A summary of Feign FAQ in Spring Cloud.

FeignClient interface. Combined annotations such as @gettingMapping cannot be used

Code examples:

@requestMapping (value = “/simple/{id}”, method = requestmethod.get) cannot be @getMapping (“/simple/{id}”).

In the FeignClient interface, if @PathVariable is used, its value must be specified

Code examples:

The “ID” in @PathVariable(“id”) cannot be omitted, it must be specified.

FeignClient multi-parameter construction

If you want to request the microservice-provider-user service with multiple parameters, for example, http://microservice-provider-user/query-by? If id=1 and username= 1

Using complex objects directly:

The request will not succeed, as long as the parameters are complex objects, feign will still send the request as POST even if GET is specified.

Correct way to write it:

Method 1:

Method 2:

Feign needs to do something extra if it wants to use Hystrix Stream

@feignClient (value = “microservice-provider-user”, fallback = xxx. class); This fallback class integrates the interface annotated by @FeignClient.

But suppose we need to use Hystrix Stream monitor, by default, http://IP:PORT/hystrix.stream is a 404. How do you add Hystrix Stream support to Feign?

The following two steps are required:

Step 1: Add a dependency. Example:

Step 2: Add the @enablecircuitbreaker annotation to the startup class, as in:

After such modifications, following a visit to any API, visit http://IP:PORT/hystrix.stream again, will show a lot of API monitoring data.

If you need to customize a single Feign Configuration, Feign’s @Configuration annotation class cannot overlap with the @ComponentScan package

If packages overlap, this will cause all Feign Clients to use this configuration.

First request failed

Note the @feignClient property

(1) The serviceId attribute is invalid. Try to use the name attribute. Such as:

It is not recommended to write:

(2) When using URL attributes, in the old version of Spring Cloud, there is no need to provide the name attribute, but in the new version (such as Brixton, Camden) @feignClient must provide the name attribute, and the name and URL attributes support placeholders. Such as:

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