SpringCloudNetfilx入门

整体框架

由于整个微服务使用springcloud进行管理，所以采用maven聚合工程

导包

最好使用父项目进行版本控制

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Hoxton.SR4</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.2.5.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

注意点：maven中和Java类似没有多继承这个概念，间接实现多继承就可以使用import对包进行导入，这样子包就能继承版本控制

注册中心

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

客户端（服务提供者也是客户端）

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
    <!--实现负载均衡-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
    </dependency>
    <!--显示info信息-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
</dependencies>

application配置

注册中心

server:
  port: 8000
eureka:
  client:
    register-with-eureka: false # 不讲自己注册进注册中心
    fetch-registry: false # 不拉取服务

在springboot应用中开启EurekaServer

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

服务提供者或消费者

server:
  port: 8081
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8000/eureka # 服务中心的地址，','隔开可以写多个实现集群
  instance:
    instance-id: consumer-port:8081 # status的名称
spring:
  application:
    name: consumer # 服务的名称
debug: true
# 配置自己的信息
info:
  app.name: roderick

在springboot应用中开启EurekaServer

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

消费者调用提供者Rest接口

这里使用RestTemplate连接客户端

@RestController
public class MainController {
    RestTemplate restTemplate;
    DiscoveryClient discoveryClient;
    private static final String URL = "http://localhost:8100";
    private static final String ID_URL = "http://CONSUMER"; //通过id直接获取（内部玩法）

    @Autowired
    public void setRestTemplate(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }

    @Autowired
    public void setDiscoveryClient(DiscoveryClient discoveryClient) {
        this.discoveryClient = discoveryClient;
    }

    @GetMapping("/get/{id}")
    public String getUser(@PathVariable("id") String id) {
        return restTemplate.getForObject(ID_URL + "/test/" + id, String.class);
    }

    @GetMapping("/services")
    public String getService() {    //获取服务列表
        Map<String, List<ServiceInstance>> map = new HashMap<>();
        List<String> services = discoveryClient.getServices();
        for (String service : services) {
            List<ServiceInstance> instances = discoveryClient.getInstances(service);
            map.put(service, instances);
        }
        return map.toString();
    }
}

代码中将URL写死是不行的，我们可以使用DiscoveryClient获取或者直接将服务名作为url，通过解析可以获取到服务的真实地址