Eureka注册中心

一、创建Eureka注册中心

1. 创建项目Eureka_0720

2.导入依赖

 <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR9</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

3.在项目上新建模块EurkaServer

4.导入依赖

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

5.编写启动器

@EnableEurekaServer
@SpringBootApplication
public class EurekaServer7001 {
    public static void main(String[] args) {
        SpringApplication.run(EurekaServer7001.class, args);
        System.out.println("注册中心启动成功！");
    }
}

6.书写yml配置

server:
  port: 7001
eureka:
  instance:
    hostname: localhost  #主机名
  client:
    register-with-eureka: false #1、不注册自己（不做服务提供者）
    fetch-registry: false #2、不获取配置（不做消费者）
    service-url: #指定注册中心地址，配置集群逗号分隔即可
      defaultZone: http://localhost:7001/eureka

7.访问 http://localhost:7001/

二、创建服务提供者

1.在项目上新建模块Server

2.导入依赖

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

3.编写启动器

@EnableEurekaClient
@SpringBootApplication
public class Server8001 {
    public static void main(String[] args) {
        SpringApplication.run(Server8001.class, args);
    }
}

4.书写yml配置

server:
  port: 8001
spring:
  application:
    name: cloud-payment-service  #给服务起个名字
eureka:
  client:
    register-with-eureka: true #向注册中心注册自己
    fetch-registry: true  #可以获取注册信息
    service-url:
      defaultZone: http://localhost:7001/eureka

5.提供一个外部接口然后测试

@RestController
@RequestMapping("/test")
public class TestController {
    @Value("${server.port}")
    private String port;

    @RequestMapping("/test1")
    public String test1(){
        return String.format("/port==>%s,service ok",port);
    }
}

6.先启动注册中心，然后启动服务提供者，然后查看注册中心能看到服务提供者即为成功

7.测试外部接口是否正常

8.复制多个sever模拟分布式部署

9.找到 VM options，不同版本界面可能不相同，添加 -Dserver.port配置端口

10.启动多个server

三、创建消费者

1.新建模块Client

2.导入依赖

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

3.编辑启动器

@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
public class Client80 {
    public static void main(String[] args) {
        SpringApplication.run(Client80.class, args);
    }
}

4.熟悉yml配置

server:
  port: 80
spring:
  application:
    name: cloud-order-service
eureka:
  client:
    register-with-eureka: true #向注册中心注册自己
    fetch-registry: true  #可以获取注册信息
    service-url:
      defaultZone: http://localhost:7001/eureka

5.RestTemplate配置

在配置类中添加Bean声明即可：

@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
public class Client80 {
    public static void main(String[] args) {
        SpringApplication.run(Client80.class, args);
    }

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

6.通过注册中心拉取服务提供者列表 进行随机访问

@RestController
public class TestController {

    @Autowired
    private RestTemplate restTemplate;

    @Autowired
    private DiscoveryClient discoveryClient;

    @GetMapping("/test")
    public String test() {
        List<ServiceInstance> serverList = discoveryClient.getInstances("cloud-payment-service");
        System.out.println(serverList);
        int index = new Random().nextInt(serverList.size());
        ServiceInstance serviceInstance = serverList.get(index);
        String url = String.format("http://%s:%s/test/get", serviceInstance.getHost(), serviceInstance.getPort());
        return restTemplate.getForObject(url, String.class);
    }
}

server中

@RestController
@RequestMapping("/test")
public class TestController {
    @Value("${server.port}")
    private String port;

    @RequestMapping("/test1")
    public String test1(){
        return String.format("/port==>%s,service ok",port);
    }

    @RequestMapping("/get")
    public String test() {
        return port;
    }
}

7.测试

访问消费者的test接口

多次刷新，访问的提供者是随机的，可以通过端口判断