1. 搭建 Eureka 服务注册与调用 Hello World

1.1 创建 Eureka Server 模块

  1. <?xml version="1.0" encoding="UTF-8"?>
  3. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  5.   <modelVersion>4.0.0</modelVersion>
  7.   <groupId>com.example</groupId>
  8.   <artifactId>eureka-server</artifactId>
  9.   <version>0.0.1-SNAPSHOT</version>
  10.   <name>eureka-server</name>
  11.   <packaging>jar</packaging>
  13.   <parent>
  14.     <groupId>org.springframework.boot</groupId>
  15.     <artifactId>spring-boot-starter-parent</artifactId>
  16.     <version>1.5.13.RELEASE</version>
  17.   </parent>
  19.   <properties>
  20.     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  21.   </properties>
  23.   <dependencyManagement>
  24.     <dependencies>
  25.       <dependency>
  26.         <groupId>org.springframework.cloud</groupId>
  27.         <artifactId>spring-cloud-dependencies</artifactId>
  28.         <version>Edgware.SR3</version>
  29.         <type>pom</type>
  30.         <scope>import</scope>
  31.       </dependency>
  32.     </dependencies>
  33.   </dependencyManagement>
  35.   <dependencies>
  36.     <dependency>
  37.       <groupId>org.springframework.cloud</groupId>
  38.       <artifactId>spring-cloud-starter-eureka</artifactId>
  39.     </dependency>
  40.     <dependency>
  41.       <groupId>org.springframework.cloud</groupId>
  42.       <artifactId>spring-cloud-starter-eureka-server</artifactId>
  43.     </dependency>
  44.   </dependencies>
  45. </project>
server:
  port: 8761
spring:
  application:
    name: Eureka-Server
eureka:
  client:
    register-with-eureka: false
    fetch-registry: false
  • register-with-eureka：是否将该服务注册到 eureka 服务端，默认为 true，集群环境下使用；
  • fetch-registry：是否从 eureka 服务端获取其他服务实例，默认为 true，集群环境下使用； ```java @SpringBootApplication @EnableEurekaServer public class EurekaServer { public static void main(String[] args) {
      SpringApplication.run(EurekaServer.class, args);
    } }

- 启动后，访问 http://localhost:8761
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## 1.2 创建 Eureka Client 模块
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### 1.2.1 服务提供者 Service Producer
```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>org.example</groupId>
  <artifactId>service-producer</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>service-producer</name>

  <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>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.13.RELEASE</version>
  </parent>

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

  <dependencies>
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-eureka</artifactId>
    </dependency>
  </dependencies>
</project>

server:
  port: 8080
spring:
  application:
    name: Service-Producer
eureka:
  instance:
    hostname: localhost
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka

@RestController
public class ServiceProducerController {
    @GetMapping("/sayHello/{name}")
    public String sayHello(@PathVariable("name") String name){
        return "{'msg': 'hello, " + name + "'}";
    }
}

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

1.2.2 服务调用者 Service Consumer

<?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>org.example</groupId>
  <artifactId>service-consumer</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>service-consumer</name>

  <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>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.13.RELEASE</version>
  </parent>

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

  <dependencies>
    <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>
  </dependencies>


</project>

server:
  port: 9090
spring:
  application:
    name: Service-Consumer
eureka:
  instance:
    hostname: localhost
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka

@RestController
@Configuration
public class ServiceConsumerController {
    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }

    @GetMapping("greeting/{name}")
    public String greeting(@PathVariable("name") String name){
        RestTemplate restTemplate = getRestTemplate();
        return restTemplate.getForObject("http://Service-Producer/sayHello/" + name, String.class);
    }
}

  • RestTemplate，用于访问单个 http 接口的，加了 @LoadBalanced 以后就可以通过 Ribbon 的支持，实现负载均衡，加入 Service-Producer 部署了几台机器，那么可以自动负载均衡，轮询调用每一个实例。

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

  • 启动后，访问 http://localhost:9090/greeting/shawn，结果可以看到调用了 Service Producer 的 API；

    2. 搭建 Eureka 集群及应用集群的注册发现

    2.1 创建两个 Eureka 实例

    2.1.1 eureka-server-01

    server:
port: 8761
spring:
application:
  name: eureka-server-01
eureka:
client:
  register-with-eureka: true
  fetch-registry: true
  serviceUrl:
    defaultZone: http://localhost:8762/eureka/
instance:
  hostname: localhost

    2.1.2 eureka-server-02

    server:
port: 8762
spring:
application:
  name: eureka-server-02
eureka:
client:
  register-with-eureka: true
  fetch-registry: true
  serviceUrl:
    defaultZone: http://localhost:8761/eureka/
instance:
  hostname: localhost

    同一个工程同时运行两个 eureka server 实例。

    2.2 创建两个 Service Producer 实例

    server:
port: 8080
spring:
application:
  name: Service-Producer
eureka:
instance:
  hostname: localhost
client:
  service-url:
    defaultZone: http://localhost:8761/eureka,http://localhost:8762/eureka

    server:
port: 8088
spring:
application:
  name: Service-Producer
eureka:
instance:
  hostname: localhost
client:
  service-url:
    defaultZone: http://localhost:8761/eureka,http://localhost:8762/eureka

    同一个工程同时运行两个 service producer 实例。

    2.3 创建一个 Service Consumer 实例

    server:
port: 9090
spring:
application:
  name: Service-Consumer
eureka:
instance:
  hostname: localhost
client:
  service-url:
    defaultZone: http://localhost:8761/eureka,http://localhost:8762/eureka

    运行结果：
    image.png