1. 服务注册

1.1 新建module,修改pom文件

创建服务提供者工程(module名为sca-provider），继承parent工程(01-sca),其pom.xml文件内容如下：

<?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">
    <parent>
        <artifactId>01-sca</artifactId>
        <groupId>com.jt</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>sca-provider</artifactId>

    <dependencies>
        <!--Web服务-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--服务的注册和发现(我们要将服务注册到nacos)-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
    </dependencies>
</project>

1.2 创建配置文件

创建并修改配置文件application.yml(或者application.properties)，实现服务注册，关键代码如下：

server:
   port: 8081
spring:
  application:
    name: sca-provider
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848

1.3 创建启动类,并定义处理请求的控制层对象和方法

package com.jt;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author 小新
 * @date 2021/08/16 17:04
 */
@SpringBootApplication
public class ProviderApplication {
    public static void main(String[] args) {
        SpringApplication.run(ProviderApplication.class, args);
    }

    /**定义Controller对象(这个对象在spring mvc中给他的定义是handler),
     * 基于此对象处理客户端的请求*/
    @RestController
    public class ProviderController{
        //@Value默认读取项目配置文件中配置的内容
        @Value("${server.port:8080}")
        private String server;
        //http://localhost:8081/provider/echo/msg
       @GetMapping("provider/echo/{msg}")
        public String doRestEcho(@PathVariable String msg){
            return server+"say hello"+msg;
        }
    }
}

2. 服务发现及调用

2.1 新建module,修改pom文件

创建服务消费者（module名为sca-consumer），继承parent工程（01-sca），其pom.xml文件内容如下：

<?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">
    <parent>
        <artifactId>01-sca</artifactId>
        <groupId>com.jt</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>sca-consumer</artifactId>

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

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

</project>

2.2 创建配置文件

修改配置文件application.yml，关键代码如下：

server:
  port: 8090
spring:
  application:
    name: sca-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #从哪里去查找服务

2.3 创建启动类并实现服务消费

package com.jt;
@SpringBootApplication
public class ConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(ConsumerApplication.class,args);
    }
    /**创建RestTemplate对象,然后基于此对象进行远程服务调用*/
    @Bean
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
    @RestController
    public class ConsumerController{

        @Value("${spring.application.name}")
        private String appName;
        @Autowired
        private RestTemplate restTemplate;
        
        /**
         * 直接调用(非负载均衡方式)
         * http://localhost:8090/consumer/echo
         * @return
         */
        @GetMapping("/consumer/echo")
        public String doRestEcho(){
            String url="http://localhost:8081/provider/echo/"+appName;
            return restTemplate.getForObject(url,String.class);
        }
    }
}