微信小程式支付+java後臺程式碼

阿新 • • 發佈：2020-11-17

一、java後臺

　1、maven引入

<!--微信支付-->
<dependency>
   <groupId>com.github.wxpay</groupId>
   <artifactId>wxpay-sdk</artifactId>
   <version>0.0.3</version>
</dependency>

<dependency>
   <groupId>org.jdom</groupId>
   <artifactId>jdom</artifactId>
   <version>2.0.2</version>
</dependency>

　2、java程式碼

　　　　WxUtils類

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClients;

import org.jdom2.Document;
import org.jdom2.Element;
import 
 org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpServletRequest;
import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
 
import java.util.*;
@Component
public class WxUtils {

    /**
     * 執行 POST 方法的 HTTP 請求
     *
     * @param url
     * @param parameters
     * @return
     * @throws IOException
     */
    public String executeHttpPost(String url, SortedMap<String, Object> parameters) throws IOException {
        HttpClient client = HttpClients.createDefault();
        HttpPost request = new HttpPost(url);
        request.setHeader("Content-type", "application/xml");
        request.setHeader("Accept", "application/xml");
        request.setEntity(new StringEntity(transferMapToXml(parameters), "UTF-8"));
        HttpResponse response = client.execute(request);
        return readResponse(response);
    }


    /**
     * 第一次簽名
     *
     * @param parameters 資料為伺服器生成，下單時必須的欄位排序簽名
     * @param key
     * @return
     */
    public String createSign(SortedMap<String, Object> parameters, String key) {
        StringBuffer sb = new StringBuffer();
        Set es = parameters.entrySet();//所有參與傳參的引數按照accsii排序（升序）
        Iterator it = es.iterator();
        while (it.hasNext()) {
            Map.Entry entry = (Map.Entry) it.next();
            String k = (String) entry.getKey();
            Object v = entry.getValue();
            if (null != v && !"".equals(v)
                    && !"sign".equals(k) && !"key".equals(k)) {
                sb.append(k + "=" + v + "&");
            }
        }
        sb.append("key=" + key);
        return encodeMD5(sb.toString());
    }

    /**
     * 第二次簽名
     *
     * @param result 資料為微信返回給伺服器的資料（XML 的 String），再次簽名後傳回給客戶端（APP）使用
     * @param key    金鑰
     * @return
     * @throws IOException
     */
    public Map createSign2(String result, String key) throws IOException {
        SortedMap<String, Object> map = new TreeMap<>(transferXmlToMap(result));
        Map app = new HashMap();
        System.out.println(map);
        app.put("appId", map.get("appid"));
        app.put("nonceStr", map.get("nonce_str"));
        app.put("package", "prepay_id="+map.get("prepay_id"));
        app.put("signType", "MD5");
        app.put("timeStamp",String.valueOf(new Date().getTime() / 1000) );  // 時間為秒，JDK 生成的是毫秒，故除以 1000
        app.put("sign", createSign(new TreeMap<>(app), key));
        return app;
    }

    /**
     * 驗證簽名是否正確
     *
     * @return boolean
     * @throws Exception
     */
    public boolean checkSign(SortedMap<String, Object> parameters, String key) throws Exception {
        String signWx = parameters.get("sign").toString();
        if (signWx == null) return false;
        parameters.remove("sign"); // 需要去掉原 map 中包含的 sign 欄位再進行簽名
        String signMe = createSign(parameters, key);
        return signWx.equals(signMe);
    }

    /**
     * 讀取 request body 內容作為字串
     *
     * @param request
     * @return
     * @throws IOException
     */
    public String readRequest(HttpServletRequest request) throws IOException {
        InputStream inputStream;
        StringBuffer sb = new StringBuffer();
        inputStream = request.getInputStream();
        String str;
        BufferedReader in = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
        while ((str = in.readLine()) != null) {
            sb.append(str);
        }
        in.close();
        inputStream.close();
        return sb.toString();
    }

    /**
     * 讀取 response body 內容為字串
     */
    public String readResponse(HttpResponse response) throws IOException {
        BufferedReader in = new BufferedReader(
                new InputStreamReader(response.getEntity().getContent()));
        String result = new String();
        String line;
        while ((line = in.readLine()) != null) {
            result += line;
        }
        return result;
    }

    /**
     * 將 Map 轉化為 XML
     *
     * @param map
     * @return
     */
    public String transferMapToXml(SortedMap<String, Object> map) {
        StringBuffer sb = new StringBuffer();
        sb.append("<xml>");
        for (String key : map.keySet()) {
            sb.append("<").append(key).append(">")
                    .append(map.get(key))
                    .append("</").append(key).append(">");
        }
        return sb.append("</xml>").toString();
    }

    /**
     * 將 XML 轉化為 map
     *
     * @param strxml
     * @return
     * @throws org.jdom2.JDOMException
     * @throws IOException
     */
    public Map transferXmlToMap(String strxml) throws IOException {
        strxml = strxml.replaceFirst("encoding=\".*\"", "encoding=\"UTF-8\"");
        if (null == strxml || "".equals(strxml)) {
            return null;
        }
        Map m = new HashMap();
        InputStream in = new ByteArrayInputStream(strxml.getBytes("UTF-8"));
        SAXBuilder builder = new SAXBuilder();
        Document doc = null;
        try {
            doc = builder.build(in);
        } catch (JDOMException e) {
            throw new IOException(e.getMessage()); // 統一轉化為 IO 異常輸出
        }
        // 解析 DOM
        Element root = doc.getRootElement();
        List list = root.getChildren();
        Iterator it = list.iterator();
        while (it.hasNext()) {
            Element e = (Element) it.next();
            String k = e.getName();
            String v = "";
            List children = e.getChildren();
            if (children.isEmpty()) {
                v = e.getTextNormalize();
            } else {
                v = getChildrenText(children);
            }
            m.put(k, v);
        }
        //關閉流
        in.close();
        return m;
    }

    // 輔助 transferXmlToMap 方法遞迴提取子節點資料
    private String getChildrenText(List<Element> children) {
        StringBuffer sb = new StringBuffer();
        if (!children.isEmpty()) {
            Iterator<Element> it = children.iterator();
            while (it.hasNext()) {
                Element e = (Element) it.next();
                String name = e.getName();
                String value = e.getTextNormalize();
                List<Element> list = e.getChildren();
                sb.append("<" + name + ">");
                if (!list.isEmpty()) {
                    sb.append(getChildrenText(list));
                }
                sb.append(value);
                sb.append("</" + name + ">");
            }
        }
        return sb.toString();
    }


    /**
     * 生成 32 位隨機字串，包含：數字、字母大小寫
     *
     * @return
     */
    public  String gen32RandomString() {
        char[] dict = {'1', '2', '3', '4', '5', '6', '7', '8', '9', '0',
                'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
                'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
        StringBuffer sb = new StringBuffer();
        Random random = new Random();
        for (int i = 0; i < 32; i++) {
            sb.append(String.valueOf(dict[(int) (Math.random() * 36)]));
        }
        return sb.toString();
    }

    /**
     * MD5 簽名
     *
     * @param str
     * @return 簽名後的字串資訊
     */
    public String encodeMD5(String str) {
        try {
            MessageDigest messageDigest = MessageDigest.getInstance("MD5");
            byte[] inputByteArray = (str).getBytes();
            messageDigest.update(inputByteArray);
            byte[] resultByteArray = messageDigest.digest();
            return byteArrayToHex(resultByteArray);
        } catch (NoSuchAlgorithmException e) {
            return null;
        }
    }

    // 輔助 encodeMD5 方法實現
    private String byteArrayToHex(byte[] byteArray) {
        char[] hexDigits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        char[] resultCharArray = new char[byteArray.length * 2];
        int index = 0;
        for (byte b : byteArray) {
            resultCharArray[index++] = hexDigits[b >>> 4 & 0xf];
            resultCharArray[index++] = hexDigits[b & 0xf];
        }
        // 字元陣列組合成字串返回
        return new String(resultCharArray);
    }
}

統一下單介面

  //統一下單介面
    public Map createOrder(@PathVariable String ids, @CurrentPerson CurPersonInfo currentPerson) throws IOException {
       
        SortedMap<String, Object> parameters = new TreeMap<String, Object>();
        parameters.put("appid", APPID);
        parameters.put("mch_id", MCH_ID);
        parameters.put("device_info", "WEB"); // 預設 "WEB"
        parameters.put("body", body);
        parameters.put("nonce_str", wxUtils.gen32RandomString()); // 32 位隨機字串
        parameters.put("notify_url", notifyUrl);
        parameters.put("out_trade_no", ids);
        parameters.put("sign_type", "MD5");
        parameters.put("total_fee", 1); // 測試時，將支付金額設定為 1 分錢
        parameters.put("spbill_create_ip", "127.0.0.1");
        parameters.put("trade_type", "JSAPI");
        System.out.println(currentPerson.getOpenId());
        parameters.put("openid", currentPerson.getOpenId());
        parameters.put("sign", wxUtils.createSign(parameters, KEY)); // sign 必須在最後

        System.out.println(parameters);
        String result = wxUtils.executeHttpPost(placeUrl, parameters); // 執行 HTTP 請求，獲取接收的字串（一段 XML）
        Map resultInfo=wxUtils.createSign2(result, KEY);
        System.out.println(resultInfo);
        return resultInfo;
  
    }

回撥介面

 @RequestMapping(value = "/callBack")
    public String callBack(HttpServletRequest request, HttpServletResponse response) throws Exception {
        // 預先設定返回的 response 型別為 xml
        response.setHeader("Content-type", "application/xml");
        // 讀取引數，解析Xml為map
        Map<String, String> map = wxUtils.transferXmlToMap(wxUtils.readRequest(request));
        // 轉換為有序 map，判斷簽名是否正確
        boolean isSignSuccess = wxUtils.checkSign(new TreeMap<String, Object>(map), KEY);
        if (isSignSuccess) {
            // 簽名校驗成功，說明是微信伺服器發出的資料
               業務程式碼
            return success();
        } else {
            // 簽名校驗失敗（可能不是微信伺服器發出的資料）
            return fail();
        }
    }

    String fail() {
        return "<xml>\n" +
                "  <return_code><![CDATA[FAIL]]></return_code>\n" +
                "  <return_msg><![CDATA[]]></return_msg>\n" +
                "</xml>";
    }

    String success() {
        return "<xml>\n" +
                "  <return_code><![CDATA[SUCCESS]]></return_code>\n" +
                "  <return_msg><![CDATA[OK]]></return_msg>\n" +
                "</xml>";
    }

二、小程式調起支付程式碼

返回的引數為統一下單介面返回的

 wx.requestPayment(
            {
            'timeStamp': data.timeStamp,
            'nonceStr': data.nonceStr,
            'package': data.package,
            'signType': 'MD5',
            'paySign': data.sign,
            'success':function(res){
               console.log(res)
            },
            'fail':function(res){
              console.log(res)
             
            }
          })