@SentinelResource ,how enable blockHandlerClass ,fallbackClass

[IvesQing]

Issue Description

Describe what you expected to happen

how enabled blockHandlerClass ,fallbackClass

How to reproduce it (as minimally and precisely as possible)

Tell us your environment

1、sentinel 1.8.3 2、springcloudalibaba 2021.0.1.0

[sczyh30]

blockHandler 名称没有配置，具体参考文档：https://sentinelguard.io/zh-cn/docs/annotation-support.html