3 ways for OpenFeign to set headers

Set the Header information of OpenFeign's FeignClient

When using Feign to make remote calls between microservices, you need to add information in the header, so how do SpringBoot and SpringCloud OpenFeign's @FeignClient set the header?There are 5 ways to set request header information:

• Add headers attribute to @RequestMapping annotation
• Add @RequestHeader annotation in front of method parameters
• Implement RequestInterceptor interface

Since Feign fully supports Spring MVC annotations, it is recommended to use the first two Feign settingsheader method, that is: Spring MVC uses annotations to set headers.

1. Add the headers attribute to the **@RequestMapping** annotation

Configure in application.yml

[email protected](value = "/service/rest/v1/script/{scriptName}/run",headers = {"Authorization=Basic YWRtaW46QFdUTDE5OTIwMTE4MDI3MQ==","Content-Type=text/plain","AppSecret=${my.name}"})String runScript(@PathVariable("scriptName") String scriptName);

2. Add @RequestHeaderannotation

in front of method parameters

• Set a single header property

  @PostMapping(value = "/service/rest/v1/script/{scriptName}/run", headers = {"Content-Type=text/plain","AppSecret=${my.name}"})
  String runScript(@PathVariable("scriptName") String scriptName,@RequestHeader("Authorization") String authorization);

  public StringrunScript(String scriptName) {
  return nexusOpenFeign.runScript(scriptName,“Basic YWRtaW46QFdUTDE5OTIwMTE4MDI3MQ==”);
  }

• Set multiple header properties

  @PostMapping(value = “/service/rest/v1/script/{scriptName}/run”)
  String runScript(@PathVariable(“scriptName”) String scriptName,@RequestHeader MultiValueMap headers);

  public String runScript(String scriptName) {
  MultiValueMap headers = new HttpHeaders();
  headers.put("Authorization", Collections.singletonList("Basic YWRtaW46QFdUTDE5OTIwMTE4MDI3MQ=="));
  headers.add("Content-Type","text/plain");
  return nexusOpenFeign.runScript(scriptName,headers);
  }

3、实现RequestInterceptorInterface

If FeignRequestInterceptor is injected into the spring container, it will take effect globally, that is to say, the configuration will take effect even in FeignClient that does not specify the configuration attribute.
By configuring @Component or @Service or @Configuration, the configuration can be injected into the spring container, and the global configuration can be implemented, so that all FeignClient feign interfaces in the project can use this configuration.
If you only want toUse this configuration for the feign interface that specifies FeignClient, do not inject this configuration into spring.

@Configurationpublic class FeignRequestInterceptor implements RequestInterceptor {@Overridepublic void apply(RequestTemplate template) {template.header(HttpHeaders.AUTHORIZATION, "tokenVal");}}@FeignClient(url = "${user.api.url}", name = "user", configuration = FeignRequestInterceptor.class)public interface UserFeignClient {@GetMapping(value = "/simple/{id}")public User findById(@RequestParam("id") String id);}

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