java - 服务发现中的 eureka unknownHostException

Question

我有两个微服务，

1. 运行在 localhost:8081 上的 eureka-client-1
2. 运行在 localhost:8082 上的 eureka-client-2

这两个都是在 localhost:8761 上运行的“eureka-server”注册的 DiscoveryClients。

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

经过搜索，我发现我需要使用“Brixton”来完成它。

有没有办法用 Camden.SR3 做到这一点？

请提出建议。

@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";
    }
}

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，客户端 2 类似(只是更改名称，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，解决这个问题唯一需要做的就是添加 spring 注释@LoadBalanced

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