，正确配置支付授权目录
H5的支付方式是使用较为广泛的方式，这种支付方式主要用于微信内自定义菜单的网页，依赖手机上安装的微信客户端，高版本的微信才支持微信支付，下面按我的流程注意说明
1 编写用于支付的页面，由于是测试用就写的简单了点
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>微信支付样例</title> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <form action="oauthServlet" method="POST"> 订单号：<input type="text" name="orderNo" /> <input type="submit" value="H5支付"/> </form> </br></br> <form action="scanCodePayServlet?flag=createCode" method="POST"> 订单号：<input type="text" name="orderNo" /> <input type="submit" value="扫码支付"/> </form> </body> </html>
2 编写一个servlet用于通过Oauth获取code
package com.debug.weixin.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.debug.weixin.util.CommonUtil; import com.debug.weixin.util.ServerConfig; public class OauthServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String orderNo=request.getParameter("orderNo"); //调用微信Oauth2.0获取openid String redirectURL=ServerConfig.SERVERDOMAIN+"/BasicWeixin/payServletForH5?orderNo="+orderNo; String redirectURI=""; try { redirectURI=CommonUtil.initOpenId(redirectURL); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } //System.out.println(redirectURI); //RequestDispatcher dis= request.getRequestDispatcher(redirectURI); //dis.forward(request, response); response.sendRedirect(redirectURI); } } 3 获取到code后，通过REDIRECTURI获取openId,调用统一下单接口
package com.debug.weixin.servlet; import java.io.IOException; import java.io.PrintWriter; import java.util.SortedMap; import java.util.TreeMap; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.debug.weixin.pojo.WeixinOauth2Token; import com.debug.weixin.pojo.WeixinQRCode; import com.debug.weixin.util.AdvancedUtil; import com.debug.weixin.util.CommonUtil; import com.debug.weixin.util.ConfigUtil; import com.debug.weixin.util.PayCommonUtil; public class PayServletForH5 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String orderNo=request.getParameter("orderNo"); String code=request.getParameter("code"); //获取AccessToken WeixinOauth2Token token=AdvancedUtil.getOauth2AccessToken(ConfigUtil.APPID, ConfigUtil.APP_SECRECT, code); String openId=token.getOpenId(); //调用微信统一支付接口 SortedMap<Object, Object> parameters = new TreeMap<Object, Object>(); parameters.put("appid", ConfigUtil.APPID); parameters.put("mch_id", ConfigUtil.MCH_ID); parameters.put("device_info", "1000"); parameters.put("body", "我的测试订单"); parameters.put("nonce_str", PayCommonUtil.CreateNoncestr()); parameters.put("out_trade_no", orderNo); //parameters.put("total_fee", String.valueOf(total)); parameters.put("total_fee", "1"); parameters.put("spbill_create_ip", request.getRemoteAddr()); parameters.put("notify_url", ConfigUtil.NOTIFY_URL); parameters.put("trade_type", "JSAPI"); parameters.put("openid", openId); String sign = PayCommonUtil.createSign("UTF-8", parameters); parameters.put("sign", sign); String requestXML = PayCommonUtil.getRequestXml(parameters); String result = CommonUtil.httpsRequestForStr(ConfigUtil.UNIFIED_ORDER_URL,"POST", requestXML); System.out.println("----------------------------------"); System.out.println(result); System.out.println("----------------------------------"); request.setAttribute("orderNo", orderNo); request.setAttribute("totalPrice", "0.01"); String payJSON=""; try { payJSON=CommonUtil.getH5PayStr(result,request); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } //System.out.println(payJSON); request.setAttribute("unifiedOrder",payJSON); RequestDispatcher dis= request.getRequestDispatcher("h5Pay.jsp"); dis.forward(request, response); } } 调用微信统一下单接口，需要注意签名算法，只有签名计算正确才能顺利支付
public static String getH5PayStr(String result,HttpServletRequest request) throws Exception{ Map<String, String> map = XMLUtil.doXMLParse(result); SortedMap<Object,Object> params = new TreeMap<Object,Object>(); params.put("appId", ConfigUtil.APPID); params.put("timeStamp", Long.toString(new Date().getTime())); params.put("nonceStr", PayCommonUtil.CreateNoncestr()); params.put("package", "prepay_id="+map.get("prepay_id")); params.put("signType", ConfigUtil.SIGN_TYPE); String paySign = PayCommonUtil.createSign("UTF-8", params); params.put("paySign", paySign); //paySign的生成规则和Sign的生成规则一致 String json = JSONObject.fromObject(params).toString(); return json; } 4 编写最终的支付界面调起微信H5支付
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>微信H5支付</title> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0"> <script type="text/javascript"> function jsApiCall(){ WeixinJSBridge.invoke( 'getBrandWCPayRequest',<%=(String)request.getAttribute("unifiedOrder")%>, function(res){ WeixinJSBridge.log(res.err_msg); //alert(res.err_code+res.err_desc+res.err_msg); if(res.err_msg == "get_brand_wcpay_request:ok" ) { alert("恭喜你,支付成功!"); }else{ alert(res.err_code+res.err_desc+res.err_msg); } } ); } function callpay(){ if (typeof WeixinJSBridge == "undefined"){ if( document.addEventListener ){ document.addEventListener('WeixinJSBridgeReady', jsApiCall, false); }else if (document.attachEvent){ document.attachEvent('WeixinJSBridgeReady', jsApiCall); document.attachEvent('onWeixinJSBridgeReady', jsApiCall); } }else{ jsApiCall(); } } </script> </head> <body> <input type="button" value="支付" onclick="callpay()"/> </body> </html> 5 处理微信支付结果通知
package com.debug.weixin.servlet; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Map; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.jdom.JDOMException; import com.debug.weixin.util.PayCommonUtil; import com.debug.weixin.util.XMLUtil; public class PayHandlerServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { InputStream inStream = request.getInputStream(); ByteArrayOutputStream outSteam = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while ((len = inStream.read(buffer)) != -1) { outSteam.write(buffer, 0, len); } outSteam.close(); inStream.close(); String result = new String(outSteam.toByteArray(),"utf-8");//获取微信调用我们notify_url的返回信息 Map<Object, Object> map=null; try { map = XMLUtil.doXMLParse(result); } catch (JDOMException e) { // TODO Auto-generated catch block e.printStackTrace(); } for(Object keyValue : map.keySet()){ System.out.println(keyValue+"="+map.get(keyValue)); } if (map.get("result_code").toString().equalsIgnoreCase("SUCCESS")) { //对订单进行业务操作 System.out.println("-------------OK"); response.getWriter().write(PayCommonUtil.setXML("SUCCESS", "")); //告诉微信服务器，我收到信息了，不要在调用回调action了 } } } 对于上面的代码，有很多都是参考http://blog.csdn.net/u011160656/article/details/41759195，因此这部分的代码就不贴出来了，需要的话看这个博客就知道了。
二 微信扫码支付（模式一）
要点：必须调用长链接转短链接接口、正确配置扫码支付回调URL
1 根据订单号生成微信支付二维码
下面是几个生成二维码的方法：
package com.debug.weixin.util; import com.google.zxing.common.BitMatrix; import javax.imageio.ImageIO; import java.io.File; import java.io.OutputStream; import java.io.IOException; import java.awt.image.BufferedImage; public final class MatrixToImageWriter { private static final int BLACK = 0xFF000000; private static final int WHITE = 0xFFFFFFFF; private MatrixToImageWriter() {} public static BufferedImage toBufferedImage(BitMatrix matrix) { int width = matrix.getWidth(); int height = matrix.getHeight(); BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); for (int x = 0; x < width; x++) { for (int y = 0; y < height; y++) { image.setRGB(x, y, matrix.get(x, y) ? BLACK : WHITE); } } return image; } public static void writeToFile(BitMatrix matrix, String format, File file) throws IOException { BufferedImage image = toBufferedImage(matrix); if (!ImageIO.write(image, format, file)) { throw new IOException("Could not write an image of format " + format + " to " + file); } } public static void writeToStream(BitMatrix matrix, String format, OutputStream stream) throws IOException { BufferedImage image = toBufferedImage(matrix); if (!ImageIO.write(image, format, stream)) { throw new IOException("Could not write an image of format " + format); } } } 这个算是工具类，还有一个就是把二维码显示在界面上的方法，CreateQRCode主要用到代码块：
public static void createCodeStream(String text,HttpServletResponse response) throws Exception{ // response.setContentType("image/jpeg"); ServletOutputStream sos = response.getOutputStream(); int width = 500; int height = 500; //二维码的图片格式 String format = "jpg"; MultiFormatWriter multiFormatWriter = new MultiFormatWriter(); Map hints = new HashMap(); //内容所使用编码 hints.put(EncodeHintType.CHARACTER_SET, "UTF-8"); BitMatrix bitMatrix = multiFormatWriter.encode(text, BarcodeFormat.QR_CODE, width, height, hints); //生成二维码 MatrixToImageWriter.writeToStream(bitMatrix, format,sos); sos.close(); } 2 长链接转短链接生成二维码，编写扫码支付回调方法并调用统一下单接口
package com.debug.weixin.servlet; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Date; import java.util.Map; import java.util.SortedMap; import java.util.TreeMap; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.jdom.JDOMException; import com.debug.weixin.util.CommonUtil; import com.debug.weixin.util.ConfigUtil; import com.debug.weixin.util.CreateQRCode; import com.debug.weixin.util.PayCommonUtil; import com.debug.weixin.util.XMLUtil; import com.mongodb.DBObject; public class ScanCodePayServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String flag=request.getParameter("flag"); if("createCode".equals(flag)){ createPayCode(request,response); }else{ try { wxScanCodeHandler(request,response); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } } public void createPayCode(HttpServletRequest request,HttpServletResponse response){ String orderNo=request.getParameter("orderNo"); SortedMap<Object,Object> paras = new TreeMap<Object,Object>(); paras.put("appid", ConfigUtil.APPID); paras.put("mch_id", ConfigUtil.MCH_ID); paras.put("time_stamp", Long.toString(new Date().getTime())); paras.put("nonce_str", PayCommonUtil.CreateNoncestr()); paras.put("product_id", orderNo);//商品号要唯一 String sign = PayCommonUtil.createSign("UTF-8", paras); paras.put("sign", sign); String url = "weixin://wxpay/bizpayurl?sign=SIGN&appid=APPID&mch_id=MCHID&product_id=PRODUCTID&time_stamp=TIMESTAMP&nonce_str=NOCESTR"; String nativeUrl = url.replace("SIGN", sign).replace("APPID", ConfigUtil.APPID).replace("MCHID", ConfigUtil.MCH_ID).replace("PRODUCTID", (String)paras.get("product_id")).replace("TIMESTAMP", (String)paras.get("time_stamp")).replace("NOCESTR", (String)paras.get("nonce_str")); SortedMap<Object,Object> parameters = new TreeMap<Object,Object>(); parameters.put("appid", ConfigUtil.APPID); parameters.put("mch_id", ConfigUtil.MCH_ID); parameters.put("nonce_str", PayCommonUtil.CreateNoncestr()); parameters.put("long_url", CommonUtil.urlEncodeUTF8(nativeUrl)); String sign2 = PayCommonUtil.createSign("UTF-8", parameters); parameters.put("sign", sign2); String requestXML = PayCommonUtil.getRequestXml(parameters); String result =CommonUtil.httpsRequestForStr(ConfigUtil.SHORT_URL, "POST", requestXML); Map<String, String> map=null; try { map = XMLUtil.doXMLParse(result); } catch (JDOMException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } String returnCode = map.get("return_code"); String resultCode = map.get("result_code"); if(returnCode.equalsIgnoreCase("SUCCESS")&&resultCode.equalsIgnoreCase("SUCCESS")){ String shortUrl = map.get("short_url"); //TODO 拿到shortUrl，写代码生成二维码 System.out.println("shortUrl="+shortUrl); try { CreateQRCode.createCodeStream(shortUrl,response); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } } public void wxScanCodeHandler(HttpServletRequest request,HttpServletResponse response) throws Exception { InputStream inStream = request.getInputStream(); ByteArrayOutputStream outSteam = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len = 0; while ((len = inStream.read(buffer)) != -1) { outSteam.write(buffer, 0, len); } outSteam.close(); inStream.close(); String result = new String(outSteam.toByteArray(),"utf-8");//获取微信调用我们notify_url的返回信息 Map<Object, Object> map=null; try { map = XMLUtil.doXMLParse(result); } catch (JDOMException e) { // TODO Auto-generated catch block e.printStackTrace(); } for(Object keyValue : map.keySet()){ System.out.println(keyValue+"="+map.get(keyValue)); } String orderNo=map.get("product_id").toString(); //接收到请求参数后调用统一下单接口 SortedMap<Object, Object> parameters = new TreeMap<Object, Object>(); parameters.put("appid", ConfigUtil.APPID); parameters.put("mch_id", ConfigUtil.MCH_ID); parameters.put("device_info", "1000"); parameters.put("body", "测试扫码支付订单"); parameters.put("nonce_str", PayCommonUtil.CreateNoncestr()); parameters.put("out_trade_no", map.get("product_id")); //parameters.put("total_fee", String.valueOf(totalPrice)); parameters.put("total_fee", "1"); parameters.put("spbill_create_ip", request.getRemoteAddr()); parameters.put("notify_url", ConfigUtil.NOTIFY_URL); parameters.put("trade_type", "NATIVE"); parameters.put("openid", map.get("openid")); String sign = PayCommonUtil.createSign("UTF-8", parameters); parameters.put("sign", sign); String requestXML = PayCommonUtil.getRequestXml(parameters); String result2 = CommonUtil.httpsRequestForStr(ConfigUtil.UNIFIED_ORDER_URL,"POST", requestXML); System.out.println("-----------------------------统一下单结果---------------------------"); System.out.println(result2); Map<String, String> mm=null; try { mm=getH5PayMap(result2,request); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } //String prepayId=getPrepayId(result2,request); //String returnNoneStr=getReturnNoneStr(result2,request); String prepayId=mm.get("prepay_id"); String returnNoneStr=mm.get("nonce_str");; SortedMap<Object, Object> lastSign = new TreeMap<Object, Object>(); lastSign.put("return_code", "SUCCESS"); lastSign.put("appid", ConfigUtil.APPID); lastSign.put("mch_id", ConfigUtil.MCH_ID); lastSign.put("nonce_str", returnNoneStr); lastSign.put("prepay_id", prepayId); lastSign.put("result_code", "SUCCESS"); lastSign.put("key", ConfigUtil.API_KEY); String lastSignpara = PayCommonUtil.createSign("UTF-8", lastSign); StringBuffer buf=new StringBuffer(); buf.append("<xml>"); buf.append("<return_code>SUCCESS</return_code>"); buf.append("<appid>"+ConfigUtil.APPID+"</appid>"); buf.append("<mch_id>"+ConfigUtil.MCH_ID+"</mch_id>"); buf.append("<nonce_str>"+returnNoneStr+"</nonce_str>"); buf.append("<prepay_id>"+prepayId+"</prepay_id>"); buf.append("<result_code>SUCCESS</result_code>"); buf.append("<sign>"+lastSignpara+"</sign>"); buf.append("</xml>"); response.getWriter().print(buf.toString()); } public Map<String, String> getH5PayMap(String result,HttpServletRequest request) throws Exception{ Map<String, String> map = XMLUtil.doXMLParse(result); return map; } } 最终看下公众号支付和扫码支付的微信配置：
希望通过这篇文章，大家能明白就算通过Java来做微信公众号、微信支付而不借助github提供的那些坑人的代码也可以开发出另自己和客户满意的微信应用。虽然微信给出的demo都是PHP的，但这些都是浮云，开发语言是其次，理解接口调用需具备的底层只是才是程序员的必修课。