淄博网站建设 招聘,做电商能赚钱吗,仿朋友圈网站建设,舞阳专业做网站Eureka 与 Feign 知识解析
1. Eureka
Spring Cloud Eureka 是服务发现组件#xff0c;包含#xff1a;
Eureka Server#xff1a;注册中心#xff0c;管理服务实例Eureka Client#xff1a;服务实例#xff0c;向注册中心注册/获取服务信息
核心功能#xff1a;
服…Eureka 与 Feign 知识解析
1. Eureka
Spring Cloud Eureka 是服务发现组件包含
Eureka Server注册中心管理服务实例Eureka Client服务实例向注册中心注册/获取服务信息
核心功能
服务注册与发现心跳检测默认30秒服务故障自动剔除客户端缓存注册信息
2. OpenFeign
声明式 HTTP 客户端工具核心特性
基于接口的声明式调用整合 Ribbon 实现负载均衡整合 Hystrix 实现熔断需额外配置自动处理 HTTP 请求/响应序列化
依赖关系
!-- Eureka Server --
dependencygroupIdorg.springframework.cloud/groupIdartifactIdspring-cloud-starter-netflix-eureka-server/artifactId
/dependency!-- Eureka Client OpenFeign --
dependencygroupIdorg.springframework.cloud/groupIdartifactIdspring-cloud-starter-netflix-eureka-client/artifactId
/dependency
dependencygroupIdorg.springframework.cloud/groupIdartifactIdspring-cloud-starter-openfeign/artifactId
/dependency完整示例代码
1. Eureka Server (服务注册中心)
application.yml
server:port: 8761
eureka:client:register-with-eureka: falsefetch-registry: falseEurekaServerApplication.java
SpringBootApplication
EnableEurekaServer
public class EurekaServerApplication {public static void main(String[] args) {SpringApplication.run(EurekaServerApplication.class, args);}
}2. Service Provider (服务提供者)
application.yml
server:port: 8081
spring:application:name: user-service
eureka:client:service-url:defaultZone: http://localhost:8761/eureka/UserController.java
RestController
RequestMapping(/users)
public class UserController {GetMapping(/{id})public User getUser(PathVariable Long id) {return new User(id, 用户 id, user id example.com);}
}// 实体类
public class User {private Long id;private String name;private String email;// 构造方法/getters/setters
}3. Service Consumer (服务消费者)
application.yml
server:port: 8080
spring:application:name: order-service
eureka:client:service-url:defaultZone: http://localhost:8761/eureka/Feign Client 接口
FeignClient(name user-service)
public interface UserServiceClient {GetMapping(/users/{id})User getUserById(PathVariable(id) Long userId);// 请求参数示例GetMapping(/users/search)User searchUser(RequestParam(name) String name);
}OrderController.java
RestController
RequestMapping(/orders)
public class OrderController {Autowiredprivate UserServiceClient userServiceClient;GetMapping(/{orderId}/user)public User getOrderUser(PathVariable Long orderId) {// 通过Feign调用用户服务Long userId orderId * 10; // 模拟用户IDreturn userServiceClient.getUserById(userId);}
}启用Feign (主类)
SpringBootApplication
EnableFeignClients
public class OrderServiceApplication {public static void main(String[] args) {SpringApplication.run(OrderServiceApplication.class, args);}
}4. 高级配置
自定义Feign配置
Configuration
public class FeignConfig {BeanLogger.Level feignLoggerLevel() {return Logger.Level.FULL; // 详细日志}Beanpublic RequestInterceptor authInterceptor() {return template - template.header(Authorization, Bearer token123);}
}使用配置
FeignClient(name user-service,configuration FeignConfig.class,fallback UserServiceFallback.class // 熔断回退
)
public interface UserServiceClient { ... }熔断回退实现
Component
public class UserServiceFallback implements UserServiceClient {Overridepublic User getUserById(Long userId) {return new User(0L, 备用用户, fallbackexample.com);}
}日志配置 (application.yml)
logging:level:org.springframework.cloud.openfeign: DEBUG测试流程
启动 Eureka Server (8761端口)启动 User Service (8081端口)启动 Order Service (8080端口)访问测试http://localhost:8080/orders/123/user
关键概念总结
服务注册Provider 启动时向 Eureka 注册信息服务发现Consumer 通过服务名发现 Provider负载均衡Feign 自动实现多实例轮询声明式调用定义接口即完成远程调用熔断机制快速失败 服务降级 注当前 Spring Cloud 版本默认使用 LoadBalancer 替代 Ribbon最新版 OpenFeign 已内置负载均衡能力。 通过这个完整示例可以清晰看到Eureka实现服务治理、Feign简化服务调用的协作过程是构建微服务架构的基础设施。
