Spring Cloud系列（二十二） Spring Cloud Feign配置详解（Finchley.RC2版本）

比眉伴天荒 2022-05-13 10:46 253阅读 0赞

--------------------

**版本说明**

<parent>
    	<groupId>org.springframework.boot</groupId>
    	<artifactId>spring-boot-starter-parent</artifactId>
    	<version>2.0.2.RELEASE</version>
    	<relativePath /> 
    </parent>
    
    <properties>
    	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    	<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    	<java.version>1.8</java.version>
    	<spring-cloud.version>Finchley.RC2</spring-cloud.version>
    </properties>

--------------------

> **Ribbon配置**

**全局配置**

在application.properties中使用ribbon.<key>=<value>的方式来设置ribbon的各项默认参数。比如：

# 设置连接超时时间
    ribbon.ConnectTimeout=500
    # 设置读取超时时间
    ribbon.ReadTimeout=2000

**指定服务配置**

在使用Spring Cloud Feign的时候，针对各个服务客户端进行个性化配置的方式与使用Spring Cloud Ribbon时的配置方式一样，都采用<client>.ribbon.<key>=<value>的格式进行设置，而<client>指代的Ribbon客户端就是我们使用@FeignClient注解的name或value属性，即服务名。

# 设置针对hello-service服务的连接超时时间
    hello-service.ribbon.ConnectTimeout=500
    # 设置针对hello-service服务的读取超时时间
    hello-service.ribbon.ReadTimeout=2000

**重试机制**

Spring Cloud Feign默认实现了重试机制，默认重试5次，通过以下配置来配置相关属性。

# 设置针对hello-service服务的连接超时时间
    hello-service.ribbon.ConnectTimeout=500
    # 设置针对hello-service服务的读取超时时间
    hello-service.ribbon.ReadTimeout=2000
    # 设置针对hello-service服务所有操作请求都进行重试
    hello-service.ribbon.OkToRetryOnAllOperations=true
    # 设置针对hello-service服务切换实例的重试次数
    hello-service.ribbon.MaxAutoRetriesNextServer=2
    # 设置针对hello-service服务的当前实例的重试次数
    hello-service.ribbon.MaxAutoRetries=1
    # 设置断路器超时时间
    hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=2001

相关配置的说明

<table> 
 <thead> 
  <tr> 
   <th>配置</th> 
   <th>说明</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds</td> 
   <td>断路器的超时时间需要大于ribbon的超时时间，不然不会触发重试。</td> 
  </tr> 
  <tr> 
   <td>hello-service.ribbon.ConnectTimeout</td> 
   <td>请求连接的超时时间</td> 
  </tr> 
  <tr> 
   <td>hello-service.ribbon.ReadTimeout</td> 
   <td>请求处理的超时时间</td> 
  </tr> 
  <tr> 
   <td>hello-service.ribbon.OkToRetryOnAllOperations</td> 
   <td>是否对所有操作请求都进行重试</td> 
  </tr> 
  <tr> 
   <td>hello-service.ribbon.MaxAutoRetriesNextServer</td> 
   <td>重试负载均衡其他的实例最大重试次数，不包括首次server，所有的提供者都重试失败，则返回失败</td> 
  </tr> 
  <tr> 
   <td>hello-service.ribbon.MaxAutoRetries</td> 
   <td>同一台实例最大重试次数，不包括首次调用</td> 
  </tr> 
 </tbody> 
</table>

注意：断路器的超时时间和ribbon的超时时间是两个不同的概念，断路器的超时时间必须大于ribbon的超时时间，不然不会触发重试，因为断路器会直接熔断。

**Feign重试和Ribbon重试**

二者的重试机制相互独立，并无联系。但是因为用了feign肯定会用到ribbon，所以feign的重试机制相对来说比较鸡肋。另外，很重要的一点，不论是Feign重试还是Ribbon重试，如果开启了请求重试机制，对于get请求不会有太大的问题，但是对于post或者put请求就可能出现不可预计的后果。比如接口没有做幂等性，类似于对于一次订单支付过程，如果用户重复多次点击支付按钮，或者是网络异常导致订单已经支付成功了但没有及时反馈给用户，用户再次点击支付按钮，就可能造成重复扣款，造成严重后果。所以建议慎重设置这个参数，我建议关闭Feign重试和Ribbon重试，并且服务接口做幂等性等处理。

如果开启的话，建议合理配置Hystrix的超时时间，在一些没必要的重试请求执行时，根据Hystrix的超时时间，快速失败，结束重试。

**测试**

**第一步**，修改hello-service服务，也就是eureka-client-vFinchley.Rc2工程，修改FeignController，添加一个API，并让它随机睡眠0-3000ms

@GetMapping("hello")
    public String hello(){
    	System.out.println("hello");
    	try {
    		//休眠0-3000ms
    		int sleepTime = new Random().nextInt(3000);
    		Thread.sleep(sleepTime);
    		System.out.println(sleepTime);
    	} catch (InterruptedException e) {
    		// TODO Auto-generated catch block
    		e.printStackTrace();
    	}
    	return "hello";
    }

**第二步**，修改feign-consumer服务，即feign-consumer-vFinchley.RC2工程，修改HelloService，添加对上面API的服务调用。

@GetMapping("feign/hello")
    String testRetry();

**第三步**，修改FeignConsumerController，添加对testRetry()的调用

@GetMapping("testRetry")
    public String testRetry(){
    	return helloService.testRetry();
    }

**第四步**，修改application.yml配置文件，配置Feign的重试机制

spring:
      application:
        name: feign-consumer #为服务命名
    server:
      port: 5001
    eureka:
      client:
        service-url: 
          defaultZone: http://localhost:1111/eureka/ #指定服务注册中心位置
      instance:
        prefer-ip-address: true
        instance-id: ${spring.cloud.client.ip-address}:${server.port}
    hello-service:
      ribbon:
        # 配置首台服务器重试1次
        MaxAutoRetries: 1
        # 配置其他服务器重试两次
        MaxAutoRetriesNextServer: 2
        # 连接超时时间
        ConnectTimeout: 500
        # 请求处理时间
        ReadTimeout: 2000
        # 每个操作都开启重试机制
        OkToRetryOnAllOperations: true
    
    # 配置断路器超时时间，默认是1000（1秒）
    hystrix:
      command:
        default:
          execution:
            isolation:
              thread:
                timeoutInMilliseconds: 2001

启动服务注册中心，即eureka-server-vFinchley.Rc2工程

启动服务提供者hello-service，即eureka-client-vFinchley.Rc2 工程

启动服务消费者feign-consumer，即feign-consumer-vFinchley.RC2工程

请求[localhost:5001/testRetry][localhost_5001_testRetry],直到遇见服务超时即可。

![70][]

可以看到我划线部分，第一次请求延迟时间为2628毫秒，请求超时，Feign客户端发起了请求重试，第二次请求延迟为1553毫秒，没有超时。Feign客户端在进行服务调用时经历了一次失败，但是通过重试机制，最终还是获得了请求结果。

> **Hystrix配置**

**全局配置**

对于Hystrix的全局配置同Spring Cloud Ribbon的全局配置一样，直接使用它的默认配置前缀hystrix.command.default就可以进行设置，比如设置全局的超时时间

# 设置熔断超时时间
    hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=2000

**指定命令配置**

配置方法和传统的Hystrix命令的参数配置相似，采用hystrix.command.<commandKey>作为前缀。而<commandKey>默认情况下会采用Feign客户端中的方法名作为标识，所以针对上一节重试机制中对/feign/hello接口的熔断超时时间的配置可以通过其方法名作为<commandKey>来进行配置，比如：

hystrix.command.testRetry.execution.isolation.thread.timeoutInMilliseconds=1000

在使用指定命令配置的时候，需要注意，由于方法名很有可能重复，这个时候相同方法名的Hystrix配置会共用，所以尽量避免方法重名。当然，也可以重写Feign.Builder的实现，并在应用主类中创建它的实例来覆盖自动化配置的HystrixFeign.Builder实现。

**禁用Hystrix**

1.全局配置

# 关闭Hystrix功能
    feign.hystrix.enabled=false
    # 关闭熔断功能
    hystrix.command.default.execution.timeout.enabled=false

2.针对某个服务禁用Hystrix

**第一步**，构建一个关闭Hystrix的配置类

@Configuration
    public class DisabledHystrixConfiguration {
    
    	@Bean
    	@Scope("prototype")
    	public Feign.Builder feignBuilder(){
    		return Feign.builder();
    	}
    }

**第二步**，在需要关闭Hystrix功能的Feign客户端的服务绑定接口类，通过@FeignClient注解的configuration属性指定

@FeignClient(value = "hello-service", fallback = HelloServiceFallback.class, configuration = {DisabledHystrixConfiguration.class })
    public interface HelloService {
    
    	@GetMapping("hello")
    	String hello();
    
    	@GetMapping("feign/hello1")
    	public User hello1(@RequestParam("name") String name, @RequestParam("age") int age);
    
    	@GetMapping("feign/hello2")
    	public User hello2(@RequestHeader("name") String name, @RequestHeader("age") int age);
    
    	@PostMapping("feign/hello3")
    	public User hello3(@RequestBody User user);
    
    	@GetMapping("feign/hello")
    	String testRetry();
    }

此时全局的Hystrix是开启的，只是关闭了HelloService的Hystrix功能。

**服务降级配置**

**第一步**，为Feign客户端的定义接口编写一个具体的接口实现类，并重写每个方法的服务降级逻辑。

@Component//此注解不加无法扫描到这个类
    public class HelloServiceFallback implements HelloService{
    
    	@Override
    	public String hello() {
    		return "error";
    	}
    
    	@Override
    	public User hello1(String name, int age) {
    		return new User(1,"error",1);
    	}
    
    	@Override
    	public User hello2(String name, int age) {
    		// TODO Auto-generated method stub
    		return new User(1,"error",1);
    	}
    
    	@Override
    	public User hello3(User user) {
    		// TODO Auto-generated method stub
    		return new User(1,"error",1);
    	}
    
    	@Override
    	public String testRetry() {
    		// TODO Auto-generated method stub
    		return "error";
    	}
    
    }

**第二步**，在服务绑定接口中通过@FeignClient注解的fallback属性指定对应的服务降级实现类。

@FeignClient(value="hello-service",fallback=HelloServiceFallback.class)
    public interface HelloService {
    
    	@GetMapping("hello")
    	String hello();
    	
    	@GetMapping("feign/hello1")
    	public User hello1(@RequestParam("name") String name,@RequestParam("age") int age);
    	
    	@GetMapping("feign/hello2")
    	public User hello2(@RequestHeader("name") String name,@RequestHeader("age") int age);
    	
    	@PostMapping("feign/hello3")
    	public User hello3(@RequestBody User user);
    	
    	@GetMapping("feign/hello")
    	String testRetry();
    }

**测试**

只启动服务注册中心和服务消费者feign-consumer，即feign-consumer-vFinchley.RC2，不启动服务提供者hello-service。

访问[http://localhost:5001/hello1][http_localhost_5001_hello1]，结果说明直接触发了服务降级。

User [id=1, name=error, age=1]
    User [id=1, name=error, age=1] 
    User [id=1, name=error, age=1]

注意：feign.hystrix.enabled默认值为false，Feign默认关闭Hystrix熔断功能，需要先通过feign.hystrix.enabled=true配置开启。

> **其他配置**

**请求压缩**

Spring Cloud Feign支持对请求与响应进行GZIP压缩，以减少通信过程中的性能损耗，只需要下面两个参数设置就可以开启请求与响应的压缩功能。

# 配置请求GZIP压缩
    feign.compression.request.enabled=true
    # 配置响应GZIP压缩
    feign.compression.response.enabled=true

Spring Cloud Feign也对请求压缩支持更细致的设置。

# 配置请求GZIP压缩
    feign.compression.request.enabled=true
    # 配置压缩支持的MIME TYPE 默认值text/xml,application/xml,application/json
    feign.compression.request.mime-types=text/xml,application/xml,application/json
    # 配置压缩数据大小的下限 默认值2048
    feign.compression.request.min-request-size=2048

> **日志配置**

Spring Cloud Feign在构建被@FeignClient注解修饰的服务客户端时，会为每一个客户端都创建一个feign.Logger实例，我们可以利用该日志对象的DEBUG模式来帮助分析Feign的请求细节。可以使用logging.level.<FeignClient>的参数配置格式来指定Feign客户端的DEBUG日志，其中<FeignClient>为客户端定义接口的完整路径，比如对于HelloService可以这么配置

logging.level.com.wya.springboot.service.HelloService=DEBUG

在application.yml文件中这样设置

logging:
      level:
        com:
          wya:
            springboot:
              service:
                HelloService: DEBUG

我的版本就可以直接输出日志了，老版本的话这样还不能实现对DEBUG日志的输出，因为Feign客户端默认的logging.level对象定义为NONE级别，该级别不会记录Feign调用过程中的信息，我们需要调整它的级别。

对于全局的日志级别，在主类直接加入Logger.Level的Bean创建

@EnableFeignClients
    @EnableDiscoveryClient
    @SpringBootApplication
    public class Application {
    	
    	@Bean
    	Logger.Level feignLoggerLevel(){
    		return Logger.Level.FULL;
    	}
    
    	public static void main(String[] args) {
    		SpringApplication.run(Application.class, args);
    	}
    }

对于不同的Feign客户端指定配置类可以通过实现配置类来调整日志级别。

@Configuration
    public class FullLoggerConfiguration{
    	
    	@Bean
    	Logger.Level feignLoggerLevel(){
    		return Logger.Level.FULL;
    	}
    
    }

然后通过@FeignClient注解的configuration属性指定。

@FeignClient(value="hello-service",fallback=HelloServiceFallback.class,configuration={FullLoggerConfiguration.class})
    public interface HelloService {
    
    	@GetMapping("hello")
    	String hello();
    	
    	@GetMapping("feign/hello1")
    	public User hello1(@RequestParam("name") String name,@RequestParam("age") int age);
    	
    	@GetMapping("feign/hello2")
    	public User hello2(@RequestHeader("name") String name,@RequestHeader("age") int age);
    	
    	@PostMapping("feign/hello3")
    	public User hello3(@RequestBody User user);
    	
    	@GetMapping("feign/hello")
    	String testRetry();
    }

再次请求[http://localhost:5001/hello1][http_localhost_5001_hello1]接口我们就可以看到控制台打印请求的详细信息。

2018-09-12 15:48:07.170  INFO 9036 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Disable delta property : false
    2018-09-12 15:48:07.171  INFO 9036 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Single vip registry refresh property : null
    2018-09-12 15:48:07.171  INFO 9036 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Force full registry fetch : false
    2018-09-12 15:48:07.171  INFO 9036 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Application is null : false
    2018-09-12 15:48:07.171  INFO 9036 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Registered Applications size is zero : true
    2018-09-12 15:48:07.171  INFO 9036 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Application version is -1: false
    2018-09-12 15:48:07.171  INFO 9036 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient    : Getting all instance registry info from the eureka server
    2018-09-12 15:48:07.222  INFO 9036 --- [freshExecutor-0] com.netflix.discovery.DiscoveryClient    : The response status is 200
    2018-09-12 15:48:08.349  INFO 9036 --- [nio-5001-exec-2] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
    2018-09-12 15:48:08.349  INFO 9036 --- [nio-5001-exec-2] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
    2018-09-12 15:48:08.366  INFO 9036 --- [nio-5001-exec-2] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 17 ms
    2018-09-12 15:48:08.578 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] ---> GET http://hello-service/feign/hello1?name=test1&age=22 HTTP/1.1
    2018-09-12 15:48:08.578 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] ---> END HTTP (0-byte body)
    2018-09-12 15:48:08.580  INFO 9036 --- [hello-service-1] s.c.a.AnnotationConfigApplicationContext : Refreshing SpringClientFactory-hello-service: startup date [Wed Sep 12 15:48:08 CST 2018]; parent: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@1fde5d22
    2018-09-12 15:48:08.638  INFO 9036 --- [hello-service-1] f.a.AutowiredAnnotationBeanPostProcessor : JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
    2018-09-12 15:48:08.846  INFO 9036 --- [hello-service-1] c.netflix.config.ChainedDynamicProperty  : Flipping property: hello-service.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
    2018-09-12 15:48:08.865  INFO 9036 --- [hello-service-1] c.n.u.concurrent.ShutdownEnabledTimer    : Shutdown hook installed for: NFLoadBalancer-PingTimer-hello-service
    2018-09-12 15:48:08.886  INFO 9036 --- [hello-service-1] c.netflix.loadbalancer.BaseLoadBalancer  : Client: hello-service instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=hello-service,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
    2018-09-12 15:48:08.892  INFO 9036 --- [hello-service-1] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
    2018-09-12 15:48:08.917  INFO 9036 --- [hello-service-1] c.netflix.config.ChainedDynamicProperty  : Flipping property: hello-service.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
    2018-09-12 15:48:08.918  INFO 9036 --- [hello-service-1] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client hello-service initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=hello-service,current list of Servers=[192.168.1.227:2222],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone;	Instance count:1;	Active connections count: 0;	Circuit breaker tripped count: 0;	Active connections per server: 0.0;]
    },Server stats: [[Server:192.168.1.227:2222;	Zone:defaultZone;	Total Requests:0;	Successive connection failure:0;	Total blackout seconds:0;	Last connection made:Thu Jan 01 08:00:00 CST 1970;	First connection made: Thu Jan 01 08:00:00 CST 1970;	Active Connections:0;	total failure count in last (1000) msecs:0;	average resp time:0.0;	90 percentile resp time:0.0;	95 percentile resp time:0.0;	min resp time:0.0;	max resp time:0.0;	stddev resp time:0.0]
    ]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@58287100
    2018-09-12 15:48:09.193 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] <--- HTTP/1.1 200 (614ms)
    2018-09-12 15:48:09.193 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] content-type: application/json;charset=UTF-8
    2018-09-12 15:48:09.193 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] date: Wed, 12 Sep 2018 07:48:09 GMT
    2018-09-12 15:48:09.193 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] transfer-encoding: chunked
    2018-09-12 15:48:09.193 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] 
    2018-09-12 15:48:09.207 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] {"id":1,"name":"test1","age":22}
    2018-09-12 15:48:09.208 DEBUG 9036 --- [hello-service-1] com.wya.springboot.service.HelloService  : [HelloService#hello1] <--- END HTTP (32-byte body)
    2018-09-12 15:48:09.246 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] ---> GET http://hello-service/feign/hello2 HTTP/1.1
    2018-09-12 15:48:09.246 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] name: test2
    2018-09-12 15:48:09.246 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] age: 22
    2018-09-12 15:48:09.246 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] ---> END HTTP (0-byte body)
    2018-09-12 15:48:09.268 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] <--- HTTP/1.1 200 (21ms)
    2018-09-12 15:48:09.269 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] content-type: application/json;charset=UTF-8
    2018-09-12 15:48:09.269 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] date: Wed, 12 Sep 2018 07:48:09 GMT
    2018-09-12 15:48:09.269 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] transfer-encoding: chunked
    2018-09-12 15:48:09.269 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] 
    2018-09-12 15:48:09.270 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] {"id":2,"name":"test2","age":22}
    2018-09-12 15:48:09.270 DEBUG 9036 --- [hello-service-2] com.wya.springboot.service.HelloService  : [HelloService#hello2] <--- END HTTP (32-byte body)
    2018-09-12 15:48:09.292 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] ---> POST http://hello-service/feign/hello3 HTTP/1.1
    2018-09-12 15:48:09.293 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] Content-Type: application/json;charset=UTF-8
    2018-09-12 15:48:09.293 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] Content-Length: 32
    2018-09-12 15:48:09.293 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] 
    2018-09-12 15:48:09.293 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] {"id":3,"name":"test1","age":22}
    2018-09-12 15:48:09.293 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] ---> END HTTP (32-byte body)
    2018-09-12 15:48:09.346 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] <--- HTTP/1.1 200 (52ms)
    2018-09-12 15:48:09.346 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] content-type: application/json;charset=UTF-8
    2018-09-12 15:48:09.346 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] date: Wed, 12 Sep 2018 07:48:09 GMT
    2018-09-12 15:48:09.347 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] transfer-encoding: chunked
    2018-09-12 15:48:09.347 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] 
    2018-09-12 15:48:09.347 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] {"id":3,"name":"test1","age":22}
    2018-09-12 15:48:09.347 DEBUG 9036 --- [hello-service-3] com.wya.springboot.service.HelloService  : [HelloService#hello3] <--- END HTTP (32-byte body)
    2018-09-12 15:48:09.895  INFO 9036 --- [erListUpdater-0] c.netflix.config.ChainedDynamicProperty  : Flipping property: hello-service.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647

对于Feign的Logger级别有如下四种，可根据实际情况调整。

1.  NONE：不记录任何信息
2.  BASIC：仅记录请求方法、URL以及响应状态码和执行时间
3.  HEADERS：除了记录BASIC级别的信息外，还会记录请求和响应的头信息
4.  FULL：记录所有请求与响应的明细，包括头信息、请求头、元数据等。

> **Feign原理与覆盖默认配置**

推荐阅读：[深入理解Feign之源码解析][Feign]，这里我就不赘述了。

[localhost_5001_testRetry]: http://localhost:5001/testRetry
[70]: /images/20220513/50a4fbbc9fa14817a9c3329674f981ab.png
[http_localhost_5001_hello1]: http://localhost:5001/hello1
[Feign]: https://blog.csdn.net/forezp/article/details/73480304