1. 使用

• 1.1 父工程引入对应版本的依赖,注意springboot , cloud, cloud-alibaba对应版本

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
                <version>2.3.2.RELEASE</version>
            </dependency>

            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.2.6.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

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

• 1.2 创建服务提供者

• 依赖

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
    </dependencies>

• 配置注册中心的地址和namespace, 要将该服务注册到那个注册中心的哪个环境

spring:
  application:
    name: provider
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
        namespace: e7a8ccc6-10df-46cd-88a0-cf54157e8ace  // 该namespace为dev

• 开启服务注册功能

@EnableDiscoveryClient
@SpringBootApplication
public class ProviderApplication {

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

}

• 创建api对外暴露接口

@RestController
@RequestMapping("echoController")
public class EchoController {

    @Value("${server.port}")
    private int port;

    @GetMapping("/echo/{string}")
    public String echo(@PathVariable("string") String string){
        return "this is provider at port:" + port + ", you want me to echo : "+ string;
    }
}

1.3 创建服务消费者(调用方)

同样要将其注册到注册中心，然后通过注册中心发现被调用方

• restTemplate方式完成调用

spring:
  application:
    name: consumer
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
        namespace: e7a8ccc6-10df-46cd-88a0-cf54157e8ace // namespace, group与provider相对应，否则将注册到不同的组，那么无法发现服务实例

@EnableDiscoveryClient
@SpringBootApplication()
public class ComsumerApplication {......}

简单通过restTemplate调用， restTemplate通过@Ribbon添加负载均衡

@RestController()
@RequestMapping("/something")
@RefreshScope //@RefreshScope 实现配置自动更新
public class SaySomethingController {

    @Value("${something:0}")
    private Integer something;

    @Autowired
    private DataSource dataSource;

    @Autowired
    RestTemplate restTemplate;

    @GetMapping("/echo/{str}")
    public String echo(@PathVariable("str") String str){
        return restTemplate.getForObject("http://provider/echoController/echo/"+str, String.class);
    }
}

1.4 测试

启动服务，创建两个provider实例和一个consumer实例, 完成测试

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