微信支付（公众号支付APIJS、app支付）服务端统一下单接口java版

一、微信公众号支付APIJS：

要完整的实现微信支付功能，需要前后端一起实现，还需要微信商户平台的配置。这里只是涉及服务端的代码。

jar包：pom.xml

<!-- ↓↓↓↓↓↓↓↓ 支付相关 ↓↓↓↓↓↓↓↓ -->
        <!-- http -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.2</version>
        </dependency>
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.1</version>
        </dependency>
        <!-- xml处理 -->
        <dependency>
            <groupId>org.jdom</groupId>
            <artifactId>jdom</artifactId>
            <version>1.1.3</version>
        </dependency>
        <!-- fast-json包-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.1.39</version>
        </dependency>
        <!-- ↑↑↑↑↑↑↑↑ 支付相关 ↑↑↑↑↑↑↑↑ -->

目录结构：

MD5Util.java

package webapp.payutil;

import java.security.MessageDigest;

public class MD5Util {
    private static String byteArrayToHexString(byte b[]) {
        StringBuilder resultSb = new StringBuilder();
        for (byte aB : b) resultSb.append(byteToHexString(aB));
        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    public static String MD5Encode(String origin, String charsetname) {
        String resultString = null;
        try {
            resultString = origin;
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname))
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes()));
            else
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes(charsetname)));
        } catch (Exception ignored) {
        }
        return resultString;
    }

    private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };
}

PayCommonUtil.java

package webapp.payutil;

import org.apache.http.Consts;
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.ssl.SSLContexts;
import org.apache.http.util.EntityUtils;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;

import javax.net.ssl.SSLContext;
import javax.servlet.http.HttpServletRequest;
import java.io.*;
import java.math.BigDecimal;
import java.net.ConnectException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.security.KeyStore;
import java.util.*;

public class PayCommonUtil {
    //微信参数配置
    public static String API_KEY = "kshdf554sdf4s5f2sf121sdfsd1f5sdf";
    public static String APPID = "wxd5609f7b5b4dd051";
    public static String MCH_ID = "1230989902";

    /**
     * 微信公众号支付
     * @param trade_no      订单号
     * @param totalAmount   支付金额
     * @param description   文字内容说明
     * @param attach        自定义参数 length=127
     * @param openId        微信公众号openId
     * @param wxnotify      回调地址
     * @param request       -
     * @return              -
     */
    public static SortedMap<String, Object> WxPublicPay(String trade_no, BigDecimal totalAmount, String description, String attach, String openId, String wxnotify, HttpServletRequest request) {
        Map<String, String> map = weixinPrePay(trade_no,totalAmount,description,attach,openId,wxnotify,request);
        SortedMap<String, Object> finalpackage = new TreeMap<>();
        finalpackage.put("appId", PayCommonUtil.APPID);
        finalpackage.put("timeStamp", System.currentTimeMillis() / 1000);
        finalpackage.put("nonceStr", getRandomString(32));
        finalpackage.put("package", "prepay_id=" + map.get("prepay_id"));
        finalpackage.put("signType", "MD5");
        String sign = PayCommonUtil.createSign(finalpackage);
        finalpackage.put("paySign", sign);
        return finalpackage;
    }

    /**
     *                      -
     * @param trade_no      订单号
     * @param totalAmount   支付金额
     * @param description   文字内容说明
     * @param attach        自定义参数 length=127
     * @param openid        微信公众号openId
     * @param wxnotify      回调地址
     * @param request       -
     * @return              -
     */
    private static Map<String, String> weixinPrePay(String trade_no, BigDecimal totalAmount, String description, String attach, String openid, String wxnotify, HttpServletRequest request) {
        SortedMap<String, Object> parameterMap = new TreeMap<>();
        parameterMap.put("appid", PayCommonUtil.APPID);
        parameterMap.put("mch_id", PayCommonUtil.MCH_ID);
        parameterMap.put("nonce_str", getRandomString(32));
        parameterMap.put("body", description);
        parameterMap.put("attach", attach);
        parameterMap.put("out_trade_no", trade_no);
        parameterMap.put("fee_type", "CNY");
        BigDecimal total = totalAmount.multiply(new BigDecimal(100));
        java.text.DecimalFormat df = new java.text.DecimalFormat("0");
        parameterMap.put("total_fee", df.format(total));
        parameterMap.put("spbill_create_ip", request.getRemoteAddr());
        parameterMap.put("notify_url", wxnotify);
        parameterMap.put("trade_type", "JSAPI");
        //trade_type为JSAPI是 openid为必填项
        parameterMap.put("openid", openid);
        String sign = PayCommonUtil.createSign(parameterMap);
        parameterMap.put("sign", sign);
        String requestXML = PayCommonUtil.getRequestXml(parameterMap);
        String result = PayCommonUtil.httpsRequest("https://api.mch.weixin.qq.com/pay/unifiedorder", "POST", requestXML);
        System.out.println(result);
        Map<String, String> map = null;
        try {
            map = PayCommonUtil.doXMLParse(result);
        } catch (JDOMException | IOException e) {
            e.printStackTrace();
        }
        return map;
    }

    //随机字符串生成
    private static String getRandomString(int length) { //length表示生成字符串的长度
        String base = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        Random random = new Random();
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < length; i++) {
            int number = random.nextInt(base.length());
            sb.append(base.charAt(number));
        }
        return sb.toString();
    }

    //请求xml组装
    private static String getRequestXml(SortedMap<String, Object> parameters){
        StringBuilder sb = new StringBuilder();
        sb.append("<xml>");
        Set es = parameters.entrySet();
        for (Object e : es) {
            Map.Entry entry = (Map.Entry) e;
            String key = (String) entry.getKey();
            String value = (String) entry.getValue();
            if ("attach".equalsIgnoreCase(key) || "body".equalsIgnoreCase(key) || "sign".equalsIgnoreCase(key)) {
                sb.append("<").append(key).append(">").append("<![CDATA[").append(value).append("]]></").append(key).append(">");
            } else {
                sb.append("<").append(key).append(">").append(value).append("</").append(key).append(">");
            }
        }
        sb.append("</xml>");
        return sb.toString();
    }

    //生成签名
    private static String createSign(SortedMap<String, Object> parameters){
        StringBuilder sb = new StringBuilder();
        Set es = parameters.entrySet();
        for (Object e : es) {
            Map.Entry entry = (Map.Entry) e;
            String k = (String) entry.getKey();
            Object v = entry.getValue();
            if (null != v && !"".equals(v)
                    && !"sign".equals(k) && !"key".equals(k)) {
                sb.append(k).append("=").append(v).append("&");
            }
        }
        sb.append("key=").append(API_KEY);
        System.out.println(sb.toString());
        return MD5Util.MD5Encode(sb.toString(), "UTF-8").toUpperCase();
    }

    /**
     * 验证回调签名
     * @param map
     * @return
     */
    public static boolean isTenpaySign(Map<String, String> map) {
        String charset = "utf-8";
        String signFromAPIResponse = map.get("sign");
        if (signFromAPIResponse == null || signFromAPIResponse.equals("")) {
            System.out.println("API返回的数据签名数据不存在，有可能被第三方篡改!!!");
            return false;
        }
        System.out.println("服务器回包里面的签名是:" + signFromAPIResponse);
        //过滤空 设置 TreeMap
        SortedMap<String,String> packageParams = new TreeMap<>();
        for (String parameter : map.keySet()) {
            String parameterValue = map.get(parameter);
            String v = "";
            if (null != parameterValue) {
                v = parameterValue.trim();
            }
            packageParams.put(parameter, v);
        }
        StringBuilder sb = new StringBuilder();
        Set es = packageParams.entrySet();
        for (Object e : es) {
            Map.Entry entry = (Map.Entry) e;
            String k = (String) entry.getKey();
            String v = (String) entry.getValue();
            if (!"sign".equals(k) && null != v && !"".equals(v)) {
                sb.append(k).append("=").append(v).append("&");
            }
        }
        sb.append("key=").append(API_KEY);
        //将API返回的数据根据用签名算法进行计算新的签名，用来跟API返回的签名进行比较
        //算出签名
        String tobesign = sb.toString();
        String resultSign = MD5Util.MD5Encode(tobesign, "utf-8").toUpperCase();
        String tenpaySign = packageParams.get("sign").toUpperCase();
        return tenpaySign.equals(resultSign);
    }

    //请求方法
    private static String httpsRequest(String requestUrl, String requestMethod, String outputStr) {
        try {
            URL url = new URL(requestUrl);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();

            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setUseCaches(false);
            // 设置请求方式（GET/POST）
            conn.setRequestMethod(requestMethod);
            conn.setRequestProperty("content-type", "application/x-www-form-urlencoded");
            // 当outputStr不为null时向输出流写数据
            if (null != outputStr) {
                OutputStream outputStream = conn.getOutputStream();
                // 注意编码格式
                outputStream.write(outputStr.getBytes("UTF-8"));
                outputStream.close();
            }
            // 从输入流读取返回内容
            InputStream inputStream = conn.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String str = null;
            StringBuilder buffer = new StringBuilder();
            while ((str = bufferedReader.readLine()) != null) {
                buffer.append(str);
            }
            // 释放资源
            bufferedReader.close();
            inputStreamReader.close();
            inputStream.close();
            conn.disconnect();
            return buffer.toString();
        } catch (ConnectException ce) {
            System.out.println("连接超时：{}"+ ce);
        } catch (Exception e) {
            System.out.println("https请求异常：{}"+ e);
        }
        return null;
    }

    //退款的请求方法
    public static String httpsRequest2(String requestUrl, String requestMethod, String outputStr) throws Exception {
        KeyStore keyStore  = KeyStore.getInstance("PKCS12");
        StringBuilder res = new StringBuilder("");
        try (FileInputStream instream = new FileInputStream(new File("/home/apiclient_cert.p12"))) {
            keyStore.load(instream, "".toCharArray());
        }

        // Trust own CA and all self-signed certs
        SSLContext sslcontext = SSLContexts.custom()
                .loadKeyMaterial(keyStore, "1313329201".toCharArray())
                .build();
        // Allow TLSv1 protocol only
        SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
                sslcontext,
                new String[] { "TLSv1" },
                null,
                SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);
        try (CloseableHttpClient httpclient = HttpClients.custom()
                .setSSLSocketFactory(sslsf)
                .build()) {
            HttpPost httpost = new HttpPost("https://api.mch.weixin.qq.com/secapi/pay/refund");
            httpost.addHeader("Connection", "keep-alive");
            httpost.addHeader("Accept", "*/*");
            httpost.addHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
            httpost.addHeader("Host", "api.mch.weixin.qq.com");
            httpost.addHeader("X-Requested-With", "XMLHttpRequest");
            httpost.addHeader("Cache-Control", "max-age=0");
            httpost.addHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0) ");
            StringEntity entity2 = new StringEntity(outputStr, Consts.UTF_8);
            httpost.setEntity(entity2);
            System.out.println("executing request" + httpost.getRequestLine());
            try (CloseableHttpResponse response = httpclient.execute(httpost)) {
                HttpEntity entity = response.getEntity();
                System.out.println("----------------------------------------");
                System.out.println(response.getStatusLine());
                if (entity != null) {
                    System.out.println("Response content length: " + entity.getContentLength());
                    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(entity.getContent()));
                    String text = "";
                    res.append(text);
                    while ((text = bufferedReader.readLine()) != null) {
                        res.append(text);
                        System.out.println(text);
                    }
                }
                EntityUtils.consume(entity);
            }
        }
        return  res.toString();

    }

    //xml解析
    public static Map doXMLParse(String strxml) throws JDOMException, 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 = builder.build(in);
        Element root = doc.getRootElement();
        List list = root.getChildren();
        for (Object aList : list) {
            Element e = (Element) aList;
            String k = e.getName();
            String v = "";
            List children = e.getChildren();
            if (children.isEmpty()) {
                v = e.getTextNormalize();
            } else {
                v = getChildrenText(children);
            }
            m.put(k, v);
        }
        //关闭流
        in.close();
        return m;
    }

    private static String getChildrenText(List children) {
        StringBuilder sb = new StringBuilder();
        if(!children.isEmpty()) {
            for (Object aChildren : children) {
                Element e = (Element) aChildren;
                String name = e.getName();
                String value = e.getTextNormalize();
                List list = e.getChildren();
                sb.append("<").append(name).append(">");
                if (!list.isEmpty()) {
                    sb.append(getChildrenText(list));
                }
                sb.append(value);
                sb.append("</").append(name).append(">");
            }
        }

        return sb.toString();
    }
}

WeiXinPayController.java

package webapp.controller;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import org.jdom.JDOMException;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import webapp.payutil.PayCommonUtil;

import javax.servlet.http.HttpServletRequest;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigDecimal;
import java.util.Map;
import java.util.SortedMap;
import java.util.UUID;

@Controller
@RequestMapping(value = "/api")
public class WeiXinPayController {
    private static String wxnotify = "/api/json/money/wxpay/succ";

    /**
     * @param totalAmount    支付金额
     * @param description    描述
     * @param openId         微信公众号openId   （可以前端传code,然后后台再通过微信对应接口换取openId）
     * @param request -
     * @return -
     */
    @RequestMapping(value = "/weixin/weixinPay/{totalAmount}/{description}/{openId}",
            method = RequestMethod.GET,
            produces = MediaType.APPLICATION_JSON_VALUE)
    @ResponseBody
    public SortedMap<String, Object> ToPay(@PathVariable BigDecimal totalAmount, @PathVariable String description, @PathVariable String openId, HttpServletRequest request) {
        String sym = request.getRequestURL().toString().split("/api/")[0];
        // 订单号
        String tradeNo = UUID.randomUUID().toString().replaceAll("-", "").toLowerCase().substring(0,32);
        // 回调地址
        String notifyUrl = sym + wxnotify;
        // 自定义参数
        Long userId = 100L; //对应用户id自己修改
        JSONObject jsAtt = new JSONObject();
        jsAtt.put("uid", userId);
        String attach = jsAtt.toJSONString();
        // 返回预支付参数
        return PayCommonUtil.WxPublicPay(tradeNo, totalAmount, description, attach, openId, notifyUrl, request);
    }

    /**
     * 支付回调地址
     * @param request
     * @return
     * @throws IOException
     */
    @RequestMapping(value = "/json/money/wxpay/succ",
            produces = MediaType.APPLICATION_JSON_VALUE)
    public String wxpaySucc(HttpServletRequest request) throws IOException {
        System.out.println("微信支付回调");
        InputStream inStream = request.getInputStream();
        ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = inStream.read(buffer)) != -1) {
            outSteam.write(buffer, 0, len);
        }
        String resultxml = new String(outSteam.toByteArray(), "utf-8");
        Map<String, String> params = null;
        try {
            params = PayCommonUtil.doXMLParse(resultxml);
        } catch (JDOMException e) {
            e.printStackTrace();
        }
        outSteam.close();
        inStream.close();
        if (!PayCommonUtil.isTenpaySign(params)) {
            // 支付失败
            return "fail";
        } else {
            System.out.println("===============付款成功==============");
            // ------------------------------
            // 处理业务开始
            // ------------------------------
            // 此处处理订单状态，结合自己的订单数据完成订单状态的更新
            // ------------------------------

            String total_fee = params.get("total_fee");
            double v = Double.valueOf(total_fee) / 100;
            // 取出用户id
            String attach = params.get("attach");
            JSONObject jsonObject = JSON.parseObject(attach);
            Long userId = Long.parseLong(jsonObject.get("uid").toString());

            //更新
            //updateUserPay(userId, String.valueOf(v));

            // 处理业务完毕
            // ------------------------------
            return "success";
        }
    }

}