描述

微信支付可分為V2版本與V3版本，項(xiàng)目需要使用V3版本微信支付，簡述java如何實(shí)現(xiàn)微信支付V3版本

支付流程

概要流程：

1、小程序，傳遞微信支付需要參數(shù)，如商品價(jià)格等，調(diào)用后端的支付訂單接口
2、后端調(diào)用微信支付系統(tǒng)后生成6個(gè)必要參數(shù)返回給前端。
后臺(tái)調(diào)用微信支付系統(tǒng)需要組裝必要的參數(shù)：
{
	"amount": {
		"total": 100 //支付金額 這個(gè)是分單位 100分=1元
	},
	"mchid": "1621239178", //商戶號(hào)
	"description": "充值支付",//支付描述
	"notify_url": "http://127.0.0.1/pay/payNotify",//支付后回調(diào)接收地址
	"payer": {
		"openid": "o4GgauInH_RCEdvrrNGrntXDuXXX" //當(dāng)前用戶的openID
	},
	"out_trade_no": "3_6318816544250929333",//支付的訂單號(hào)，支付后回調(diào)信息會(huì)將這個(gè)訂單號(hào)帶回來
	"appid": "wx1d0b55c33e1e0e333" //小程序的APPID
}
6個(gè)必要參數(shù)用于小程序能否成功喚起微信支付
如下：
訂單號(hào)、金額、openid等去請(qǐng)求微信下單接口，微信返回預(yù)支付交易會(huì)話標(biāo)識(shí)prepay_id
后端給appid、timestamp、nonceStr、prepayId簽名，并將簽名、timestamp、nonceStr、prepay_id返回給小程序
{
	"appId": "wx1d0b55c33e1e0e333",//小程序的APPID
	"timeStamp": "16279901923",//時(shí)間戳
	"nonceStr": "asd1231asdas",//隨機(jī)串，保證唯一
	"package": "sdgscvb",
	"signType": "RSA",//簽名類型
	"paySign": "zzzghhxcvsdfs2q3412sdfsdf" //簽名信息
}
3、小程序調(diào)用wx.requestPayment拉起微信支付
4、用戶支付后，微信支付系統(tǒng)會(huì)回調(diào)信息，后端接收，做對(duì)應(yīng)的業(yè)務(wù)邏輯處理

微信支付前必要準(zhǔn)備

1、微信官方文檔–小程序支付接口文檔描述（最終是組成概要流程中的參數(shù)形式）：
https://pay.weixin.qq.com/wiki/doc/apiv3/apis/chapter3_5_1.shtml
2、微信官方文檔–商戶號(hào)及微信V3證書下載
https://pay.weixin.qq.com/wiki/doc/apiv3/open/pay/chapter2_8_1.shtml
V3證書下載成功后文件（共3個(gè)）如下圖：
apiclient_key.pem，apiclient_cert.pem，apiclient_cert.p12

maven導(dǎo)包

<dependency>
    <groupId>com.github.javen205</groupId>
    <artifactId>IJPay-WxPay</artifactId>
</dependency>

文件配置

wxpay_v3.properties（微信支付配置，有appId，商戶id，API密鑰，證書地址，回調(diào)地址，
該文件在resource根目錄）
文件地址等信息根據(jù)自己項(xiàng)目情況自行配置

文章來源地址http://www.zghlxwxcb.cn/news/detail-656971.html

java代碼

微信V3證書支付需要根據(jù)下載的3個(gè)證書文件（微信支付前必要準(zhǔn)備第2點(diǎn)的）生成第四個(gè)證書文件（重要、重要、重要），
微信支付前，必須先生成這個(gè)文件，不然V3版本的支付無法喚醒，
調(diào)用這個(gè)接口生成即可：http://127.0.0.1:8080/項(xiàng)目名稱/v1/wx/pay/createPlatformCert
后續(xù)會(huì)說明如何生成
廢話不多說，直接上代碼

Controller

import com.core.def.vo.renew.IWxPayParamVO;
import com.wechat.service.WXPayNewService;
import lombok.RequiredArgsConstructor;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;
import java.util.Map;

/**
 * 微信支付
 * @author 夕四
 **/
@RequiredArgsConstructor
@RestController
@RequestMapping(value = "/v1/wx/pay")
public class WXPayController {
    private final WXPayNewService wxPayNewService;

    /**
     * 微信統(tǒng)一下單接口
     * @param iWxPayParamVO 業(yè)務(wù)需要的參數(shù)
     * @return
     */
    @PostMapping("/doUnifiedOrder")
    public Map doUnifiedOrder(@RequestBody IWxPayParamVO iWxPayParamVO) throws Exception {
        return wxPayNewService.doUnifiedOrder(iWxPayParamVO);
    }

    /**
     * 微信支付的回調(diào)接收接口
     * @param request
     * @param response
     */
    @RequestMapping(value = "/payNotify", method = {org.springframework.web.bind.annotation.RequestMethod.POST, org.springframework.web.bind.annotation.RequestMethod.GET})
    public void callBack(HttpServletRequest request, HttpServletResponse response) {
        wxPayNewService.callBack(request, response);
    }

    /**
     * 生成v3證書
     *
     */
    @RequestMapping("/createPlatformCert")
    @ResponseBody
    public String createPlatformCert() throws IOException {
        return wxPayNewService.createPlatformCert();
    }
}

Service

import com.core.def.vo.renew.IWxPayParamVO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;
import java.util.Map;

/**
 * 小程序微信支付
 *
 * @author 夕四
 **/
public interface WXPayNewService {
    /**
     * 微信統(tǒng)一下單接口
     *
     * @param iWxPayParamVO
     * @return
     * @throws Exception
     */
    Map doUnifiedOrder(IWxPayParamVO iWxPayParamVO) throws Exception;

    /**
     * 獲取v3的證書
     *
     * @return
     * @throws IOException
     */
    String createPlatformCert() throws IOException;

    /**
     * 微信支付回調(diào)接口
     *
     * @param request
     * @param response
     */
    void callBack(HttpServletRequest request, HttpServletResponse response);
}

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.date.DateUnit;
import cn.hutool.core.date.DateUtil;
import cn.hutool.core.io.FileUtil;
import cn.hutool.core.util.RandomUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.http.ContentType;
import cn.hutool.json.JSONArray;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.vo.renew.IWxPayParamVO;
import com.config.WxPayParameterConfig;
import com.wechat.service.WXPayNewService;
import com.ijpay.core.IJPayHttpResponse;
import com.ijpay.core.enums.RequestMethod;
import com.ijpay.core.kit.AesUtil;
import com.ijpay.core.kit.HttpKit;
import com.ijpay.core.kit.PayKit;
import com.ijpay.core.kit.WxPayKit;
import com.ijpay.core.utils.DateTimeZoneUtil;
import com.ijpay.wxpay.WxPayApi;
import com.ijpay.wxpay.enums.WxApiType;
import com.ijpay.wxpay.enums.WxDomain;
import lombok.RequiredArgsConstructor;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigDecimal;
import java.nio.charset.StandardCharsets;
import java.security.cert.X509Certificate;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.*;

/**
 * @author 夕四
 **/
@RequiredArgsConstructor
@Slf4j
@Service
public class WXPayNewServiceImpl implements WXPayNewService {

	@Override
    public Map doUnifiedOrder(IWxPayParamVO iWxPayParamVO) throws Exception {
        //先寫死1， 1就是1分錢，100=1元
        Integer price = 1;
        //商戶訂單號(hào)(隨機(jī)字符串),這個(gè)回調(diào)的時(shí)候會(huì)給回
        String orderSn = generateNonceStr();
        //微信用戶openId
        String openid = iWxPayParamVO.getOpenId();
        //這個(gè)是微信小程序的appid
        String appid = iWxPayParamVO.getAppId();
        //商戶號(hào)ID
        String mchId = iWxPayParamVO.getMchId();
        //設(shè)置下支付的超時(shí)時(shí)間
        String timeExpire = DateTimeZoneUtil.dateToTimeZone(System.currentTimeMillis() + 1000 * 60 * 3);
        Map<String, Object> data = requestWxPayParam(mchId,orderSn, openid, price, appid, timeExpire);
        log.info("統(tǒng)一下單參數(shù) {}", JSONUtil.toJsonStr(data));
        //這個(gè)是證書文件，先寫死，后續(xù)調(diào)整成讀取證書文件的服務(wù)器存放地址
        String privateKeyPath = "D:\\MyTools\\WXWork\\WxPayFile\\apiclient_key.pem";
        //請(qǐng)求下單
        IJPayHttpResponse response = WxPayApi.v3(
                RequestMethod.POST,
                WxDomain.CHINA.toString(),
                WxApiType.JS_API_PAY.toString(),
                // 商戶號(hào)
                mchId,
                // 獲取證書序列號(hào)
                getSerialNumber(),
                null,
                // 私鑰
                privateKeyPath,
                // 請(qǐng)求參數(shù)
                JSONUtil.toJsonStr(data)
        );
        log.info("統(tǒng)一下單響應(yīng) {}", response);
        //這個(gè)就是小程序喚醒微信支付必要的那6個(gè)參數(shù)了
        Map<String, String> map =new HashMap<>();
        if (response.getStatus() == 200) {
            //這個(gè)是證書文件，先寫死，后續(xù)調(diào)整成讀取證書文件的服務(wù)器存放地址
            // 根據(jù)證書序列號(hào)查詢對(duì)應(yīng)的證書來驗(yàn)證簽名結(jié)果
            String platformCertPath = "D:\\MyTools\\WXWork\\WxPayFile\\cert.pem";
            //平臺(tái)證書
            boolean verifySignature = WxPayKit.verifySignature(response, platformCertPath);
            log.info("verifySignature: {}", verifySignature);
            if (verifySignature) {
                String body = response.getBody();
                JSONObject jsonObject = JSONUtil.parseObj(body);
                String prepayId = jsonObject.getStr("prepay_id");
                // 私鑰
                map = WxPayKit.jsApiCreateSign(appid, prepayId,privateKeyPath);
                log.info("喚起支付參數(shù):{}", map);
            }
        }
        //todo 微信預(yù)支付的訂單新入庫，為了業(yè)務(wù)查詢記錄

        return map;
    }

    @Override
    public void callBack(HttpServletRequest request, HttpServletResponse response) {
        log.info("收到微信支付回調(diào)");
        Map<String, String> map = new HashMap<>(12);
        try {
            String timestamp = request.getHeader("Wechatpay-Timestamp");
            String nonce = request.getHeader("Wechatpay-Nonce");
            String serialNo = request.getHeader("Wechatpay-Serial");
            String signature = request.getHeader("Wechatpay-Signature");

            log.info("timestamp:{} nonce:{} serialNo:{} signature:{}", timestamp, nonce, serialNo, signature);
            String result = HttpKit.readData(request);
            log.info("支付通知密文 {}", result);
            // 根據(jù)證書序列號(hào)查詢對(duì)應(yīng)的證書來驗(yàn)證簽名結(jié)果
            String platformCertPath = "D:\\MyTools\\WXWork\\WxPayFile\\cert.pem";
            //這個(gè)商戶號(hào)對(duì)應(yīng)的那個(gè)V3秘鑰
            String mckKey="cjajsrtasdqw21523asdf1";
            //需要通過證書序列號(hào)查找對(duì)應(yīng)的證書，verifyNotify 中有驗(yàn)證證書的序列號(hào)
            String plainText = WxPayKit.verifyNotify(serialNo, result, signature, nonce, timestamp,mckKey, platformCertPath);
            log.info("支付通知明文 {}", plainText);
            //這個(gè)就是具體的業(yè)務(wù)情況
            savePayPlainText(plainText);
            //回復(fù)微信
            if (StrUtil.isNotEmpty(plainText)) {
                response.setStatus(200);
                map.put("code", "SUCCESS");
                map.put("message", "SUCCESS");
            } else {
                response.setStatus(500);
                map.put("code", "ERROR");
                map.put("message", "簽名錯(cuò)誤");
            }
            response.setHeader("Content-type", ContentType.JSON.toString());
            response.getOutputStream().write(JSONUtil.toJsonStr(map).getBytes(StandardCharsets.UTF_8));
            response.flushBuffer();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public String createPlatformCert() {
        //商戶號(hào)ID
        String mchId = "6382395623";
        //這個(gè)商戶號(hào)對(duì)應(yīng)的那個(gè)V3秘鑰
        String mckKey="cjajsrtasdqw21523asdf1";
        // 獲取平臺(tái)證書列表
        try {
            //這個(gè)是證書文件，先寫死，后續(xù)調(diào)整成讀取證書文件的服務(wù)器存放地址
            String privateKeyPath = "D:\\MyTools\\WXWork\\WxPayFile\\apiclient_key.pem";
            IJPayHttpResponse response = WxPayApi.v3(
                    RequestMethod.GET,
                    WxDomain.CHINA.toString(),
                    WxApiType.GET_CERTIFICATES.toString(),
                    mchId,
                    getSerialNumber(),
                    null,
                    privateKeyPath,
                    ""
            );

            String timestamp = response.getHeader("Wechatpay-Timestamp");
            String nonceStr = response.getHeader("Wechatpay-Nonce");
            String serialNumber = response.getHeader("Wechatpay-Serial");
            String signature = response.getHeader("Wechatpay-Signature");

            String body = response.getBody();
            int status = response.getStatus();

            log.info("serialNumber: {}", serialNumber);
            log.info("status: {}", status);
            log.info("body: {}", body);
            int isOk = 200;
            // 根據(jù)證書序列號(hào)查詢對(duì)應(yīng)的證書來驗(yàn)證簽名結(jié)果
            String platformCertPath = "D:\\MyTools\\WXWork\\WxPayFile\\cert.pem";
            if (status == isOk) {
                JSONObject jsonObject = JSONUtil.parseObj(body);
                JSONArray dataArray = jsonObject.getJSONArray("data");
                // 默認(rèn)認(rèn)為只有一個(gè)平臺(tái)證書
                JSONObject encryptObject = dataArray.getJSONObject(0);
                JSONObject encryptCertificate = encryptObject.getJSONObject("encrypt_certificate");
                String associatedData = encryptCertificate.getStr("associated_data");
                String cipherText = encryptCertificate.getStr("ciphertext");
                String nonce = encryptCertificate.getStr("nonce");
                String serialNo = encryptObject.getStr("serial_no");
                //生成第四個(gè)證書文件
                final String platSerialNo = savePlatformCert(associatedData,mckKey, nonce, cipherText, platformCertPath);
                log.info("平臺(tái)證書序列號(hào): {} serialNo: {}", platSerialNo, serialNo);
            }
            // 根據(jù)證書序列號(hào)查詢對(duì)應(yīng)的證書來驗(yàn)證簽名結(jié)果
            boolean verifySignature = WxPayKit.verifySignature(response, platformCertPath);
            log.info("verifySignature:{}" + verifySignature);
            return body;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
    
    private String savePlatformCert(String associatedData, String apiKey3, String nonce, String cipherText, String certPath) {
        try {
            AesUtil aesUtil = new AesUtil(apiKey3.getBytes(StandardCharsets.UTF_8));
            // 平臺(tái)證書密文解密
            // encrypt_certificate 中的  associated_data nonce  ciphertext
            String publicKey = aesUtil.decryptToString(
                    associatedData.getBytes(StandardCharsets.UTF_8),
                    nonce.getBytes(StandardCharsets.UTF_8),
                    cipherText
            );
            log.info("獲取證書key：{},保存路徑platformCert:{}", publicKey, certPath);
            //將生成的證書寫入指定路徑，文件名為：cert.pem
            FileOutputStream fos = new FileOutputStream(certPath);
            fos.write(publicKey.getBytes());
            fos.close();

            // 獲取平臺(tái)證書序列號(hào)
            X509Certificate certificate = PayKit.getCertificate(new ByteArrayInputStream(publicKey.getBytes()));
            return certificate.getSerialNumber().toString(16).toUpperCase();
        } catch (Exception e) {
            log.error("寫入證書錯(cuò)誤:{}", e);
            return e.getMessage();
        }
    }

    /**
     * 保存訂單的支付通知明文
     *
     * @param plainText
     */
    private void savePayPlainText(String plainText) {
        JSONObject jsonObject = JSONUtil.parseObj(plainText);
        //這個(gè)就是發(fā)起訂單時(shí)的那個(gè)訂單號(hào)
        String outTradeNo = jsonObject.getStr("out_trade_no");
        //todo 把微信支付回調(diào)的明文消息存進(jìn)數(shù)據(jù)庫，方便后續(xù)校驗(yàn)查看

        //todo 把微信支付后需要處理的具體業(yè)務(wù)處理了
    }

    /**
     * 直連支付組裝參數(shù)
     *
     * @return
     */
    private Map<String, Object> requestWxPayParam(String mchId,String orderSn, String openid, Integer price,String appid, String timeExpire) {
        Map<String, Object> data = new HashMap<String, Object>();
        Map<String, String> user = new HashMap<>();
        user.put("openid", openid);
        Map<String, Object> fee = new HashMap<>();
        fee.put("total", price);
        //APPID
        data.put("appid", appid);
        //商戶ID
        data.put("mchid", mchId);
        //生成的隨機(jī)字符串
        data.put("description", "*****支付");
        data.put("out_trade_no", orderSn);
        //支付金額，單位分,1是1分錢
        data.put("amount", fee);
        data.put("time_expire", timeExpire);
        //通知地址，用戶支付成功之后，微信訪問的接口
        data.put("notify_url", "填上你自己的微信回調(diào)接收地址");
        data.put("payer", user);
        return data;
    }

    /**
     * 獲取證書序列號(hào)
     *
     * @return
     */
    private String getSerialNumber() throws IOException {
        //這個(gè)是證書文件，先寫死，后續(xù)調(diào)整成讀取證書文件的服務(wù)器存放地址
        String certPath = "D:\\MyTools\\WXWork\\WxPayFile\\apiclient_cert.pem";
        log.info("path:{}", certPath);
        // 獲取證書序列號(hào)
        X509Certificate certificate = PayKit.getCertificate(FileUtil.getInputStream(certPath));
        String serialNo = certificate.getSerialNumber().toString(16).toUpperCase();
        log.info("獲取證書序列號(hào)：{},", serialNo);
        return serialNo;
    }

    /**
     * 獲取隨機(jī)字符串 Nonce Str
     *
     * @return String 隨機(jī)字符串
     */
    public String generateNonceStr() {
        StringBuffer stringBuffer = new StringBuffer();
        int prefix = RandomUtil.randomInt(10000, 99999);
        int suffix = RandomUtil.randomInt(10000, 99999);
        Long time = System.currentTimeMillis();
        return stringBuffer.append(prefix).append(time).append(suffix).toString();
    }
}

到此，微信支付對(duì)接業(yè)務(wù)邏輯處理完成

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