feign-demo

本模块主要演示集成了Feign、Hystrix的Eureka客户端。

FeignClient方式调用接口

url	desc
http://localhost:8181/hello	输出hello信息 [eureka-client]
http://localhost:8181/user-feign/1	根据ID获取User [db-rest]
http://localhost:8181/user-feign/getUserByName/张三	根据name获取User [db-rest]
http://localhost:8181/user-feign/getUserByAddress/test	根据地址获取User [db-rest]

RestTemplate方式调用接口

url	desc
http://localhost:8181/user-rest/1	根据ID获取User [db-rest]

Hystrix Dashboard监控

url	desc
http://localhost:8181/hystrix	查看仪表盘
http://localhost:8181/hystrix.stream	在仪表盘中增加监控

配置FeignClient

引入Maven依赖


    org.springframework.cloud
    spring-cloud-starter-feign

启用FeignClient

spring boot启动类增加@EnableFeignClients注解，使其自动扫描@FeignClient

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

定义需要通过FeignClient访问的接口列表，如下：

// value为服务名，对应spring.application.name。注意：此服务名必须已注册进Eureka服务中心
@FeignClient(value = "db-rest", fallback = UserServiceFeignClientFallback.class)
public interface UserServiceFeignClient extends UserService {

}

// 定义FeignClient接口访问列表。注意：地址一定要正确
public interface UserService {
    @RequestMapping(value = "/api/user/{id}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE)
    User getUser(@PathVariable("id") int id);

    @RequestMapping(value = "/api/user/search/findByName?name={name}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE)
    User findUserByName(@PathVariable("name") String name);

    @RequestMapping(value = "/api/user/search/findByAddress?address={address}", method = RequestMethod.GET)
    String findUserByAddress(@PathVariable("address") String address);
}

// 定义各接口对应的fallback方法
@Component
public class UserServiceFeignClientFallback implements UserServiceFeignClient {

    @Override
    public User getUser(int id) {
        return new User("getUser.Fallback", "feignClient return");
    }

    @Override
    public User findUserByName(String name) {
        return new User("findUserByName.Fallback", "feignClient return");
    }

    @Override
    public String findUserByAddress(String address) {
        return "fallback";
    }
}

以下是RestTemplate调用方式：

public User getUser(int id) {
    User user = restTemplate.exchange( "http://db-rest/api/user/{id}", HttpMethod.GET, null, new ParameterizedTypeReference<User>() { }, id).getBody();
    return user; 
}

配置Hystrix

引入Maven依赖


    org.springframework.cloud
    spring-cloud-starter-hystrix

增加Hystrix配置

以下仅配置了启用超时及超时时间

@HystrixCommand(commandProperties = {
        @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "1000"),
        @HystrixProperty(name = "execution.timeout.enabled", value = "false") })
@RequestMapping(value = "/user-feign/{id}", method = RequestMethod.GET)
public User getUser(@PathVariable int id) {
    return userServiceFeignClient.getUser(id);
}

配置Hystrix Dashboard

引入Maven依赖


    org.springframework.boot
    spring-boot-starter-actuator



    org.springframework.cloud
    spring-cloud-starter-hystrix-dashboard

*　启用Hystrix Dashboard

spring boot启动类增加@EnableHystrixDashboard和@EnableCircuitBreaker注解，启用Hystrix Dashboard

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