微服务框架——SpringCloud（二）

1.Feign声明式服务调用（负载均衡+熔断器）

　　a.概念：Feign是一个声明式的Web Service客户端，它的目的就是让Web Service调用更加简单。Feign整合了Ribbon和Hystrix。

　　b.新建springboot项目，依赖选择 Eureka Discovery 、Web 以及 Feign

　　c.pom文件关键依赖

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>2.1.3.RELEASE</version>

        <relativePath/> <!-- lookup parent from repository -->

    </parent>

    <dependencies>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-openfeign</artifactId>

        </dependency>

        ......

    </dependencies>

    ......

　　d.application.yml文件

spring:

  application:

    name: eureka-client-feign

server:

  port: 8086

eureka:

  client:

    service-url:

      defaultZone: http://localhost:8081/eureka/

　　c.启动类添加注解 @EnableDiscoveryClient 和 @EnableFeignClients

@SpringBootApplication

@EnableDiscoveryClient

@EnableFeignClients

public class EurekaClientFeignApplication {

    public static void main(String[] args) {

        SpringApplication.run(EurekaClientFeignApplication.class, args);

    }

}

　　d.创建接口调用服务

@FeignClient(value = "EUREKA-CLIENT-PRODUCER",fallback = FeignFallBack.class)

public interface FeignService {

    @RequestMapping(value = "/printProducer")

    public String printProducer(@RequestParam("param") String param);

}

　　c.创建熔断器实现接口

@Component

public class FeignFallBack implements FeignService {

    @Override

    public String printProducer(String param) {

        return "连接消费服务失败，请求参数：" + param;

    }

}

　　d.具体使用

@RestController

public class CommonController {

    @Resource

    FeignService feignService;

    @RequestMapping(value = "/print")

    public String print(String param){

        return feignService.printProducer(param);

    }

}

巴特西

微服务框架——SpringCloud（二）

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