SpringCloud Ribbon 示例

目標(biāo)

基于 eureka惹谐，創(chuàng)建一個后端service碾篡，使用不同端口運行3個實例舰绘，創(chuàng)建一個client service蹂喻，通過 ribbon 調(diào)用后端service，驗證負(fù)載均衡效果捂寿。

創(chuàng)建 eureka server

artifactId：eureka-server口四，spring boot: 1.5.16，依賴：

<dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.6</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.6</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.6</version>
        </dependency>
    </dependencies>

啟動類添加注解 @EnableEurekaServer秦陋，配置文件：

spring.application.name=eurekaserver
server.port=8082
 
eureka.instance.hostname=localhost
 
eureka.client.serviceUrl.defaultZone=http://localhost:8082/eureka/
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false

啟動蔓彩，查看頁面 http://localhost:8082，看是否正常顯示驳概。

創(chuàng)建后端服務(wù)

artifactId：backend-service赤嚼，依賴：

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <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>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.6</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.6</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.6</version>
        </dependency>

啟動類添加 @EnableEurekaClient，配置文件：

spring.application.name=server
server.port = 9090
 
eureka.client.serviceUrl.defaultZone= http://localhost:8082/eureka/
eureka.client.healthcheck.enabled= true
eureka.instance.leaseRenewalIntervalInSeconds= 1
eureka.instance.leaseExpirationDurationInSeconds= 2

測試接口：

@RestController
public class MyRestController {
 
    @Autowired
    Environment environment;
 
    @GetMapping("/")
    public String health() {
        return "I am Ok";
    }
 
    @GetMapping("/backend")
    public String backend() {
        System.out.println("Inside MyRestController::backend...");
 
        String serverPort = environment.getProperty("local.server.port");
 
        System.out.println("Port : " + serverPort);
 
        return "Hello form Backend!!! " + " Host : localhost " + " :: Port : " + serverPort;
    }
}

啟動顺又，訪問接口探膊，看是否正常。

創(chuàng)建 ribbon client 服務(wù)

artifactId：ribbon-client待榔，依賴：

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <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>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.6</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.6</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>2.9.6</version>
        </dependency>
    </dependencies>

配置文件：

spring.application.name=client
server.port=8888
 
eureka.client.serviceUrl.defaultZone= http://localhost:8082/eureka/
eureka.client.healthcheck.enabled= true
eureka.instance.leaseRenewalIntervalInSeconds= 1
eureka.instance.leaseExpirationDurationInSeconds= 2
 
server.ribbon.eureka.enabled=true
server.ribbon.ServerListRefreshInterval=1000

ribbon 配置類：

public class RibbonConfiguration {
 
    @Autowired
    IClientConfig config;
    
    @Bean
    public IPing ribbonPing(IClientConfig config) {
        return new PingUrl();
    }
 
    @Bean
    public IRule ribbonRule(IClientConfig config) {
        return new AvailabilityFilteringRule();
    }
}

啟動類：

@SpringBootApplication
@EnableDiscoveryClient
@RibbonClient(name = "server", configuration = RibbonConfiguration.class)
public class RibbonClientApplication {

    @Bean
    @LoadBalanced
    public RestTemplate proviceRestTemplate() {
        return new RestTemplate();
    }
    
    public static void main(String[] args) {
        SpringApplication.run(RibbonClientApplication.class, args);
    }
}

測試類：

@RestController
public class HelloController {
    @Autowired
    private RestTemplate restTemplate;
    
    @GetMapping("/hi")
    public String hi() {
        return restTemplate.getForObject("http://server/backend", String.class);
    }
}

運行測試

啟動 eureka server逞壁，然后啟動3個后端服務(wù)：

java -jar -Dserver.port=9090 target/backend-service-0.0.1-SNAPSHOT.jar
java -jar -Dserver.port=9091 target/backend-service-0.0.1-SNAPSHOT.jar
java -jar -Dserver.port=9092 target/backend-service-0.0.1-SNAPSHOT.jar

啟動 ribbon client，訪問測試接口：

http://localhost:8888/hi

多次刷新锐锣，就可以看到顯示不同的端口號腌闯，說明負(fù)載均衡生效。