🎨 #3738 【微信支付】修复V3新商户完全公钥模式下publicKey为空的问题

Author: Copilot

weixin-java-pay/src/main/java/com/github/binarywang/wxpay/config/WxPayConfig.java

@@ -377,6 +377,9 @@ public CloseableHttpClient initApiV3HttpClient() throws WxPayException {
       Verifier certificatesVerifier;
       if (this.fullPublicKeyModel) {
         // 使用完全公钥模式时，只加载公钥相关配置，避免下载平台证书使灰度切换无法达到100%覆盖
+        if (publicKey == null) {
+          throw new WxPayException("完全公钥模式下，请确保公钥配置（publicKeyPath/publicKeyString/publicKeyContent）及publicKeyId已设置");
+        }
         certificatesVerifier = VerifierBuilder.buildPublicCertVerifier(this.publicKeyId, publicKey);
       } else {
         certificatesVerifier = VerifierBuilder.build(