The method of calling Feign remotely by client
This article introduces the knowledge of "the method of remote calling Feign from the client". Many people will encounter such a dilemma in the operation of actual cases, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!
What is Feign when the client calls Feign remotely?
Feign is Netflix's open source declarative HTTP client
Github: Feign source code
Why do I need Feign?
The readability of the original code is not high
Complex URL is difficult to maintain (https://user-center/s?wd={userId}&rsv_spt=1&rsv_iqid=0x93bff3cd000cf3da&issp=1&f=8&rsv_bp=1&rsv_idx=2&ie=utf-8&tn=baiduhome_pg&rsv_enter=1&rsv_sug3=4&rsv_sug1=4&rsv_sug7=100&rsv_t=10c2risCimsUZC0RBruMerdnQRN1gRxFI%2BywuD0L3LwGGNd2dR8XE6x%2FyFOjHnR0oEi0&rsv_sug2=0&inputT=1535&rsv_sug4=1535&rsv_sug=2)
It is difficult to cope with the rapid changes in demand
The coding experience is quite different from our writing JAVA.
For example, before refactoring code / / replace ResponseEntity userEntity = restTemplate.getForEntity ("http://user-center/users/{userId}", UserDTO.class, userId); UserDTO userDTO = new UserDTO (); if (null! = userEntity) {userDTO = userEntity.getBody () Log.info ("ShareService#findById userDTO: {}", userDTO);}
Add dependency
Org.springframework.cloud spring-cloud-starter-openfeign
Add an annotation to the startup class @ EnableFeignClients
Add configuration
Implement the client of the corresponding microservice
/ * * IUserCenterFeignClient for defines user-center feign client * * @ author Isaac.Zhang | if the beginning * @ since 2019-7-15 * / @ FeignClient (name = "user-center") public interface IUserCenterFeignClient {/ * Feign client will convert the request to * http://user-center/users/{userId} * @ param userId user id * @ return and return the user object * / @ GetMapping (path = "/ users/ {userId}") public UserDTO findById (@ PathVariable Long userId) }
Code after replacement
/ / use FeignClient to replace RestTemplate call UserDTO userDTO = this.userCenterFeignClient.findById (userId); composition of Feign
Configuration of Feign configuration items supported by Java Code
Customize the Feign log level
Level content
Demo
* * Tip * *: the problem of parent-child context overlap may occur
Add configuration in client
/ * * IUserCenterFeignClient for defines user-center feign client * * @ author Isaac.Zhang | if the beginning * @ since 2019-7-15 * / @ FeignClient (name = "user-center", configuration = UserCenterFeignConfiguration.class) public interface IUserCenterFeignClient {.}
Write java configuration file
/ * in the custom user-center service request of UserCenterFeignConfiguration for, the configuration information of feign * {@ link @ Configuration} cannot be added, otherwise, like ribbon, the problem of context overlap will occur, resulting in global sharing of configuration * if you want to add this comment This class needs to be placed under the package that cannot be scanned by the main program * * @ author Isaac.Zhang | if the beginning * @ since 2019-7-15 * / public class UserCenterFeignConfiguration {@ Bean public Logger.Level level () {/ / configure the feign log level, record the header, body and metadata return Logger.Level.FULL of the request and response }}
Be sure to add the client full path to the configuration file
Logging: level: # com.sxzhongf: debug com.sxzhongf.sharedcenter.feignclients.IUserCenterFeignClient: debug
Print information
2019-07-15 15 c.s.s.f.IUserCenterFeignClient 06 DEBUG 11.650 20286-[nio-8010-exec-1] c.s.s.f.IUserCenterFeignClient: [IUserCenterFeignClient#findById]
