先定义一个配置类：
/**
* 微信支付配置
* @author USER
*
*/
public class WxPayConfig {
// 小程序appid
public static final String appid = "";
// 微信支付的商户id
public static final String mch_id = "";
// 微信支付的商户密钥
public static final String key = "";
// 支付成功后的服务器回调url
public static final String notify_url = "";
// 签名方式，固定值
public static final String SIGNTYPE = "MD5";
// 交易类型，小程序支付的固定值为JSAPI
public static final String TRADETYPE = "JSAPI";
// 微信统一下单接口地址
public static final String pay_url = "";
}
Controller层，因为博主懒，所以没有拆分Service层
@RestController
public class WxPayController {
@Autowired
private PayInfoService payInfoService;
@RequestMapping(value = "/wxPay", method = RequestMethod.POST)
public Map<String, Object> wxPay(String openid, String ownOrderNo, HttpServletRequest request) {
PayInfo payinfo = payInfoService.findByOwnOrderNo(ownOrderNo);
if (payinfo == null) {
return null;
}
payinfo.setOpenid(openid);
payInfoService.save(payinfo);
String pay = Integer.toString(payinfo.getPayable());
try {
// 生成的随机字符串
String nonce_str = StringUtils.getRandomStringByLength(32);
// 商品名称
String body = "测试停车费用";
// 获取客户端的ip地址
String spbill_create_ip = IpUtils.getIpAddr(request);
// 组装参数，用户生成统一下单接口的签名
Map<String, String> packageParams = new HashMap<String, String>();
packageParams.put("appid", WxPayConfig.appid);// 停车场appid
packageParams.put("mch_id", WxPayConfig.mch_id);// 商户id
packageParams.put("nonce_str", nonce_str);// 32位随机字符串
packageParams.put("body", body);// 商品名称
packageParams.put("out_trade_no", ownOrderNo);// 商户订单号
packageParams.put("total_fee", pay);// 支付金额，这边需要转成字符串类型，否则后面的签名会失败
packageParams.put("spbill_create_ip", spbill_create_ip);// 客户端的ip地址
packageParams.put("notify_url", WxPayConfig.notify_url);// 支付成功后的回调地址
packageParams.put("trade_type", WxPayConfig.TRADETYPE);// 支付方式
packageParams.put("openid", openid);// 微信openid
String prestr = PayUtils.createLinkString(packageParams); // 把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串
// MD5运算生成签名，这里是第一次签名，用于调用统一下单接口
String mysign = PayUtils.sign(prestr, WxPayConfig.key, "utf-8").toUpperCase();
// 拼接统一下单接口使用的xml数据，要将上一步生成的签名一起拼接进去
String xml = "<xml>" + "<appid>" + WxPayConfig.appid + "</appid>" + "<body><![CDATA[" + body + "]]></body>"
+ "<mch_id>" + WxPayConfig.mch_id + "</mch_id>" + "<nonce_str>" + nonce_str + "</nonce_str>"
+ "<notify_url>" + WxPayConfig.notify_url + "</notify_url>" + "<openid>" + openid + "</openid>"
+ "<out_trade_no>" + ownOrderNo + "</out_trade_no>" + "<spbill_create_ip>" + spbill_create_ip
+ "</spbill_create_ip>" + "<total_fee>" + pay + "</total_fee>" + "<trade_type>"
+ WxPayConfig.TRADETYPE + "</trade_type>" + "<sign>" + mysign + "</sign>" + "</xml>";
System.out.println("调试模式_统一下单接口 请求XML数据：" + xml);
// 调用统一下单接口，并接受返回的结果
String result = PayUtils.httpRequest(WxPayConfig.pay_url, "POST", xml);
System.out.println("调试模式_统一下单接口 返回XML数据：" + result);
// 将解析结果存储在HashMap中
@SuppressWarnings("rawtypes")
Map map = PayUtils.doXMLParse(result);
String return_code = (String) map.get("return_code");// 返回状态码
Map<String, Object> response = new HashMap<String, Object>();// 返回给小程序端需要的参数
if (return_code.equals("SUCCESS")) {
String prepay_id = (String) map.get("prepay_id");// 返回的预付单信息
response.put("nonceStr", nonce_str);
response.put("package", "prepay_id=" + prepay_id);
Long timeStamp = System.currentTimeMillis() / 1000;
response.put("timeStamp", timeStamp + "");// 这边要将返回的时间戳转化成字符串，不然小程序端调用wx.requestPayment方法会报签名错误
// 拼接签名需要的参数
String stringSignTemp = "appId=" + WxPayConfig.appid + "&nonceStr=" + nonce_str + "&package=prepay_id="
+ prepay_id + "&signType=MD5&timeStamp=" + timeStamp;
// 再次签名，这个签名用于小程序端调用wx.requesetPayment方法
String paySign = PayUtils.sign(stringSignTemp, WxPayConfig.key, "utf-8").toUpperCase();
response.put("paySign", paySign);
}
response.put("appid", WxPayConfig.appid);
return response;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 微信服务器通知java后端
*
* @param request
* @param response
* @throws Exception
*/
@RequestMapping(value = "/wxNotify")
@ResponseBody
public void wxNotify(HttpServletRequest request, HttpServletResponse response) throws Exception {
BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream) request.getInputStream()));
String line = null;
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
sb.append(line);
}
br.close();
// sb为微信返回的xml
String notityXml = sb.toString();
String resXml = "";
System.out.println("接收到的报文：" + notityXml);
@SuppressWarnings("rawtypes")
Map map = PayUtils.doXMLParse(notityXml);
String returnCode = (String) map.get("return_code");
if ("SUCCESS".equals(returnCode)) {
// 验证签名是否正确
@SuppressWarnings("unchecked")
Map<String, String> validParams = PayUtils.paraFilter(map); // 回调验签时需要去除sign和空值参数
String validStr = PayUtils.createLinkString(validParams);// 把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串
String sign = PayUtils.sign(validStr, WxPayConfig.key, "utf-8").toUpperCase();// 拼装生成服务器端验证的签名
String ownOrderNo = request.getParameter("ownOrderNo");//获取订单号
PayInfo payinfo = payInfoService.findByOwnOrderNo(ownOrderNo);
Integer payable = payinfo.getPayable();
// 根据微信官网的介绍，此处不仅对回调的参数进行验签，还需要对返回的金额与系统订单的金额进行比对等
if (sign.equals(map.get("sign"))) {
//返回的金额与系统订单的金额进行比对
if (payable.toString()==request.getParameter("payable")) {
return;
}
// 通知微信服务器已经支付成功
resXml = "<xml>" + "<return_code><![CDATA[SUCCESS]]></return_code>"
+ "<return_msg><![CDATA[OK]]></return_msg>" + "</xml> ";
}
} else {
resXml = "<xml>" + "<return_code><![CDATA[FAIL]]></return_code>"
+ "<return_msg><![CDATA[报文为空]]></return_msg>" + "</xml> ";
}
System.out.println(resXml);
System.out.println("微信支付回调数据结束");
BufferedOutputStream out = new BufferedOutputStream(response.getOutputStream());
out.write(resXml.getBytes());
out.flush();
out.close();
}
}
下面是涉及到的Util包：
public class PayUtils {
/**
* 签名字符串
*
* @param text需要签名的字符串
* @param key 密钥
* @param input_charset编码格式
* @return 签名结果
*/
public static String sign(String text, String key, String input_charset) {
text = text + "&key=" + key;
return DigestUtils.md5Hex(getContentBytes(text, input_charset));
}
/**
* 签名字符串
*
* @param text需要签名的字符串
* @param sign 签名结果
* @param key密钥
* @param input_charset 编码格式
* @return 签名结果
*/
public static boolean verify(String text, String sign, String key, String input_charset) {
text = text + key;
String mysign = DigestUtils.md5Hex(getContentBytes(text, input_charset));
if (mysign.equals(sign)) {
return true;
} else {
return false;
}
}
/**
* @param content
* @param charset
* @return
* @throws SignatureException
* @throws UnsupportedEncodingException
*/
public static byte[] getContentBytes(String content, String charset) {
if (charset == null || "".equals(charset)) {
return content.getBytes();
}
try {
return content.getBytes(charset);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("MD5签名过程中出现错误,指定的编码集不对,您目前指定的编码集是:" + charset);
}
}
@SuppressWarnings("unused")
private static boolean isValidChar(char ch) {
if ((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z'))
return true;
if ((ch >= 0x4e00 && ch <= 0x7fff) || (ch >= 0x8000 && ch <= 0x952f))
return true;// 简体中文汉字编码
return false;
}
/**
* 除去数组中的空值和签名参数
*
* @param sArray 签名参数组
* @return 去掉空值与签名参数后的新签名参数组
*/
public static Map<String, String> paraFilter(Map<String, String> sArray) {
Map<String, String> result = new HashMap<String, String>();
if (sArray == null || sArray.size() <= 0) {
return result;
}
for (String key : sArray.keySet()) {
String value = sArray.get(key);
if (value == null || value.equals("") || key.equalsIgnoreCase("sign")
|| key.equalsIgnoreCase("sign_type")) {
continue;
}
result.put(key, value);
}
return result;
}
/**
* 把数组所有元素排序，并按照“参数=参数值”的模式用“&”字符拼接成字符串
*
* @param params 需要排序并参与字符拼接的参数组
* @return 拼接后字符串
*/
public static String createLinkString(Map<String, String> params) {
List<String> keys = new ArrayList<String>(params.keySet());
Collections.sort(keys);
String prestr = "";
for (int i = 0; i < keys.size(); i++) {
String key = keys.get(i);
String value = params.get(key);
if (i == keys.size() - 1) {// 拼接时，不包括最后一个&字符
prestr = prestr + key + "=" + value;
} else {
prestr = prestr + key + "=" + value + "&";
}
}
return prestr;
}
/**
*
* @param requestUrl请求地址
* @param requestMethod请求方法
* @param outputStr参数
*/
public static String httpRequest(String requestUrl, String requestMethod, String outputStr) {
// 创建SSLContext
StringBuffer buffer = null;
try {
URL url = new URL(requestUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod(requestMethod);
conn.setDoOutput(true);
conn.setDoInput(true);
conn.connect();
// 往服务器端写内容
if (null != outputStr) {
OutputStream os = conn.getOutputStream();
os.write(outputStr.getBytes("utf-8"));
os.close();
}
// 读取服务器端返回的内容
InputStream is = conn.getInputStream();
InputStreamReader isr = new InputStreamReader(is, "utf-8");
BufferedReader br = new BufferedReader(isr);
buffer = new StringBuffer();
String line = null;
while ((line = br.readLine()) != null) {
buffer.append(line);
}
br.close();
} catch (Exception e) {
e.printStackTrace();
}
return buffer.toString();
}
public static String urlEncodeUTF8(String source) {
String result = source;
try {
result = java.net.URLEncoder.encode(source, "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return result;
}
/**
* 解析xml,返回第一级元素键值对。如果第一级元素有子节点，则此节点的值是子节点的xml数据。
*
* @param strxml
* @return
* @throws JDOMException
* @throws IOException
*/
@SuppressWarnings("rawtypes")
public static Map doXMLParse(String strxml) throws Exception {
if (null == strxml || "".equals(strxml)) {
return null;
}
try {
Map<String, String> data = new HashMap<String, String>();
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
documentBuilderFactory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
documentBuilderFactory.setFeature("http://xml.org/sax/features/external-general-entities", false);
documentBuilderFactory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
documentBuilderFactory.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
documentBuilderFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
documentBuilderFactory.setXIncludeAware(false);
documentBuilderFactory.setExpandEntityReferences(false);
InputStream stream = new ByteArrayInputStream(strxml.getBytes("UTF-8"));
org.w3c.dom.Document doc = documentBuilderFactory.newDocumentBuilder().parse(stream);
doc.getDocumentElement().normalize();
NodeList nodeList = doc.getDocumentElement().getChildNodes();
for (int idx = 0; idx < nodeList.getLength(); ++idx) {
Node node = nodeList.item(idx);
if (node.getNodeType() == Node.ELEMENT_NODE) {
org.w3c.dom.Element element = (org.w3c.dom.Element) node;
data.put(element.getNodeName(), element.getTextContent());
}
}
try {
stream.close();
} catch (Exception ex) {
// do nothing
}
return data;
} catch (Exception ex) {
throw ex;
}
}
/**
* 获取子结点的xml
*
* @param children
* @return String
*/
public static String getChildrenText(@SuppressWarnings("rawtypes") List children) {
StringBuffer sb = new StringBuffer();
if (!children.isEmpty()) {
@SuppressWarnings("rawtypes")
Iterator it = children.iterator();
while (it.hasNext()) {
Element e = (Element) it.next();
String name = e.getName();
String value = e.getTextNormalize();
@SuppressWarnings("rawtypes")
List list = e.getChildren();
sb.append("<" + name + ">");
if (!list.isEmpty()) {
sb.append(getChildrenText(list));
}
sb.append(value);
sb.append("</" + name + ">");
}
}
return sb.toString();
}
public static InputStream String2Inputstream(String str) {
return new ByteArrayInputStream(str.getBytes());
}
}
至此，整个支付流程都已实现。