Spring Cloud Feign

建立spring-cloud-04-feign-service服務中心 埠為8088

建立spring-cloud-04-feign-produce 埠為2006

• HystrixC類

@RestController
public class HystrixC {

    @RequestMapping(value = "/hello",method = {RequestMethod.GET})
    public String hello() throws InterruptedException {
        System.err.println("hello hystrix ...."
 
);
        return "hello hystrix ...";
    }

    @RequestMapping(value = "/action",method = {RequestMethod.GET})
    public String action() throws InterruptedException {
        Thread.sleep(4000);
        System.err.println("action hystrix ....");
        return "action hystrix ...";
    }
}

• Application類

@EnableDiscoveryClient
@SpringBootApplication
public class FeignProduceApplication {

    @Bean
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

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

建立spring-cloud-04-feign-consumer

• pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-feign</artifactId>
</dependency>

• application.properties也可以對feign代理做一些高效能輸入輸出配置
• 注意：feign在第四個版本後需要手動開啟斷路器功能才能生效

pring.application.name=feign-consumer
server.context-path=/
server.port=2005
eureka.client.service-url.defaultZone=http://eureka1:8008/eureka/
#啟動重試機制
spring.cloud.loadbalancer.retry.enabled=true 
##斷路器
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=50000


eq.fact.connect-timeout=1000
eq.fact.connection-request-timeout=1000
eq.fact.read-timeout=5000

#是否對所有請求都進行重試
lient-service.ribbon.OKToRetryOnAllOperations=true
#重試切換例項得次數
lient-service.ribbon.MaxAutoRetriesNextServer=1
#重試切次數
lient-service.ribbon.MaxAutoRetries=2

feign.hystrix.enabled=true
#壓縮 超過設定得大小得請求才會對其進行壓縮 這是預設值
feign.compression.request.min-request-size=2048
feign.compression.request.mime-types=text/xml,application.xml,application/json
feign.compression.request.enabled=true
feign.compression.response.enabled=true

• Application類

@EnableFeignClients
@EnableCircuitBreaker //開啟斷路器
@EnableDiscoveryClient
@SpringBootApplication
public class FeignConsumerApplication {

    @Bean
    @ConfigurationProperties(prefix = "req.fact")
    public HttpComponentsClientHttpRequestFactory httpComponentsClientHttpRequestFactory() {
        return new HttpComponentsClientHttpRequestFactory();
    }

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate() {
        return new RestTemplate(httpComponentsClientHttpRequestFactory());
    }

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

• HelloService介面 這個interface一定是已知服務（也就是註冊到Eureka上得介面服務）FeignClient註解就是Fegin得註解宣告，裡面name屬性表示了當前代理得服務AppName，fallback屬性是呼叫服務失敗後得降級策略，當網路異常等呼叫代理失敗後，會根據斷路器得超時時間降級到指定得fallback賦予得HelloServiceHystrixFallback類中，做降級處理。

@FeignClient(name = "feign-produce", fallback = HelloServiceHystrixFallback.class)
public interface HelloService {

    @RequestMapping(value = "/hello", method = {RequestMethod.GET})
    String hello();

    @RequestMapping(value = "/action", method = {RequestMethod.GET})
    String action();
}

• ConsumerController類

@RestController
public class ConsumerController {

    @Autowired
    HelloService helloService;

    @RequestMapping(value = "/hello", method = {RequestMethod.GET})
    public String helloConsumer() {
        return helloService.hello()+"\n";
    }

    @RequestMapping(value = "/action", method = {RequestMethod.GET})
    public String helloAction() {
        return helloService.action();
    }
}

• 啟動所有訪問http://localhost:2005/action就可以訪問到

fegin日誌配置

• 在application.properties中配置

# feign日誌配置
logging.level.com.springcloud.feign.HelloService=DEBUG

• 在Aplication啟動類中新增

 @Bean
    Logger.Level feignLoggerLevel() {
        /**
         *  NONE: 不記錄任何資訊
         *  BASIE:僅記錄請求方法，URL以及響應狀態碼和執行時間
         *  HEADERS:除了記錄BASIE級別得資訊之外，還會記錄請求和響應得頭資訊
         *  FULL：記錄所有請求與響應得明細，包括頭資訊，請求體，元資料等。
         */
        return Logger.Level.FULL;
    }

• GitHub地址

• 下節API閘道器治理元件Zuul