调用微信公众支付的统一下单APIAPI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
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0
通知地址：微信支付成功或失败回调给系统的地址
签名：
import java.io.Serializable;
public class PayInfo implements Serializable{
private static final long serialVersionUID = 5637164279924222380L;
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：
/**
* 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 md5 = MessageDigest.getInstance("MD5");
md5.reset();
md5.update(signTemp.getBytes("UTF-8"));
String sign = CommonUtil.byteToStr(md5.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
/**
* 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 = 0; 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 = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
char[] tempArr = new char[2];
tempArr[0] = Digit[(bytes >>> 4) & 0X0F];
tempArr[1] = Digit[bytes & 0X0F];
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 = 0; i < ipAddr.length; i++) {
if (i > 0) {
ipAddrStr += ".";
}
ipAddrStr += ipAddr[i] & 0xFF;
}
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。
PayInfo pi = pu.createPayInfo(bo,"10.204.3.32","22"); String sign = pu.getSign(pi); pi.setSign(sign);
对象转XML
/**
* 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
@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
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方法
private static StringBuffer httpsRequest(String requestUrl, String requestMethod, String output)
throws NoSuchAlgorithmException, NoSuchProviderException, KeyManagementException, MalformedURLException,
IOException, ProtocolException, UnsupportedEncodingException {
URL url = new URL(requestUrl);
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false);
connection.setRequestMethod(requestMethod);
if (null != output) {
OutputStream outputStream = connection.getOutputStream();
outputStream.write(output.getBytes("UTF-8"));
outputStream.close();
}
// 从输入流读取返回内容
InputStream inputStream = connection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String str = null;
StringBuffer buffer = new StringBuffer();
while ((str = bufferedReader.readLine()) != null) {
buffer.append(str);
}
bufferedReader.close();
inputStreamReader.close();
inputStream.close();
inputStream = null;
connection.disconnect();
return buffer;
} }上面获取到的Map如果成功的话，里面就会有
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。补充1这节课的支付需要它。
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