微服务架构-SpringCloud

微服务架构是一种架构模式，它提倡将单一应用程序划分成一组小的服务，这些服务都运行在自己的进程中，服务之间通过轻量级的通信机制互相协作。

Spring Cloud是一个提供工具支持以快速、便捷的方式实现微服务架构中一些常见模式的Spring子项目。

以下是一个简单的Spring Cloud示例，使用Spring Cloud Netflix的Eureka作为服务注册中心，以及Spring Cloud OpenFeign作为服务间调用的方式。

1. 创建Eureka Server:

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

application.properties:

spring.application.name=eureka-server
server.port=8761
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

2. 创建Service Provider:

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

application.properties:

spring.application.name=service-provider
server.port=8080
eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

Service:

@RestController
public class ServiceController {
    @GetMapping("/hello")
    public String hello() {
        return "Hello from Service Provider";
    }
}

3. 创建Service Consumer:

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

application.properties:

spring.application.name=service-consumer
server.port=8081
eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

Feign Client:

@FeignClient("service-provider")
public interface ServiceProviderClient {
    @GetMapping("/hello")
    String hello();
}

Controller:

@RestController
public class ConsumerController {
    @Autowired
    private ServiceProviderClient serviceProviderClient;
 
    @GetMapping("/call-service")
    public String callService() {
        return serviceProviderClient.hello();