https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=7_3&index=1
支付流程步骤：
1）首先调用wx.login方法获取code，通过code获取openid；
2）java后台调用统一下单支付接口（这里会进行第一次签名），用来获取prepay_id；
3）java后台再次调用签名（这里会进行第二次签名），并返回支付需要用使用的参数；
4）小程序前端wx.requestPayment方法发起微信支付；
5）java后台接收来自微信服务器的通知并处理结果。
一、获取openid，
小程序端代码
wx.login({
success: function (res) {
var service_url = 'https://???/???/weixin/api/login?code=' + res.code;//需要将服务器域名添加到小程序的request合法域名中，而且必须是https开头
wx.request({
url: l,
data: {},
method: 'POST',
success: function (res) {
console.log(res);
if (res.data != null && res.data != undefined && res.data != '') {
wx.setStorageSync("openid", res.data.openid);//将获取的openid存到缓存中
}
}
});
}
});
java 后端代码
/**
* 小程序后台登录，向微信平台发送获取access_token请求，并返回openId
* @return 用户凭证
* @throws WeixinException
* @throws IOException
* @throws JsonMappingException
* @throws JsonParseException
*/
@RequestMapping("login")
@ResponseBody
public Map<String, Object> login(String code, HttpServletRequest request) throws WeixinException, JsonParseException, JsonMappingException, IOException {
if (code == null || code.equals("")) {
throw new WeixinException("invalid null, code is null.");
}
Map<String, Object> ret = new HashMap<String, Object>();
//拼接参数
String param = "?grant_type=" + grant_type + "&appid=" + appid + "&secret=" + secret + "&js_code=" + code;
System.out.println("https://api.weixin.qq.com/sns/jscode2session" + param);
//创建请求对象
HttpsClient http = new HttpsClient();
//调用获取access_token接口
Response res = http.get("https://api.weixin.qq.com/sns/jscode2session" + param);
//根据请求结果判定，是否验证成功
JSONObject jsonObj = res.asJSONObject();
if (jsonObj != null) {
Object errcode = jsonObj.get("errcode");
if (errcode != null) {
//返回异常信息
throw new WeixinException(getCause(Integer.parseInt(errcode.toString())));
}
ObjectMapper mapper = new ObjectMapper();
OAuthJsToken oauthJsToken = mapper.readValue(jsonObj.toJSONString(),OAuthJsToken.class);
ret.put("openid", oauthJsToken.getOpenid());
}
return ret;
}二、小程序调用java后端接口，生成最终签名和相关参数小程序端代码：
var that = this;
wx.request({
url: service_url + 'wxPay',
data: { },
method: 'GET',
success: function (res) {
console.log(res);
that.doWxPay(res.data);
}
}java端代码：
/**
* @Description: 发起微信支付
* @param request
*/
public Map<String, Object> wxPay(Integer openid, HttpServletRequest request){
try{
//生成的随机字符串
String nonce_str = StringUtils.getRandomStringByLength(32);
//商品名称
String body = "测试商品名称";
//获取客户端的ip地址
String spbill_create_ip = IpUtil.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);
packageParams.put("mch_id", WxPayConfig.mch_id);
packageParams.put("nonce_str", nonce_str);
packageParams.put("body", body);
packageParams.put("out_trade_no", "123456789");//商户订单号
packageParams.put("total_fee", "1");//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);
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);
String prestr = PayUtil.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 = PayUtil.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>" + "123456789" + "</out_trade_no>"
+ "<spbill_create_ip>" + spbill_create_ip + "</spbill_create_ip>"
+ "<total_fee>" + "1" + "</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 = PayUtil.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
Map map = PayUtil.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 = PayUtil.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;
}
/**
* StringUtils工具类方法
* 获取一定长度的随机字符串，范围0-9，a-z
* @param length：指定字符串长度
* @return 一定长度的随机字符串
*/
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();
}
/**
* IpUtils工具类方法
* 获取真实的ip地址
* @param request
* @return
*/
public static String getIpAddr(HttpServletRequest request) {
String ip = request.getHeader("X-Forwarded-For");
if(StringUtils.isNotEmpty(ip) && !"unKnown".equalsIgnoreCase(ip)){
//多次反向代理后会有多个ip值，第一个ip才是真实ip
int index = ip.indexOf(",");
if(index != -1){
return ip.substring(0,index);
}else{
return ip;
}
}
ip = request.getHeader("X-Real-IP");
if(StringUtils.isNotEmpty(ip) && !"unKnown".equalsIgnoreCase(ip)){
return ip;
}
return request.getRemoteAddr();
}WxPayConfig小程序配置文件
/**
* 小程序微信支付的配置文件
* @author
*/
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 = "https://??/??/weixin/api/wxNotify";
//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 = "https://api.mch.weixin.qq.com/pay/unifiedorder";
}
PayUtils工具类
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.security.SignatureException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.apache.commons.codec.digest.DigestUtils;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
public class PayUtil {
/**
* 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);
}
}
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) {
// TODO Auto-generated catch block
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
*/
public static Map doXMLParse(String strxml) throws Exception {
if(null == strxml || "".equals(strxml)) {
return null;
}
/*============= !!!!注意，修复了微信官方反馈的漏洞，更新于2018-10-16 ===========*/
try {
Map<String, String> data = new HashMap<String, String>();
// TODO 在这里更换
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(List children) {
StringBuffer sb = new StringBuffer();
if(!children.isEmpty()) {
Iterator it = children.iterator();
while(it.hasNext()) {
Element e = (Element) it.next();
String name = e.getName();
String value = e.getTextNormalize();
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());
}
三、小程序端发起最终支付，调用微信付款
doWxPay(param){
//小程序发起微信支付
wx.requestPayment({
timeStamp: param.data.timeStamp,//记住，这边的timeStamp一定要是字符串类型的，不然会报错，我这边在java后端包装成了字符串类型了
nonceStr: param.data.nonceStr,
package: param.data.package,
signType: 'MD5',
paySign: param.data.paySign,
success: function (event) {
// success
console.log(event);
wx.showToast({
title: '支付成功',
icon: 'success',
duration: 2000
});
},
fail: function (error) {
// fail
console.log("支付失败")
console.log(error)
},
complete: function () {
// complete
console.log("pay complete")
}
});
}四、微信服务器通知java后端
/**
* @Description:微信支付
* @return
* @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);
Map map = PayUtil.doXMLParse(notityXml);
String returnCode = (String) map.get("return_code");
if("SUCCESS".equals(returnCode)){
//验证签名是否正确
Map<String, String> validParams = PayUtil.paraFilter(map); //回调验签时需要去除sign和空值参数
String validStr = PayUtil.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 = PayUtil.sign(validStr, WxPayConfig.key, "utf-8").toUpperCase();//拼装生成服务器端验证的签名
//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"))){
/**此处添加自己的业务逻辑代码start**/
/**此处添加自己的业务逻辑代码end**/
//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();
}
源码:链接：https://pan.baidu.com/s/15wAQATvENTMXb1LERsOwQA
提取码：yxac