Eureka服务注册与发现

發表於 | 分類於 | | 閱讀次數:

Eureka是Netflix开发的服务发现框架，本身是一个基于REST的服务，主要用于定位运行在AWS域中的中间层服务，以达到负载均衡和中间层服务故障转移的目的。Spring Cloud将它集成在其他子项目spring-cloud-netflix中，以实现spring cloud服务发现功能。

注册中心

注册中心地址

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http://admin:pwd123@node1.test.com:8001/eureka/,http://admin:pwd123@node1.test.com:8002/eureka/,http://admin:pwd123@node3.test.com:8003/eureka/

服务注册

工程结构

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eureka-provider
├── pom.xml
├── src
│   └── main
│       ├── java
│       │   └── com
│       │       └── cloud
│       │           └── provider
│       │               ├── Application.java
│       │               └── www
│       │                   └── SimpleController.java
│       └── resources
│           └── application.properties

Maven配置

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<dependencies>
    <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>
</dependencies>

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

主类示例

  • @EnableDiscoveryClient开始实例自动发现并注册到注册中心
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@EnableDiscoveryClient
@SpringBootApplication
public class Application {

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

}

配置示例

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spring.application.name=server-provider

server.port=7001
spring.http.encoding.charset=utf-8

eureka.client.service-url.defaultZone=http://admin:pwd123@node1.test.com:8001/eureka/,http://admin:pwd123@node1.test.com:8002/eureka/,http://admin:pwd123@node3.test.com:8003/eureka/

服务接口

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@RestController
@RequestMapping(value="/api")
public class SimpleController {

    private final Logger logger = LoggerFactory.getLogger(Application.class);

    @GetMapping(value="/select/{id}", produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
    public ResponseEntity getUserEntry(@PathVariable("id") long id) {
        return ResponseEntity.ok("测试数据:" + id);
    }
    
}

服务启动

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[root@localhost target ]$ java -jar eureka-provider-1.0-SNAPSHOT.jar --server.port=7001 &
[root@localhost target ]$ java -jar eureka-provider-1.0-SNAPSHOT.jar --server.port=7002 &

注册查看

访问注册中心:http://admin:pwd123@node1.test.com:8001

服务消费(Ribbon)

工程结构

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eureka-consumer-ribbon
├── eureka-consumer-ribbon.iml
├── pom.xml
├── src
│   └── main
│       ├── java
│       │   └── com
│       │       └── cloud
│       │           └── consumer
│       │               └── ribbon
│       │                   ├── Application.java
│       │                   └── www
│       │                       └── RibbonController.java
│       └── resources
│           └── application.properties

Maven依赖

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<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>

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

消费示例

主类示例

@EnableDiscoveryClient注解让改应用注册为Eureka客户端应用,在主类中创建RestTemplate的实例,并通过@LoadBalanced开启客户端负载均衡.

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@EnableDiscoveryClient
@SpringBootApplication
public class Application {

    @Bean
    @LoadBalanced
    RestTemplate getRestTemplate() {
        return new RestTemplate();
    }

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

这里访问的PROVIDER.TEST.SIMPLESERVER是服务提供方的服务名(服务名不区分大小写)

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@RestController
@RequestMapping(value="/api/invoke")
public class RibbonController {

    @Autowired
    RestTemplate restTemplate;

    @GetMapping(value="/select/{id}")
    public String remoteInvoke(@PathVariable long id) {
        return restTemplate.getForObject("http://SERVER-PROVIDER/api/select/{0}", String.class, id);
    }
}

配置示例

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server.port=8080
spring.application.name=consumer-ribbon

# 心跳时间，即服务续约间隔时间（缺省为30s）
eureka.instance.lease-renewal-interval-in-seconds=5
# 发呆时间，即服务续约到期时间（缺省为90s）
eureka.instance.lease-expiration-duration-in-seconds=10

### 应用注册信息
eureka.client.service-url.defaultZone=http://admin:pwd123@node1.test.com:8001/eureka/,http://admin:pwd123@node1.test.com:8002/eureka/,http://admin:pwd123@node3.test.com:8003/eureka/

启动访问

注册中心面板

访问请求查看
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[root@localhost target ]$ curl -XGET http://172.30.12.197:8080/api/invoke/select/7
测试数据7

服务消费(Feign)

工程结构

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eureka-consumer-feign
├── pom.xml
├── src
│   └── main
│       ├── java
│       │   └── com
│       │       └── cloud
│       │           └── consumer
│       │               └── feign
│       │                   ├── Application.java
│       │                   ├── service
│       │                   │   └── SimpleFeignService.java
│       │                   └── www
│       │                       └── FeignController.java
│       └── resources
│           └── application.properties

Maven依赖

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<dependencies>
    <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-feign</artifactId>
    </dependency>
</dependencies>

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

消费示例

主类示例

@EnableDiscoveryClient注解让改应用注册为Eureka客户端应用,@EnableFeignClients开启Spring Cloud Feign支持

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@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}
接口调用

定义调用接口,通过@FeignClient注解指定服务名来绑定服务,这里配置的SERVER-PROVIDER是服务提供方的服务名(服务名不区分大小写)

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@FeignClient(name="SERVER-PROVIDER")
public interface SimpleFeignService {

    @GetMapping(value="/api/select/{id}")
    String getUserEntry(@PathVariable("id") long id);
}
Api服务
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@RestController
@RequestMapping(value="/api/invoke")
public class FeignController {

    @Autowired
    private SimpleFeignService simpleFeignService;

    @GetMapping(value="/select/{id}")
    public String remoteInvoke(@PathVariable long id) {
        return simpleFeignService.getUserEntry(id);
    }
}

配置示例

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server.port=9090
spring.application.name=consumer-feign

# 心跳时间，即服务续约间隔时间（缺省为30s）
eureka.instance.lease-renewal-interval-in-seconds=5
# 发呆时间，即服务续约到期时间（缺省为90s）
eureka.instance.lease-expiration-duration-in-seconds=10

### 应用注册信息
eureka.client.service-url.defaultZone=http://admin:pwd123@node1.test.com:8001/eureka/,http://admin:pwd123@node1.test.com:8002/eureka/,http://admin:pwd123@node3.test.com:8003/eureka/

启动访问

注册中心面板

访问请求查看
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[root@localhost target ]$ curl -XGET http://172.30.12.197:9090/api/invoke/select/5
测试数据5