微信直连商户V3支付（可直接使用）

朴灿烈づ我的快乐病毒、 2023-10-13 15:19 2阅读 0赞

# 直连商户模式和服务商模式区别： #

> 直连商户：例如张三开了一个小程序，然后别人在这个小程序买东西，结账的时候，钱是直接打到张三的账号上的。
> 
> 服务商模式：例如张三开了一个小程序，然后这个小程序中有一个开分店的功能，然后别人在分店购买东西，在结账的时候，钱是直接打到分店的负责人的账号上的  
> **本文章说的是直连商户模式（服务商模式请看：**[https://blog.csdn.net/qq\_26112725/article/details/131684591][https_blog.csdn.net_qq_26112725_article_details_131684591]**）**

# 微信支付逻辑（重点）： #

> ![44ce6b79061943038deae8091cf7e087.png][]
> 
>   
> 前端点击支付按钮，在调起微信自带支付页面之前，要往后端发一个请求，后端先是负责调用微信的 "统一下单" 接口，在调用这个接口的时候，会把本地订单号也一起发过去，然后会得到一个 prepay\_id ，然后再针对 prepay\_id 和一些参数做一个算法，得到相对应的签名值，然后返回给前端，然后前端就可以根据这些返回值调用支付，就可以支付了
> 
> 如果支付成功，那就ok了，因为有把本地的订单号一起传过去给微信那边，所以就相当于这个本地的订单号跟微信那边的订单绑定了，所以只要支付了腾讯那边的订单，那就相当于完成了本地订单。

--------------------

# 1.申请证书，设置V3秘钥 #

![e215ad3e485c41948516b21db0454dbf.png][]

# 2.设置APPid账号管理 #

![353dccc71a18461ea59ff890ff081d4b.png][]

# 3.maven地址 #

>     <dependency>
>                 <groupId>com.github.wechatpay-apiv3</groupId>
>                 <artifactId>wechatpay-apache-httpclient</artifactId>
>                 <version>0.4.7</version>
>             </dependency>

# 4.公共参数接口 #

>     /**
>      * 直连商户
>      */
>     public interface DirectConnection {
>     
>         String NOTIFY_URL = ""; //支付成功后的回调地址
>         String MCH_ID = ""; //商户号
>         String MCH_SERIAL_NO = ""; //商户证书序列号
>         String API_3KEY = "";   //V3密钥
>         String APP_ID = "";     //小程序或者公众号的ApId
>         String privateKey = "MIIEvAIBADANBgkqhkiG9w0BAQEFAASCBKYwggSiAgEAAoIBAQDOsZnx5Nh4qK7O" +
>                 "vzbDOQu5UMtSdoZWyqOC+gFNVAB7aPAzQwgN7OAUt7G8synPRdovQ/l116dZ0ZiX"+
>                 "XQX3Le8/o5szRH6LxpqcpFMaZg2N/HOydyTMaHI0wnZIc9BXR8aaXl7uVQnydF40"+
>                 "FoWicge6vTCXOyjirTpS2PGKy9+hu0vx7GbX1NUDl2hNXkH54pdWn5eof1fnbh/V"+
>                 "45q/OS7d9qnpYfs1ff+0nA=="; // 商户证书序列号对应的证书秘钥
>     
>     }
> 
> 其中的 **商户证书序列号对应的证书秘钥** 在下载好的证书的这个地方：
> 
>   
> ![bb485ad4bd2e4018a7e4eab0dddb767e.png][]
> 
> **其中红色框起来的就是商户证书序列号对应的证书秘钥：**
> 
>   
> ![28fc165bfdcb4540895fa84db76897d2.png][]

# 5.下单工具类 #

>     package com.example.demo.zhifu;
>     
>     import cn.hutool.core.util.RandomUtil;
>     import com.alibaba.fastjson2.JSONObject;
>     import com.fasterxml.jackson.databind.JsonNode;
>     import com.fasterxml.jackson.databind.ObjectMapper;
>     import com.fasterxml.jackson.databind.node.ObjectNode;
>     import com.wechat.pay.contrib.apache.httpclient.WechatPayHttpClientBuilder;
>     import com.wechat.pay.contrib.apache.httpclient.auth.PrivateKeySigner;
>     import com.wechat.pay.contrib.apache.httpclient.auth.Verifier;
>     import com.wechat.pay.contrib.apache.httpclient.auth.WechatPay2Credentials;
>     import com.wechat.pay.contrib.apache.httpclient.auth.WechatPay2Validator;
>     import com.wechat.pay.contrib.apache.httpclient.cert.CertificatesManager;
>     import com.wechat.pay.contrib.apache.httpclient.exception.HttpCodeException;
>     import com.wechat.pay.contrib.apache.httpclient.exception.NotFoundException;
>     import com.wechat.pay.contrib.apache.httpclient.util.PemUtil;
>     import org.apache.http.client.methods.CloseableHttpResponse;
>     import org.apache.http.client.methods.HttpPost;
>     import org.apache.http.entity.StringEntity;
>     import org.apache.http.impl.client.CloseableHttpClient;
>     import org.apache.http.util.EntityUtils;
>     
>     import java.io.ByteArrayInputStream;
>     import java.io.ByteArrayOutputStream;
>     import java.io.IOException;
>     import java.nio.charset.StandardCharsets;
>     import java.security.*;
>     import java.util.Base64;
>     
>     /**
>      * 直连商户的下单工具类
>      * @author liaozan8888@163.com
>      */
>     
>     public class PayUtil {
>     
>         private CloseableHttpClient httpClient;
>         private CertificatesManager certificatesManager;
>         private Verifier verifier;
>         private PrivateKey merchantPrivateKey;
>     
>         {
>             try {
>                 merchantPrivateKey = PemUtil.loadPrivateKey(new ByteArrayInputStream(DirectConnection.privateKey.getBytes("utf-8")));
>                 // 获取证书管理器实例
>                 certificatesManager = CertificatesManager.getInstance();
>                 // 向证书管理器增加需要自动更新平台证书的商户信息
>                 certificatesManager.putMerchant(DirectConnection.MCH_ID, new WechatPay2Credentials(DirectConnection.MCH_ID,
>                                 new PrivateKeySigner(DirectConnection.MCH_SERIAL_NO, merchantPrivateKey)),
>                         DirectConnection.API_3KEY.getBytes(StandardCharsets.UTF_8));
>                 // 从证书管理器中获取verifier
>                 verifier = certificatesManager.getVerifier(DirectConnection.MCH_ID);
>                 httpClient = WechatPayHttpClientBuilder.create()
>                         .withMerchant(DirectConnection.MCH_ID, DirectConnection.MCH_SERIAL_NO, merchantPrivateKey)
>                         .withValidator(new WechatPay2Validator(certificatesManager.getVerifier(DirectConnection.MCH_ID)))
>                         .build();
>             } catch (IOException | GeneralSecurityException | HttpCodeException | NotFoundException e) {
>                 throw new RuntimeException(e);
>             }
>         }
>     
>     
>         /**
>          * 统一下单，获取到 prepay_id ，然后获取签名，调起
>          * @param total
>          * @param description
>          * @return
>          * @throws Exception
>          */
>         public String requestwxChatPay(String orderSn, int total, String description,String openid) throws Exception {
>     
>             HttpPost httpPost = new HttpPost("https://api.mch.weixin.qq.com/v3/pay/transactions/jsapi");
>             httpPost.addHeader("Accept", "application/json");
>             httpPost.addHeader("Content-type", "application/json; charset=utf-8");
>     
>             ByteArrayOutputStream bos = new ByteArrayOutputStream();
>             ObjectMapper objectMapper = new ObjectMapper();
>             //组合请求参数JSON格式
>             ObjectNode rootNode = objectMapper.createObjectNode();
>             rootNode.put("mchid", DirectConnection.MCH_ID)
>                     .put("appid", DirectConnection.APP_ID)
>                     .put("notify_url", DirectConnection.NOTIFY_URL + "returnNotify")
>                     .put("description", description)
>                     .put("out_trade_no", orderSn);
>             rootNode.putObject("amount")
>                     // total：金额，以分为单位，假如是10块钱，那就要写 1000
>                     .put("total", total)
>                     .put("currency", "CNY");
>             rootNode.putObject("payer")
>                     // openid：用户在该小程序或者公众号下的openid
>                     .put("openid", openid);
>             try {
>                 objectMapper.writeValue(bos, rootNode);
>                 httpPost.setEntity(new StringEntity(bos.toString("UTF-8"), "UTF-8"));
>                 //获取预支付ID
>                 CloseableHttpResponse response = httpClient.execute(httpPost);
>                 String bodyAsString = EntityUtils.toString(response.getEntity());
>                 //微信成功响应
>                 int statusCode = response.getStatusLine().getStatusCode();
>                 if (statusCode == 200) {
>                     //时间戳
>                     String timestamp = System.currentTimeMillis() / 1000 + "";
>                     //随机字符串
>                     String nonce = RandomUtil.randomString(32);
>                     StringBuilder builder = new StringBuilder();
>     
>                     // Appid
>                     builder.append(DirectConnection.APP_ID).append("\n");
>                     // 时间戳
>                     builder.append(timestamp).append("\n");
>                     // 随机字符串
>                     builder.append(nonce).append("\n");
>                     JsonNode jsonNode = objectMapper.readTree(bodyAsString);
>                     // 预支付会话ID
>                     builder.append("prepay_id=").append(jsonNode.get("prepay_id").textValue()).append("\n");
>                     //获取签名
>                     String sign = this.sign(builder.toString().getBytes("utf-8"), merchantPrivateKey);
>     
>                     JSONObject jsonMap = new JSONObject();
>                     jsonMap.put("noncestr", nonce);
>                     jsonMap.put("timestamp", timestamp);
>                     jsonMap.put("prepayid", jsonNode.get("prepay_id").textValue());
>                     jsonMap.put("sign", sign);
>                     jsonMap.put("appid", DirectConnection.APP_ID);
>                     jsonMap.put("partnerid", DirectConnection.MCH_ID);
>     
>                     return jsonMap.toJSONString();//响应签名数据，前端拿着响应数据调起微信SDK
>                 }
>             } catch (Exception e) {
>                 e.printStackTrace();
>             }
>             return null;
>         }
>     
>         /**
>     
>          /**
>          * 计算签名
>          *
>          * @param message
>          * @param yourPrivateKey
>          * @return
>          */
>         private String sign(byte[] message, PrivateKey yourPrivateKey) {
>             try {
>                 Signature sign = Signature.getInstance("SHA256withRSA");
>                 sign.initSign(yourPrivateKey);
>                 sign.update(message);
>                 return Base64.getEncoder().encodeToString(sign.sign());
>             } catch (NoSuchAlgorithmException | InvalidKeyException | SignatureException e) {
>                 e.printStackTrace();
>             }
>             return "";
>         }
>     
>     }

# 6.回调签名工具类 #

>     package com.example.demo.zhifu;
>     
>     /**
>      * @Description:
>      * @Author sk
>      * @Date: 2023/7/5 14:31
>      */
>     
>     import javax.crypto.Cipher;
>     import javax.crypto.NoSuchPaddingException;
>     import javax.crypto.spec.GCMParameterSpec;
>     import javax.crypto.spec.SecretKeySpec;
>     import java.io.IOException;
>     import java.security.GeneralSecurityException;
>     import java.security.InvalidAlgorithmParameterException;
>     import java.security.InvalidKeyException;
>     import java.security.NoSuchAlgorithmException;
>     import java.util.Base64;
>     
>     /**
>      * 回调签名配置
>      * @author liaozan8888@163.com
>      */
>     public class AesUtil {
>         static final int KEY_LENGTH_BYTE = 32;
>         static final int TAG_LENGTH_BIT = 128;
>         private final byte[] aesKey;
>     
>         public AesUtil(byte[] key) {
>             if (key.length != KEY_LENGTH_BYTE) {
>                 throw new IllegalArgumentException("无效的ApiV3Key，长度必须为32个字节");
>             }
>             this.aesKey = key;
>         }
>         public String decryptToString(byte[] associatedData, byte[] nonce, String ciphertext) throws GeneralSecurityException, IOException {
>             try {
>                 Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
>     
>                 SecretKeySpec key = new SecretKeySpec(aesKey, "AES");
>                 GCMParameterSpec spec = new GCMParameterSpec(TAG_LENGTH_BIT, nonce);
>     
>                 cipher.init(Cipher.DECRYPT_MODE, key, spec);
>                 cipher.updateAAD(associatedData);
>     
>                 return new String(cipher.doFinal(Base64.getDecoder().decode(ciphertext)), "utf-8");
>             } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
>                 throw new IllegalStateException(e);
>             } catch (InvalidKeyException | InvalidAlgorithmParameterException e) {
>                 throw new IllegalArgumentException(e);
>             }
>         }
>     }

# 7.下单的controller #

>     package com.example.demo.zhifu;
>     
>     import cn.hutool.json.JSONObject;
>     import cn.hutool.json.JSONUtil;
>     import org.springframework.web.bind.annotation.*;
>     import java.nio.charset.StandardCharsets;
>     import java.util.HashMap;
>     import java.util.Map;
>     
>     /**
>      * @Description:
>      * @Author sk
>      * @Date: 2023/7/5 19:10
>      */
>     @RestController
>         @RequestMapping(value = "/pay")
>     public class payController {
>     
>     
>     
>         /**
>          * 预支付下单
>          * @param orderSn 订单号
>          * @param total 分
>          * @param description 描述
>          * @return
>          */
>         @GetMapping(value = "/getPay")
>         public String getPay(String orderSn,int total , String description)
>         {
>             PayUtil payUtil = new PayUtil();
>             try {
>                 return payUtil.requestwxChatPay(orderSn, total, description, "oYgFI91D00GpCwccdnKDR4KNxI4k");
>             } catch (Exception e) {
>                 throw new RuntimeException(e);
>             }
>     
>         }
>     
>         // 支付回调
>         @PostMapping(value = "/returnNotify")
>         public Map returnNotify(@RequestBody JSONObject jsonObject)
>         {
>             // v3 私钥
>             String key = "xxxxx";
>             String json = jsonObject.toString();
>             String associated_data = (String) JSONUtil.getByPath(JSONUtil.parse(json), "resource.associated_data");
>             String ciphertext = (String) JSONUtil.getByPath(JSONUtil.parse(json), "resource.ciphertext");
>             String nonce = (String) JSONUtil.getByPath(JSONUtil.parse(json), "resource.nonce");
>             try {
>                 String decryptData = new AesUtil(key.getBytes(StandardCharsets.UTF_8)).decryptToString(associated_data.getBytes(StandardCharsets.UTF_8), nonce.getBytes(StandardCharsets.UTF_8), ciphertext);
>                 System.out.println("decryptData = " + decryptData);
>                 //TODO 业务校验
>     
>             } catch (Exception e) {
>                 e.printStackTrace();
>             }
>     
>             HashMap<String, String> stringStringHashMap = new HashMap<>();
>             stringStringHashMap.put("code","200");
>             stringStringHashMap.put("message","返回成功");
>             // 返回这个说明应答成功
>             return stringStringHashMap;
>         }
>     
>     }

# 8.官方文档： #

[简介-接口规则 | 微信支付商户平台文档中心][-_ _]

[https_blog.csdn.net_qq_26112725_article_details_131684591]: https://blog.csdn.net/qq_26112725/article/details/131684591
[44ce6b79061943038deae8091cf7e087.png]: https://img-blog.csdnimg.cn/44ce6b79061943038deae8091cf7e087.png
[e215ad3e485c41948516b21db0454dbf.png]: https://img-blog.csdnimg.cn/e215ad3e485c41948516b21db0454dbf.png
[353dccc71a18461ea59ff890ff081d4b.png]: https://img-blog.csdnimg.cn/353dccc71a18461ea59ff890ff081d4b.png
[bb485ad4bd2e4018a7e4eab0dddb767e.png]: https://img-blog.csdnimg.cn/bb485ad4bd2e4018a7e4eab0dddb767e.png
[28fc165bfdcb4540895fa84db76897d2.png]: https://img-blog.csdnimg.cn/28fc165bfdcb4540895fa84db76897d2.png
[-_ _]: https://pay.weixin.qq.com/wiki/doc/apiv3/wechatpay/wechatpay-1.shtml