# 商户ID
wxpay.mch-id=xxxxx
# 商户平台号
wxpay.mch-serial-no=xxxxx
# 商户证书
wxpay.private-key-path=wechat/apiclient_key.pem
# 微信平台证书
wxpay.platformCertPath=wechat/wechatpay_2694B2E0B2719A25EE1063EE02CFC78EE035E8CF.pem
# 下载地址参考: https://github.com/wechatpay-apiv3/CertificateDownloader
# 商户api v3
wxpay.api-v3-key=xxxxx
# 小程序appid
wxpay.appid=xxxxx
# 小程序密钥
wxpay.secret=xxxxx
wxpay.domain=https://api.mch.weixin.qq.com
# 本地使用内网穿透代理回调
wxpay.notify-domain=https://x x x x x x x x x x x x/wx-api
# 商户apiv2
wxpay.partner-key=xxxxxxxxxxxxx

java -jar CertificateDownloader.jar -k ${apiV3key} -m ${mchId} -f ${mchPrivateKeyFilePath} -s ${mchSerialNo} -o ${outputFilePath}
示例：
java -jar CertificateDownloader-1.2.0-jar-with-dependencies.jar 
-k=商户v3key 
-m=商户ID 
-f=/Users/yangbuyi/Documents/workPath/workPath/wx-play-demo/src/main/resources/apiclient_key.pem 
-s=商户证书序列号 
-o=/Users/yangbuyi/Documents/workPath/workPath/wx-play-demo/src/main/resources
解释：
java -jar CertificateDownloader-1.2.0-jar-with-dependencies.jar 
-k=这是对应配置文件当中的 APIV3Key（wxpay.api-v3-key）商户APIV3Key
-m=这是对应配置文件当中的 mchID （wxpay.mch-id） 商户ID 
-f=这是对应配置文件当中到 商户证书 apiclient_key.pem  （绝对路径地址）
-s=这是对应配置文件当中的 mchSerialNo（wxpay.mch-serial-no）商户平台证书序列号
-o=这是将生成的文件输出到哪个目录下面 （绝对路径地址）

package com.yby6.config;
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.ScheduledUpdateCertificatesVerifier;
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.util.PemUtil;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.apache.http.impl.client.CloseableHttpClient;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.security.PrivateKey;
@Configuration
@PropertySource("classpath:wechat/wxpay.properties") //读取配置文件
@ConfigurationProperties(prefix = "wxpay") //读取wxpay节点
@Data //使用set方法将wxpay节点中的值填充到当前类的属性中
@Slf4j
public class WxPayConfig {
    // 商户号
    private String mchId;
    // 商户API证书序列号
    private String mchSerialNo;
    // 商户私钥文件
    private String privateKeyPath;
    // 微信平台证书
    private String platformCertPath;
    // APIv3密钥
    private String apiV3Key;
    // APPID
    private String appid;
    // app secret
    private String secret;
    // 微信服务器地址
    private String domain;
    // 接收结果通知地址
    private String notifyDomain;
    // APIv2密钥
    private String partnerKey;
    /**
     * 获取商户的私钥文件
     */
    public PrivateKey getPrivateKey(String filename) {
        try {
            InputStream inputStream = getClass().getClassLoader().getResourceAsStream(filename);
            if (inputStream == null) {
                throw new FileNotFoundException("私钥文件不存在");
            }
            return PemUtil.loadPrivateKey(inputStream);
        } catch (Exception e) {
            throw new RuntimeException("私钥文件不存在", e);
        }
    }
    /**
     * 获取签名验证器
     */
    @Bean
    public ScheduledUpdateCertificatesVerifier getVerifier() {
        log.info("构建签名验证器");
        log.info("mchId: {}", mchId);
        log.info("mchSerialNo: {}", mchSerialNo);
        log.info("privateKeyPath: {}", privateKeyPath);
        log.info("apiV3Key: {} , {}", apiV3Key , apiV3Key.length());
        log.info("appid: {}", appid);
        log.info("domain: {}", domain);
        log.info("notifyDomain: {}", notifyDomain);
        log.info("partnerKey: {} , {}", partnerKey , partnerKey.length());
        //获取商户私钥
        PrivateKey privateKey = getPrivateKey(privateKeyPath);
        //私钥签名对象
        PrivateKeySigner privateKeySigner = new PrivateKeySigner(mchSerialNo, privateKey);
        //身份认证对象
        WechatPay2Credentials wechatPay2Credentials = new WechatPay2Credentials(mchId, privateKeySigner);
        // 使用定时更新的签名验证器，不需要传入证书 -> 它会帮助我们下载最新的证书不会进行过期
        return new ScheduledUpdateCertificatesVerifier(wechatPay2Credentials, apiV3Key.getBytes(StandardCharsets.UTF_8));
    }
    /**
     * 获取http请求对象
     */
    @Bean(name = "wxPayClient")
    public CloseableHttpClient getWxPayClient(ScheduledUpdateCertificatesVerifier verifier) {
        log.info("获取httpClient");
        //获取商户私钥
        PrivateKey privateKey = getPrivateKey(privateKeyPath);
        WechatPayHttpClientBuilder builder = WechatPayHttpClientBuilder.create()
                // 设置商户信息
                .withMerchant(mchId, mchSerialNo, privateKey)
                // 设置验签器
                .withValidator(new WechatPay2Validator(verifier));
        // ... 接下来，你仍然可以通过builder设置各种参数，来配置你的HttpClient
        // 通过WechatPayHttpClientBuilder构造的HttpClient，会自动的处理签名和验签，并进行证书自动更新
        return builder.build();
    }
    /**
     * 获取HttpClient，无需进行应答签名验证，跳过验签的流程
     */
    @Bean(name = "wxPayNoSignClient")
    public CloseableHttpClient getWxPayNoSignClient() {
        //获取商户私钥
        PrivateKey privateKey = getPrivateKey(privateKeyPath);
        //用于构造HttpClient
        WechatPayHttpClientBuilder builder = WechatPayHttpClientBuilder.create()
                //设置商户信息
                .withMerchant(mchId, mchSerialNo, privateKey)
                //无需进行签名验证、通过withValidator((response) -> true)实现
                .withValidator((response) -> true);
        // 通过WechatPayHttpClientBuilder构造的HttpClient，会自动的处理签名和验签，并进行证书自动更新
        CloseableHttpClient httpClient = builder.build();
        log.info("== getWxPayNoSignClient END ==");
        return httpClient;
    }
}

package com.yby6.controller;
import cn.hutool.json.JSONUtil;
import com.yby6.config.WxPayConfig;
import com.yby6.service.WxPayService;
import lombok.RequiredArgsConstructor;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
 * @author Yang Shuai
 * Create By 2023/6/8
 */
@RestController
@RequestMapping
@RequiredArgsConstructor
public class WechatController {
    private final WxPayConfig wxPayConfig;
    @GetMapping("/index")
    public String index() {
        return "ok";
    }
    @PostMapping("getMchId")
    public Object getMchId() {
        return wxPayConfig.getMchId();
    }
}

package com.yby6;
import cn.hutool.core.util.ArrayUtil;
import com.yby6.config.WxPayConfig;
import jakarta.annotation.Resource;
import org.apache.http.impl.client.CloseableHttpClient;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import java.security.PrivateKey;
import java.time.Duration;
import java.time.Instant;
@SpringBootTest
class WxPlayDemoApplicationTests {
    @Resource
    private WxPayConfig wxPayConfig;
    @Resource
    private CloseableHttpClient wxPayClient;
    @Resource
    private CloseableHttpClient wxPayNoSignClient;
    /**
     * 获取商户的私钥
     */
    @Test
    void testGetPrivateKey() {
        //获取私钥路径
        String privateKeyPath = wxPayConfig.getPrivateKeyPath();
        //获取私钥
        PrivateKey privateKey = wxPayConfig.getPrivateKey(privateKeyPath);
        System.out.println(privateKey);
        System.out.println(wxPayClient);
        System.out.println(wxPayNoSignClient);
    }
}