步骤：
1.预订单
2.接受微信返回的url
3.将url转为二维码显示到页面上
4.扫码支付
5.接收微信的异步通知，在这步修改订单的状态
6.收到异步通知的同时给微信返回指定数据，告知对方已成功处理异步通知
难点：
1.根据传递的参数生成签名
2.将数据转为xml格式发送给微信预订单接口
常见错误：
1.签名错误（推荐用微信的验签工具检验）
2.xml格式错误（很有可能是发送数据的方式出现了问题）
具体实现：
1.预订单
public String getImageUrl(String body,String out_trade_no,String product_id,String total_fee) throws Exception{
Map<String, Object> paramMap = new HashMap<String, Object>();
paramMap.put("appid", data.getAppid()); //appid：每个公众号都有一个appid
paramMap.put("body", body); //商品描述
paramMap.put("mch_id", data.getMch_id()); //商户号：开通微信支付后分配
paramMap.put("nonce_str", RandomStringGenerator.getRandomStringByLength(32)); // 随机字符串
paramMap.put("notify_url", data.getNotify_url()); //支付成功后，回调地址
paramMap.put("out_trade_no", out_trade_no); //商户订单号
paramMap.put("product_id", product_id); // 商户根据自己业务传递的参数 当trade_type=NATIVE时必填
paramMap.put("spbill_create_ip", this.localIp()); //本机的Ip
paramMap.put("total_fee", total_fee); //金额必须为整数 单位为分
paramMap.put("trade_type", data.getTrade_type()); //交易类型
paramMap.put("sign", WxzfUtil.getSign(paramMap, WXPayAction.KEY));//根据微信签名规则，生成签名。随机参数可以在商户后台管理系统中进行设置。
String xmlData = XmlUtils.map2xmlBody(paramMap,"xml");//把参数转换成XML数据格式
String codeUrl = getCodeUrl(xmlData); //获取二维码链接
return codeUrl;
}
public static String getSign(Map map, String key) throws Exception {
String signTemp = "appid=" + map.get("appid") + "&body="
+ map.get("body") + "&mch_id=" + map.get("mch_id")
+ "&nonce_str=" + map.get("nonce_str") + "¬ify_url="
+ map.get("notify_url") + "&out_trade_no="
+ map.get("out_trade_no") + "&product_id="
+ map.get("product_id") + "&spbill_create_ip="
+ map.get("spbill_create_ip") + "&total_fee="
+ map.get("total_fee") + "&trade_type=" + map.get("trade_type")
+ "&key=" + key;
String sign = MD5.MD5Encode(signTemp).toUpperCase();//MD5微信接口中提供，直接调用即可
return sign;
}
public static String map2xmlBody(Map<String, Object> vo, String rootElement) {
org.dom4j.Document doc = DocumentHelper.createDocument();
Element body = DocumentHelper.createElement(rootElement);
doc.add(body);
__buildMap2xmlBody(body, vo);
return doc.asXML();
}
@SuppressWarnings("unchecked")
private static void __buildMap2xmlBody(Element body, Map<String, Object> vo) {
if (vo != null) {
Iterator<String> it = vo.keySet().iterator();
while (it.hasNext()) {
String key = (String) it.next();
if (StringUtil.isNotEmpty(key)) {
Object obj = vo.get(key);
Element element = DocumentHelper.createElement(key);
if (obj != null) {
if (obj instanceof java.lang.String) {
element.setText((String) obj);
} else {
if (obj instanceof java.lang.Character || obj instanceof java.lang.Boolean || obj instanceof java.lang.Number
|| obj instanceof java.math.BigInteger || obj instanceof java.math.BigDecimal) {
org.dom4j.Attribute attr = DocumentHelper.createAttribute(element, "type", obj.getClass().getCanonicalName());
element.add(attr);
element.setText(String.valueOf(obj));
} else if (obj instanceof java.util.Map) {
org.dom4j.Attribute attr = DocumentHelper.createAttribute(element, "type", java.util.Map.class.getCanonicalName());
element.add(attr);
__buildMap2xmlBody(element, (Map<String, Object>) obj);
} else {
}
}
}
body.add(element);
}
}
}
}
/**
* 获取一定长度的随机字符串
* @param length 指定字符串长度
* @return 一定长度的字符串
*/
public static String getRandomStringByLength(int length) {
String base = "abcdefghijklmnopqrstuvwxyz0123456789";
Random random = new Random();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < length; i++) {
int number = random.nextInt(base.length());
sb.append(base.charAt(number));
}
return sb.toString();
}
//获取本机ip地址
@SuppressWarnings("rawtypes")
private String localIp(){
String ip = null;
Enumeration allNetInterfaces;
try {
allNetInterfaces = NetworkInterface.getNetworkInterfaces();
while (allNetInterfaces.hasMoreElements()) {
NetworkInterface netInterface = (NetworkInterface) allNetInterfaces.nextElement();
List<InterfaceAddress> InterfaceAddress = netInterface.getInterfaceAddresses();
for (InterfaceAddress add : InterfaceAddress) {
InetAddress Ip = add.getAddress();
if (Ip != null && Ip instanceof Inet4Address) {
ip = Ip.getHostAddress();
}
}
}
} catch (SocketException e) {
log.warn("获取本机Ip失败:异常信息:"+e.getMessage());
}
return ip;
}
2.接受微信返回的url
/**
* 获取二维码链接
* @param xmlData
* @return
*/
private String getCodeUrl(String xmlData) {
String resXml = null;
try {
resXml = WxzfUtil.sendPost(WXPayAction.WX_CREATE_ORDER_URL, xmlData);
} catch (UnrecoverableKeyException e1) {
log.error(e1.getMessage());
} catch (KeyManagementException e1) {
log.error(e1.getMessage());
} catch (KeyStoreException e1) {
log.error(e1.getMessage());
} catch (NoSuchAlgorithmException e1) {
log.error(e1.getMessage());
} catch (IOException e1) {
log.error(e1.getMessage());
} String code_url = "";
Map<String, String> map;
try {
map = WxzfUtil.parseXml(resXml);
Object returnCode = map.get("return_code");
if("SUCCESS".equals(returnCode)) {
Object resultCode = map.get("result_code");
if("SUCCESS".equals(resultCode)) {
code_url = map.get("code_url").toString();
}
}
} catch (Exception e) {
log.error(e.getMessage());
return "";
}
return code_url;
}
//将xml数据发送给微信
@SuppressWarnings({ "resource" })
public static String sendPost(String url, String postDataXML)
throws IOException, KeyStoreException, UnrecoverableKeyException,
NoSuchAlgorithmException, KeyManagementException { String result = null; HttpPost httpPost = new HttpPost(url);
HttpClient client = new DefaultHttpClient(); // 得指明使用UTF-8编码，否则到API服务器XML的中文不能被成功识别 StringEntity postEntity = new StringEntity(postDataXML, "UTF-8"); httpPost.addHeader("Content-Type", "text/xml"); httpPost.setEntity(postEntity); try { HttpResponse response = client.execute(httpPost); HttpEntity entity = response.getEntity(); result = EntityUtils.toString(entity, "UTF-8"); } catch (ConnectionPoolTimeoutException e) { // LOG.debug("http get throw ConnectionPoolTimeoutException(wait time out)"); } catch (ConnectTimeoutException e) { // LOG.debug("http get throw ConnectTimeoutException"); } catch (SocketTimeoutException e) { // LOG.debug("http get throw SocketTimeoutException"); } catch (Exception e) { e.printStackTrace(); // LOG.debug("http get throw Exception" ); } finally {
httpPost.abort();
} System.out.println(result); return result; }
3.将url转为二维码显示到页面上
public String payWeChat(String ids,String content,HttpServletResponse response,HttpServletRequest request, ModelMap model){
WebErrors errors = WebErrors.create(request);
try {
OmShopOrder order = orderService.findById(Long.parseLong(ids));
content = this.getImageUrl(order.getSoProductname(), order.getSoId().toString(), order.getSoId().toString(), (int)(order.getSoTotal()*10*10)+"");
MultiFormatWriter multiFormatWriter = new MultiFormatWriter();
Hashtable hints = new Hashtable();
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
BitMatrix bitMatrix = multiFormatWriter.encode(content, BarcodeFormat.QR_CODE, 400, 400,hints);
response.setContentType("image/jpeg");
MatrixToImageWriter.writeToStream(bitMatrix, "jpg", response.getOutputStream());
} catch (Exception e) {
e.printStackTrace();
log.warn("订单已支付，请勿重新支付");
}
return null;
}
4.扫码支付
5.接收微信的异步通知，在这步修改订单的状态
if ("SUCCESS".equals(returnMap.get("return_code"))&&"SUCCESS".equals(returnMap.get("result_code"))) {
//处理你的业务逻辑代码（修改订单支付状态）
}
6.收到异步通知的同时给微信返回指定数据，告知对方已成功处理异步通知
response.setContentType("text/plain;charset=UTF-8");
PrintWriter writer;
try {
writer = response.getWriter();
writer.write("<xml><return_code><![CDATA[SUCCESS]]></return_code><return_msg><![CDATA[OK]]></return_msg></xml>");
writer.flush();
} catch (IOException e) {
e.printStackTrace();
}