【网关、RPC和Feign的成套示例代码】

网关、RPC和Feign的成套示例代码

分别给出基于Spring Boot/Cloud的网关、RPC(使用Dubbo)和Feign的完整示例代码。

1. Spring Cloud Gateway 网关示例

网关服务 (gateway-service)

application.yml

server:
  port: 8080

spring:
  cloud:
    gateway:
      routes:
        - id: user-service
          uri: lb://user-service
          predicates:
            - Path=/api/users/**
          filters:
            - StripPrefix=1
        - id: order-service
          uri: lb://order-service
          predicates:
            - Path=/api/orders/**
          filters:
            - StripPrefix=1

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka

GatewayApplication.java

@SpringBootApplication
@EnableDiscoveryClient
public class GatewayApplication {
    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class, args);
    }
}

2. Dubbo RPC 示例

服务提供者 (user-service-provider)

pom.xml 添加依赖

<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo-spring-boot-starter</artifactId>
    <version>2.7.15</version>
</dependency>
<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo-registry-nacos</artifactId>
    <version>2.7.15</version>
</dependency>

application.yml

dubbo:
  application:
    name: user-service-provider
  registry:
    address: nacos://localhost:8848
  protocol:
    name: dubbo
    port: 20880

服务接口定义

public interface UserService {
    User getUserById(Long id);
}

@Data
public class User implements Serializable {
    private Long id;
    private String name;
    private String email;
}

服务实现

@Service
public class UserServiceImpl implements UserService {
    @Override
    public User getUserById(Long id) {
        // 模拟数据库查询
        User user = new User();
        user.setId(id);
        user.setName("User" + id);
        user.setEmail("user" + id + "@example.com");
        return user;
    }
}

服务消费者 (order-service-consumer)

调用服务

@RestController
@RequestMapping("/orders")
public class OrderController {
    
    @Reference
    private UserService userService;
    
    @GetMapping("/{id}/user")
    public User getUserByOrderId(@PathVariable Long id) {
        // 通过RPC调用用户服务
        return userService.getUserById(id);
    }
}

3. Feign 客户端示例

服务提供者 (user-service)

UserController.java

@RestController
@RequestMapping("/users")
public class UserController {
    
    @GetMapping("/{id}")
    public User getUserById(@PathVariable Long id) {
        User user = new User();
        user.setId(id);
        user.setName("User" + id);
        user.setEmail("user" + id + "@example.com");
        return user;
    }
}

服务消费者 (order-service)

pom.xml 添加依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

application.yml

feign:
  client:
    config:
      default:
        connectTimeout: 5000
        readTimeout: 5000
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka

Feign客户端接口

@FeignClient(name = "user-service")
public interface UserServiceClient {
    
    @GetMapping("/users/{id}")
    User getUserById(@PathVariable Long id);
}

使用Feign客户端

@RestController
@RequestMapping("/orders")
public class OrderController {
    
    @Autowired
    private UserServiceClient userServiceClient;
    
    @GetMapping("/{id}/user")
    public User getUserByOrderId(@PathVariable Long id) {
        // 通过Feign调用用户服务
        return userServiceClient.getUserById(id);
    }
}

启动类添加注解

@SpringBootApplication
@EnableFeignClients
@EnableDiscoveryClient
public class OrderServiceApplication {
    public static void main(String[] args) {
        SpringApplication.run(OrderServiceApplication.class, args);
    }
}

总结对比

1. 网关：

   • 适合作为系统统一入口
   • 配置路由规则即可，无需编码
   • 示例展示了基于路径的路由配置

2. Dubbo RPC：

   • 需要定义服务接口并添加@Reference引用
   • 性能高，适合内部高性能调用
   • 需要单独的注册中心(Nacos)

3. Feign：

   • 声明式REST客户端
   • 与Spring Cloud生态集成好
   • 基于HTTP，适合RESTful风格服务

内部服务调用通常推荐使用Feign或Dubbo而不是通过网关中转。