引入依赖
<!-- pom.xml --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> // 启动类开启 Feign @SpringBootApplication @EnableFeignClients public class OrderApplication { public static void main(String[] args) { SpringApplication.run(OrderApplication.class, args); } }回到顶部
二、声明 Feign 客户端
// 调用 user-service 的 Feign 接口 @FeignClient(name = "user-service", path = "/api/users") public interface UserFeignClient { @GetMapping("/{id}") User getUserById(@PathVariable("id") Long id); @PostMapping User createUser(@RequestBody User user); @GetMapping List<User> listUsers(@RequestParam("page") int page, @RequestParam("size") int size); @DeleteMapping("/{id}") void deleteUser(@PathVariable("id") Long id); } // 在 Service 中注入使用 @Service public class OrderService { @Autowired private UserFeignClient userFeignClient; public Order createOrder(Long userId, Long productId) { // 像调用本地方法一样调用远程服务 User user = userFeignClient.getUserById(userId); // 业务逻辑... } }回到顶部
三、配置超时和重试
# application.yml feign: client: config: default: connectTimeout: 5000 readTimeout: 10000 loggerLevel: FULL user-service: connectTimeout: 3000 readTimeout: 5000 # 全局超时配置 ribbon: ConnectTimeout: 3000 ReadTimeout: 5000 MaxAutoRetries: 1 MaxAutoRetriesNextServer: 2回到顶部
四、Feign 日志配置
@Configuration public class FeignConfig { @Bean public Logger.Level feignLoggerLevel() { return Logger.Level.FULL; // 记录完整请求响应 } } // 在 FeignClient 中使用自定义配置 @FeignClient(name = "user-service", configuration = FeignConfig.class) public interface UserFeignClient { // ... } # 日志级别说明 # NONE: 无日志（默认） # BASIC: 仅记录请求方法、URL、响应状态码、执行时间 # HEADERS: 记录 BASIC + 请求/响应头 # FULL: 记录 HEADERS + 请求/响应体回到顶部
五、请求拦截器（传递 Token）
@Component public class FeignAuthInterceptor implements RequestInterceptor { @Override public void apply(RequestTemplate template) { // 从请求上下文获取 Token ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes(); if (attributes != null) { HttpServletRequest request = attributes.getRequest(); String token = request.getHeader("Authorization"); if (token != null) { // 将 Token 传递给下游服务 template.header("Authorization", token); } } } } // 配置拦截器 @Configuration public class FeignConfig { @Bean public RequestInterceptor feignAuthInterceptor() { return new FeignAuthInterceptor(); } }回到顶部
六、Fallback 降级
@FeignClient(name = "user-service", fallbackFactory = UserFeignFallbackFactory.class) public interface UserFeignClient { @GetMapping("/{id}") User getUserById(@PathVariable("id") Long id); } // 降级工厂：可以获取到异常信息 @Component public class UserFeignFallbackFactory implements FallbackFactory<UserFeignClient> { @Override public UserFeignClient create(Throwable cause) { return new UserFeignClient() { @Override public User getUserById(Long id) { log.error("调用 user-service 失败", cause); return new User(id, "默认用户", "降级数据"); } }; } } # 开启降级 feign.circuitbreaker.enabled: true