一、流程

1. 需要在官方申请接入微信支付 微信支付商户申请地址（申请需要营业执照，个人无法申请）
2. 申请完成后需要等待 1-3 天审核，审核通过后需要在 微信商户平台 获取 appID（公众号ID），mchID （商户ID）、key （在微信支付中设置的私钥）、安全证书

二、在springboot整合微信支付

1. 导入所需的依赖

<!-- 生成二维码工具 -->
<dependency><groupId>com.google.zxing</groupId><artifactId>core</artifactId><version>3.2.1</version></dependency><dependency><groupId>com.google.zxing</groupId><artifactId>javase</artifactId><version>3.2.0</version></dependency><!-- 微信支付所需sdk --><dependency><groupId>com.github.wxpay</groupId><artifactId>wxpay-sdk</artifactId><version>0.0.3</version>
</dependency>

2. yml文件配置相关信息

# 服务器域名地址
server:service-domain: 域名地址信息
#微信app支付
pay:wxpay:app:appID: 公众号idmchID: 商户idkey: 设置的私钥certPath: static/cert/wxpay/apiclient_cert.p12 # 从微信商户平台下载的安全证书存放的路径、我放在resources下面,切记一定要看看target目录下的class文件下有没有打包apiclient_cert.p12文件payNotifyUrl: ${server.service-domain}/wxPay/callback # 微信支付成功的异步通知接口

3. 读取配置文件信息

import com.github.wxpay.sdk.WXPayConfig;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
import java.io.InputStream;@Component
@ConfigurationProperties(prefix = "pay.wxpay.app")
public class MyWXPayConfig implements WXPayConfig {/*** appID*/private String appID;/*** 商户号*/private String mchID;/*** API 密钥*/private String key;/*** API证书绝对路径 (本项目放在了 resources/cert/wxpay/apiclient_cert.p12")*/private String certPath;/*** HTTP(S) 连接超时时间，单位毫秒*/private int httpConnectTimeoutMs = 8000;/*** HTTP(S) 读数据超时时间，单位毫秒*/private int httpReadTimeoutMs = 10000;/*** 微信支付异步通知地址*/private String payNotifyUrl;/*** 微信退款异步通知地址*/private String refundNotifyUrl;/*** 统一下单url*/private static final String UNIFIED_ORDER_URL = "https://api.mch.weixin.qq.com/pay/unifiedorder";/*** 获取商户证书内容（这里证书需要到微信商户平台进行下载）** @return 商户证书内容*/@Overridepublic InputStream getCertStream() {InputStream certStream  =getClass().getClassLoader().getResourceAsStream(certPath);return certStream;}// ... 省略 getter 和 setter 方法

4. 微信支付用到的 utils 类

解析 xml 的工具类

import org.w3c.dom.Document;
import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;public final class WXPayXmlUtil {public static DocumentBuilder newDocumentBuilder() throws ParserConfigurationException {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);return documentBuilderFactory.newDocumentBuilder();}public static Document newDocument() throws ParserConfigurationException {return newDocumentBuilder().newDocument();}
}

import com.github.wxpay.sdk.WXPayUtil;
import com.stylefeng.guns.modular.system.util.CommonUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Document;
import org.w3c.dom.Element;import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.StringWriter;
import java.util.*;/*** @Author qjp*/
public class WXPayUtils {/*** XML格式字符串转换为Map** @param strXML XML字符串* @return XML数据转换后的Map* @throws Exception*/public static Map<String, String> xmlToMap(String strXML) throws Exception {try {Map<String, String> data = new HashMap<String, String>();DocumentBuilder documentBuilder = WXPayXmlUtil.newDocumentBuilder();InputStream stream = new ByteArrayInputStream(strXML.getBytes("UTF-8"));org.w3c.dom.Document doc = documentBuilder.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) {WXPayUtils.getLogger().warn("Invalid XML, can not convert to map. Error message: {}. XML content: {}", ex.getMessage(), strXML);throw ex;}}/*** 将Map转换为XML格式的字符串** @param data Map类型数据* @return XML格式的字符串* @throws Exception*/public static String mapToXml(Map<String, String> data) throws Exception {Document document = WXPayXmlUtil.newDocument();Element root = document.createElement("xml");document.appendChild(root);for (String key: data.keySet()) {String value = data.get(key);if (value == null) {value = "";}value = value.trim();Element filed = document.createElement(key);filed.appendChild(document.createTextNode(value));root.appendChild(filed);}TransformerFactory tf = TransformerFactory.newInstance();Transformer transformer = tf.newTransformer();DOMSource source = new DOMSource(document);transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");transformer.setOutputProperty(OutputKeys.INDENT, "yes");StringWriter writer = new StringWriter();StreamResult result = new StreamResult(writer);transformer.transform(source, result);String output = writer.getBuffer().toString(); //.replaceAll("\n|\r", "");try {writer.close();}catch (Exception ex) {}return output;}/*** 生成微信支付sign*/public static String createSign(SortedMap<String, String> params, String key){StringBuilder sb = new StringBuilder();Set<Map.Entry<String, String>> es = params.entrySet();Iterator<Map.Entry<String, String>> it = es.iterator();while(it.hasNext()){Map.Entry<String, String> entry = it.next();String k = entry.getKey();String v = entry.getValue();if(null != v && !"".equals(v) && !"sign".equals(k) && !"key".equals(k)){sb.append(k + "=" + v + "&");}}sb.append("key=").append(key);String sign = CommonUtils.MD5(sb.toString()).toUpperCase();return sign;}/*** 校验签名* @param params* @param key* @return*/public static Boolean isCorrectSign(SortedMap<String, String> params, String key){String sign = createSign(params, key);String wxPaySign = params.get("sign").toUpperCase();return  wxPaySign.equals(sign);}/*** 获取有序map* @param map*/public static SortedMap<String, String> getSortedMap(Map<String, String> map){SortedMap<String, String> sortedMap = new TreeMap<>();Iterator<String> it = map.keySet().iterator();while(it.hasNext()){String key = it.next();String value = map.get(key);String temp = "";if(null != value){temp = value.trim();}sortedMap.put(key, value);}return sortedMap;}/*** 日志* @return*/public static Logger getLogger() {Logger logger = LoggerFactory.getLogger("wxpay java sdk");return logger;}/*** 获取当前时间戳，单位秒* @return*/public static long getCurrentTimestamp() {return System.currentTimeMillis()/1000;}/*** 获取当前时间戳，单位毫秒* @return*/public static long getCurrentTimestampMs() {return System.currentTimeMillis();}/*** 生成UUID(用来表示一笔订单)* @return*/public static String generateUUID(){String uuid = UUID.randomUUID().toString().replaceAll("-","").substring(0,32);return uuid;}
}

请求微信支付api接口

public class HttpClientUtil {public static String doPost(String url, String data, int timeOut){CloseableHttpClient httpClient = HttpClients.createDefault();// 超时设置RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(timeOut) // 连接超时.setConnectionRequestTimeout(timeOut) // 请求超时.setSocketTimeout(timeOut).setRedirectsEnabled(true) // 允许自动重定向.build();HttpPost httpPost = new HttpPost(url);httpPost.setConfig(requestConfig);httpPost.addHeader("Content-Type","text/html; chartset=UTF-8");if(data != null && data instanceof String){ // 使用字符串传参StringEntity stringEntity = new StringEntity(data,"UTF-8");httpPost.setEntity(stringEntity);}try {CloseableHttpResponse httpResponse = httpClient.execute(httpPost);HttpEntity httpEntity = httpResponse.getEntity();if(httpResponse.getStatusLine().getStatusCode() == 200){String result = EntityUtils.toString(httpEntity);return result;}} catch (Exception e){e.printStackTrace();}  finally {try {httpClient.close();} catch (IOException e) {e.printStackTrace();}}return null;}
}

5. service层处理微信支付请求

@Service
public class WxPayServiceImpl implements WxPayService { @Autowiredprivate MyWXPayConfig wxPayAppConfig;@Overridepublic String save(String orderNo, double amount, String body){Integer uid = ShiroKit.getUser().getId();// 1. 生成订单// 订单号，流水号，金额，付款状态，创建时间String product_id = WXPayUtils.generateUUID();Pay pay = new Pay();pay.setTradeNo(product_id);pay.setOutTradeNo(orderNo);pay.setBody(body);pay.setPaystatus(1);pay.setUid(uid);pay.setTotalAmount(amount);pay.setGmtCreate(new Date());pay.setTradeStatus("0");pay.setAppId(wxPayAppConfig.getAppID());// 生成预支付订单，保存到数据库payMapper.insert(pay);// 调用统一下单方法，返回 codeUrl 地址String codeUrl = unifiedOrder(product_id,orderNo,amount,body);return codeUrl;}private String unifiedOrder(String product_id, String orderNo, double amount, String body){// 生成签名try{SortedMap<String, String> params = new TreeMap<>();params.put("appid",wxPayAppConfig.getAppID());params.put("mch_id",wxPayAppConfig.getMchID());params.put("nonce_str", CommonUtils.generateUUID());params.put("body",body);                      // 商品描述params.put("out_trade_no",orderNo);           // 商户订单号params.put("total_fee",String.valueOf((int)(amount*100)));              // 标价金额（单位为分）params.put("spbill_create_ip", "外网可以访问的 ip 地址");    // 终端IPparams.put("notify_url", wxPayAppConfig.getPayNotifyUrl());    // 异步接收微信支付结果通知的回调地址params.put("trade_type","NATIVE");                  // 交易类型params.put("product_id",product_id);                // 微信支付要求NATIVE支付，此参数必填// sign 签名String sign = WXPayUtils.createSign(params, wxPayAppConfig.getKey());params.put("sign",sign);System.out.println(sign);// map转xmlString payXml = WXPayUtils.mapToXml(params);System.out.println(payXml);// 统一下单String s = HttpClientUtil.doPost(wxPayAppConfig.getUnifiedOrderUrl(), payXml, 10000);if(null == s){return null;}Map<String, String> unifiedOrderMap = WXPayUtils.xmlToMap(s);System.out.println(unifiedOrderMap.toString());if(unifiedOrderMap != null){// 前台添加定时器，进行轮询操作，直到支付完毕return unifiedOrderMap.get("code_url");}} catch (Exception e){e.printStackTrace();}return null;}}

6. 生成二维码和回调函数

@RestController
@RequestMapping("/wxPay")
public class WxPayController{@Autowiredprivate WxPayService wxPayService;@Autowiredprivate MyWXPayConfig wxPayConfig;/*** 微信支付 生成二维码** @param money* @return*/@GetMapping("/pay")public void wxPay(String money, HttpServletResponse response){String body = "套餐描述";Double amount = 0.01;SimpleDateFormat date = new SimpleDateFormat("yyyyMMddHHmmss");String orderNo = date.format(new Date()) + WXPayUtils.getCurrentTimestampMs();String url_code = wxPayService.save(orderNo, amount, body);if(url_code == null){throw new NullPointerException();}try {// 生成二维码配置Map<EncodeHintType, Object> hints = new HashMap<>();// 设置纠错等级hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 编码类型hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");BitMatrix bitMatrix = new MultiFormatWriter().encode(url_code, BarcodeFormat.QR_CODE, 400, 400, hints);OutputStream outputStream = response.getOutputStream();MatrixToImageWriter.writeToStream(bitMatrix, "png", outputStream);} catch (Exception e){e.printStackTrace();}}/*** 微信支付回调接口*/@RequestMapping("/callback")public void OrderCallBack(HttpServletRequest request,HttpServletResponse response){InputStream inputStream = null;try {inputStream = request.getInputStream();// BufferedReader是包装设计模式，性能更高BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));StringBuffer stringBuffer = new StringBuffer();String line;while ((line = bufferedReader.readLine()) != null){stringBuffer.append(line);}bufferedReader.close();inputStream.close();Map<String,String> callBackMap = WXPayUtils.xmlToMap(stringBuffer.toString());System.out.println(callBackMap.toString());SortedMap<String, String> sortedMap = WXPayUtils.getSortedMap(callBackMap);// 校验签名是否正确if(WXPayUtils.isCorrectSign(sortedMap, wxPayConfig.getKey())){System.out.println("签名校验成功！");// 更新订单状态if("SUCCESS".equals(sortedMap.get("result_code"))){String outTradeNo = sortedMap.get("out_trade_no"); // 流水号String totalFee = sortedMap.get("total_fee"); // 交易金额if(wxPayService.callBackPayUpdate(outTradeNo,totalFee)){    // 通知微信订单处理成功response.setContentType("text/xml");response.getWriter().println("success");return;}}// 未成功，就都处理为失败订单response.setContentType("text/html");response.getWriter().println("fail");}} catch (IOException e) {e.printStackTrace();} catch (Exception e){e.printStackTrace();}}

注意：微信支付在统一下单方法填写的 ip地址 需要外网才能访问成功，如：localhost，127.0.0.1 这些地址都会导致下单失败