Feign：服务挂了也不会走fallback

Feign 本质上是一个 HTTP 客户端，用于简化微服务之间的 HTTP 通信。它允许开发者通过定义接口和注解来声明式地编写 HTTP 客户端，而无需手动编写 HTTP 请求和响应处理的代码。

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今天在模拟微服务A feign调用微服务B的时候，把微服务B关了，可是调用的时候不会走fallback降级方法。直接报错：

2024-09-28 18:45:00.247 ERROR 13248 --- [illProductJob-2] c.d.d.j.e.h.i.DefaultJobExceptionHandler : Job 'InitSeckillProductJob' exception occur in job processing

java.lang.RuntimeException: com.netflix.client.ClientException: Load balancer does not have available server for client: seckill-service
	at org.springframework.cloud.openfeign.ribbon.LoadBalancerFeignClient.execute(LoadBalancerFeignClient.java:90) ~[spring-cloud-openfeign-core-2.2.5.RELEASE.jar:2.2.5.RELEASE]
	at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:119) ~[feign-core-10.10.1.jar:na]
	at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:89) ~[feign-core-10.10.1.jar:na]
	at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:100) ~[feign-core-10.10.1.jar:na]
	at com.sun.proxy.$Proxy76.queryByTimeForJob(Unknown Source) ~[na:na]
	at cn.dscode.job.InitSeckillProductJob.execute(InitSeckillProductJob.java:38) ~[classes/:na]
	at com.dangdang.ddframe.job.executor.type.SimpleJobExecutor.process(SimpleJobExecutor.java:41) ~[elastic-job-common-core-2.1.5.jar:na]
	at com.dangdang.ddframe.job.executor.AbstractElasticJobExecutor.process(AbstractElasticJobExecutor.java:206)