在Feign中使用Hystrix实现服务调用容错

1、在Feign中用Hystrix实现服务调用容错

1.1、添加依赖和配置，并启用支持

1.1.1、添加依赖

        <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>

1.1.2、添加配置

spring.application.name=hystrix
server.port=50007
eureka.client.fetch-registry=true
eureka.client.register-with-eureka=false
eureka.client.service-url.defaultZone=http://eureka01:50001/eureka/,http://eureka02:50002//eureka/
#开启支持
feign.hystrix.enabled=true

1.1.3、添加对Feign的支持

@EnableFeignClients //开启Feign支持
@SpringBootApplication
public class HystrixSpringcloudApplication {

    public static void main(String[] args) {
        SpringApplication.run(HystrixSpringcloudApplication.class, args);
    }
}

1.2、添加Feign接口

@FeignClient(name = "provider")
public interface FeignClients {

    @GetMapping("/hello")
    public String hello();
}

1.3、添加Controller

@RestController
public class HelloController {

    @Autowired
    FeignClients feignClients;

    @GetMapping("/hello")
    public String index(){
        return feignClients.hello();
    }
}

1.4、实现回调类

@Component
public class HelloHstrix implements FeignClients {
    @Override
    public String hello() {
        return "出现错误！";
    }
}

1.5、添加fallback属性

@FeignClient(name = "provider",fallback = HelloHstrix.class)
public interface FeignClients {

    @GetMapping("/hello")
    public String hello();
}

1.6、测试fallbakc状态

只开启"服务中心"，访问http://localhost:50007/hello，会提示错误。当把"服务提供者"也开启则会返回正确的数据。