解决OpenFeign调用时抛出 PKIX path building failed 证书异常

网上大部分解决方案都是，自定义注入Client.Default，传入一个忽略SSL证书的SSLSocketFactory

但这样是有问题的，如果feignclient的url未指定时，client的实现是RetryableFeignBlockingLoadBalancerClient, 你先前注入的Client.Default就会影响需要服务发现的相关逻辑

我们可以实现个一个FeignBuilderCustomizer，来解决以上问题

@Bean
public FeignBuilderCustomizer feignBuilderCustomizer() {
    return b -> {
        try {
            Class<Feign.Builder> builderClass = Feign.Builder.class;
            Field client = builderClass.getDeclaredField("client");
            client.setAccessible(true);
            Object field = ReflectionUtils.getField(client, b);

            // 判断是否是默认的Client, 如果是默认的实现，说明指定了url, 替换成忽略ssl的默认实现
            if( field instanceof Client.Default) {
                b.client(feignClient());
            }

        }catch(Exception e){
            log.error("使用FeignBuilderCustomizer异常: {}", e.getMessage(), e);
        }
    };
}


public Client feignClient() {
    return new Client.Default(getSslSocketFactory(), new NoopHostnameVerifier());
}

private SSLSocketFactory getSslSocketFactory() {
    try {
        SSLContext sslContext = SSLContexts.custom().loadTrustMaterial(null, new TrustSelfSignedStrategy()).build();
        return sslContext.getSocketFactory();
    } catch (Exception ex) {
        throw new RuntimeException(ex);
    }
}