Question

我有两个微服务，

eureka-client-1在localhost上运行：8081
eureka-client-2在localhost上运行：8082

这些都是在＆eureka-server＆＃39;注册的DiscoveryClients。在localhost上运行：8761。

在下面的代码段中，我尝试从eureka-client-1调用eureka-client-2。我想调用http://localhost:8082而不是调用http://eureka-client-2，但这会在Eureka服务发现期间抛出java.net.UnknownHostException。

搜索后，我发现我需要使用＆＃34; Brixton＆＃34;完成它。

有没有办法用Camden.SR3做到这一点？

请建议。

@Component
public class HystrixDemoService {   

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

    @HystrixCommand(fallbackMethod = "getFallbackCustomerName")
    public String getCustomerName() {
        RestTemplate restTemplate = new RestTemplate();
        URI uri = URI.create("http://eureka-client-2");     // fails here
        return restTemplate.getForObject(uri, String.class);
    }

    public String getFallbackCustomerName() {
        System.out.println("coming inside fallback method");
        return "Resillient Customer";
    }
}

的pom.xml

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>demo-pranay-eureka-client1</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo-pranay-eureka-client1</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</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-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Camden.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

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


</project>

客户端1的application.properties，类似于客户端2（只需更改名称，即eureka-client-2）

spring.application.name=eureka-client-1
server.port=8081
eureka:
  client:
    registerWithEureka: true
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
  instance:
    leaseRenewalIntervalInSeconds: 10
    statusPageUrlPath: /info
    healthCheckUrlPath: /health

eureka服务器的application.properties

spring.application.name=eureka-service
server.port=8761
eureka:
  client:
    registerWithEureka: false
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
  instance:
    leaseRenewalIntervalInSeconds: 10
    statusPageUrlPath: /info
    healthCheckUrlPath: /health

Answer 1

对我来说，解决问题唯一需要做的就是将弹簧注释@LoadBalanced添加到

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

Answer 2

解决方案是您错过了@LoadBalanced。
如果您使用Spring Boot或Sprint Cloud，则我更喜欢使用RestTemplateBuilder builder

  @Bean
  @LoadBalanced
  public RestTemplate restTemplate(RestTemplateBuilder builder) {
    return builder.build();
  }

如果仅使用spring，建议您new RestTemplate()

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

Answer 3

如前所述，我相信您可能会错过Ribbon中的eureka-client-1配置。

首先，我会动：

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

到配置类。

将Ribbon配置添加到application.yml，例如：

the-eureka-client-2:
   ribbon:
     # Eureka vipAddress of the target service
     DeploymentContextBasedVipAddresses: eureka-client-2

     #listOfServers: localhost:${SERVER.PORT}
     NIWSServerListClassName: com.netflix.niws.loadbalancer.DiscoveryEnabledNIWSServerList

     # Interval to refresh the server list from the source (ms)
     ServerListRefreshInterval: 30000

在restTemplate类中注入HystrixDemoService，而不是为每个请求实例化一个新的@Component public class HystrixDemoService { @Autowired public RestTemplate restTemplate; ... @HystrixCommand(fallbackMethod = "getFallbackCustomerName") public String getCustomerName() { URI uri = URI.create("http://eureka-client-2"); return this.restTemplate.getForObject(uri, String.class); }。 RestTemplate是线程安全的：

the-eureka-client-2

其中eureka-client-2是映射到名称为Jersey 1的注册服务的密钥

我在博客上发表了Microservices Registration and Discovery using Spring Cloud Eureka, Ribbon and Feign，其中还包括Discovery服务器的源代码以及使用Spring MVC和server { access_log /var/log/nginx/artifactory_access.log timed_combined; error_log /var/log/nginx/artifactory_error.log; listen 80; server_name artifactory.inmz.net; location / { proxy_pass http://utils-1:8080; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header Host $host; #proxy_set_header X-Forwarded-Proto https; proxy_set_header X-Real-IP $remote_addr; proxy_http_version 1.1; proxy_set_header Connection ""; } }开发的两个客户端。

Answer 4

以下更改对我有用。

@SpringBootApplication
public class DemoPranayEurekaClient1Application {
    public static void main(String[] args) {
        SpringApplication.run(DemoPranayEurekaClient1Application.class, args);
    }
}

@EnableDiscoveryClient
@EnableCircuitBreaker
@RestController
class HystrixDemoApplication {
    @Autowired
    HystrixDemoService hystrixDemoService;

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

    @RequestMapping("/")
    public String name() {
        String str = hystrixDemoService.getCustomerName();
        return "I'm A talking to "+str;
    }

}

以下是用于选择eureka-client-2 ...

实例的代码行

ServiceInstance instance = loadBalancer.choose（＆＃34; eureka-client-2＆＃34;）;

@Component
public class HystrixDemoService {

    @Autowired
    private LoadBalancerClient loadBalancer;

    @HystrixCommand(fallbackMethod = "getFallbackCustomerName")
    public String getCustomerName() {
        RestTemplate restTemplate = new RestTemplate();
        ServiceInstance instance = loadBalancer.choose("eureka-client-2");
        URI uri = instance.getUri();
        return restTemplate.getForObject(uri, String.class);
    }

    public String getFallbackCustomerName() {
        System.out.println("coming inside fallback method");
        return "Resillient Customer";
    }
}

服务发现

4 个答案: