Java微信支付之公众号支付、扫码支付实例

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。