1. 程式人生 > >SpringCloud之服務提供與呼叫(Ribbon,Feign)

SpringCloud之服務提供與呼叫(Ribbon,Feign)

本系列介紹的配置均基於 Spring Boot 2.0.1.RELEASE 版本和 Spring Cloud Finchley.SR1

eureka註冊續約流程

  1. 啟動註冊中心
  2. 服務提供者生產服務並註冊到服務中心中
  3. 消費者從服務中心中獲取服務並執行

image


    </properties>

    <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>
    </dependencies>

    <build>
        <finalName>producer-service</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2.建立啟動類

Finchley版本已經不需要新增@EnableDiscoveryClient註解,Spring Cloud會自動識別。

@SpringBootApplication
public class ProducerServiceApplication {

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

}

3.配置檔案

spring.application.name=producer-service
server.port=9001
#eureka
eureka.client.serviceUrl.defaultZone=http://localhost:8001/eureka/
  • spring.application.name 服務提供者的名字
  • server.por 服務埠號
  • eureka.client.serviceUrl.defaultZone eureka的服務註冊地址,如果eureka是多節點,多個地址逗號分隔,具體可以看上一篇部落格:服務註冊與發現。

多節點eureka服務註冊如下:

eureka.client.serviceUrl.defaultZone=http://localhost:8001/eureka/,http://localhost:8002/eureka/

4.Action or Controller類

@RestController
@RequestMapping(value = "/test")
public class ProducerAction {

    @RequestMapping(value = "", method = RequestMethod.GET)
    public String test(String param) {
        return "param is " + param;
    }

}

5.啟動服務

6.呼叫下試試

param is test

服務消費 ribbon

Ribbon 了,它是一個基於 HTTP 和 TCP 的客戶端負載均衡器。它可以通過在客戶端中配置ribbonServerList 來設定服務端列表去輪詢訪問以達到均衡負載的作用。

當 Ribbon 與 Eureka聯合使用時,ribbonServerList會被DiscoveryEnabledNIWSServerList 重寫,擴充套件成從 Eureka 註冊中心中獲取服務例項列表。同時它也會用 NIWSDiscoveryPing 來取代 IPing,它將職責委託給 Eureka 來確定服務端是否已經啟動。

1.在spring-cloud-manage下建立一個子專案consumer-service

pom.xml檔案如下

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-cloud-manage</artifactId>
        <groupId>org.springcloudmanage</groupId>
        <version>1.0</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>consumer-service</artifactId>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <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>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

spring-cloud-starter-netflix-eureka-client中已經引用了ribbon先關的jar,所需不需要再引入了

2.建立啟動類

@SpringBootApplication
public class ConsumerServiceApplication {

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

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

}

3.配置檔案

spring.application.name=consumer-service
server.port=9002
#eureka
eureka.client.serviceUrl.defaultZone=http://localhost:8001/eureka/

4.Action or Controller類

這裡注入restTemplate,Spring Cloud Ribbon 自己有攔截器會對 服務名producer-service做解析,自動的去選取服務例項負載均衡呼叫,並將服務名替換成實際要請求的IP地址和埠

@RestController
@RequestMapping(value = "/ribbon/test")
public class ConsumerAction {

    @Autowired
    private RestTemplate restTemplate;

    @RequestMapping(value = "", method = RequestMethod.GET)
    public String test(String param) {
        String url = "http://producer-service/test/?param=" + param;
        return restTemplate.getForObject(url, String.class);
    }
    
}

5.啟動服務

消費端服務啟動成功後,可以看到erueka時已經顯示註冊成功了

image

5.呼叫消費端服務

param is ribbon-test

控制檯日誌

2018-08-28 16:25:23.397  INFO 3791 --- [nio-9002-exec-1] c.netflix.config.ChainedDynamicProperty  : Flipping property: producer-service.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2018-08-28 16:25:23.414  INFO 3791 --- [nio-9002-exec-1] c.n.u.concurrent.ShutdownEnabledTimer    : Shutdown hook installed for: NFLoadBalancer-PingTimer-producer-service
2018-08-28 16:25:23.433  INFO 3791 --- [nio-9002-exec-1] c.netflix.loadbalancer.BaseLoadBalancer  : Client: producer-service instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=producer-service,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2018-08-28 16:25:23.440  INFO 3791 --- [nio-9002-exec-1] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
2018-08-28 16:25:23.462  INFO 3791 --- [nio-9002-exec-1] c.netflix.config.ChainedDynamicProperty  : Flipping property: producer-service.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2018-08-28 16:25:23.463  INFO 3791 --- [nio-9002-exec-1] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client producer-service initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=producer-service,current list of Servers=[192.168.101.238:9001],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone;	Instance count:1;	Active connections count: 0;	Circuit breaker tripped count: 0;	Active connections per server: 0.0;]
},Server stats: [[Server:192.168.101.238:9001;	Zone:defaultZone;	Total Requests:0;	Successive connection failure:0;	Total blackout seconds:0;	Last connection made:Thu Jan 01 08:00:00 CST 1970;	First connection made: Thu Jan 01 08:00:00 CST 1970;	Active Connections:0;	total failure count in last (1000) msecs:0;	average resp time:0.0;	90 percentile resp time:0.0;	95 percentile resp time:0.0;	min resp time:0.0;	max resp time:0.0;	stddev resp time:0.0]
]}ServerList:org.springf[email protected]12e48993
2018-08-28 16:25:24.447  INFO 3791 --- [erListUpdater-0] c.netflix.config.ChainedDynamicProperty  : Flipping property: producer-service.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647

可以啟動多個producer-service服務測試下實際的負載均衡效果。

服務消費 feign

Feign是一個宣告式的Web Service客戶端,它使得編寫Web Serivce客戶端變得更加簡單。我們只需要使用Feign來建立一個介面並用註解來配置它既可完成。它具備可插拔的註解支援,包括Feign註解和JAX-RS註解。Feign也支援可插拔的編碼和解碼。Spring Cloud為Feign增加了對Spring MVC註解的支援,還整合了Ribbon和Eureka來提供均衡負載的HTTP客戶端實現。

在實際工作中,我們基本上都是使用Feign來完成呼叫的。我們通過一個例子來展現 Feign 如何方便的宣告對 eureka-producer 服務的定義和呼叫。

1.consumer-service新增對feign的依賴

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-cloud-manage</artifactId>
        <groupId>org.springcloudmanage</groupId>
        <version>1.0</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>consumer-service</artifactId>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

2.啟動類上加上feign所需註解

@EnableFeignClients
@SpringBootApplication
public class ConsumerServiceApplication {

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

}

3.配置檔案

spring.application.name=consumer-service
server.port=9002
#eureka
eureka.client.serviceUrl.defaultZone=http://localhost:8001/eureka/
#開啟Hystrix斷路器
feign.hystrix.enabled=true
#斷路器的超時時間需要大於ribbon的超時時間,不然不會觸發重試,預設為1000
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=5000

4.feign 呼叫

建立feign客戶端呼叫類,其中name為所需呼叫的服務名,fallback使用Hystrix,當producer-service不可用時,對服務做降級,並返回友好提示

@FeignClient(name = "producer-service", fallback = ProducerServiceFeignClientHystrix.class)
public interface ProducerServiceFeignClient {

    @RequestMapping(value = "/test", method = RequestMethod.GET)
    String test(@RequestParam("param") String param);

}

==注意@RequestParam("param")中name必須要和producer-service服務中的引數名一致==

@Component
public class ProducerServiceFeignClientHystrix implements ProducerServiceFeignClient {
    @Override
    public String test(String param) {
        return "服務[producer-service]無法訪問";
    }
}
param is feign-test

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服務[producer-service]無法訪問