spring cloud 服务提供与调用

直接用上一篇搭建好的spring cloud注册中心集群，编写服务提供者provider和服务消费者consumer

服务提供Provider

pom.xml

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.springcloud</groupId>
    <artifactId>provider</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.RELEASE</spring-cloud.version>
    </properties><!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-dependencies -->


    <dependencies>

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

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

    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

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

</project>

application.yml

spring:
  application:
    name: provider　　//应用名称，即注册中心里注册的名称

server:
  port: 8050

eureka:
  client:
    serviceUrl:
      defaultZone: http://peer2:8001/eureka/,http://peer3:8002/eureka/

启动类

@SpringBootApplication
@EnableDiscoveryClient       //表明项目具有服务注册的功能，可以在注册中心看到
public class ApplicationStarter {

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

}

Controller

@RestController
@RequestMapping("/provider")
public class HelloController {

    @GetMapping("/hello")
    public Map hello(){

        Map<String,String> map=new HashMap<>();
        map.put("messages","Hello world!");

        return map;

    }
}

服务调用Consumer

pom.xml

与服务提供Provider一致

application.yml

spring:
  application:
    name: consumer

//默认8080端口

eureka:
  client:
    service-url:
      defaultZone: http://peer2:8001/eureka/,http://peer3:8002/eureka/

启动类

@SpringBootApplication
@EnableDiscoveryClient
public class ApplicationStart {

    @Bean
    @LoadBalanced
    RestTemplate restTemplate(){
        return new RestTemplate();   //利用restTemplate去查找服务并调用它
    }

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

Controller

@RestController
@RequestMapping("/message")
public class MessageController {

    @Autowired
    RestTemplate restTemplate;


    @GetMapping("/hello")
    public Map hello(){
      return  restTemplate.getForObject("http://PROVIDER/provider/hello", HashMap.class);    //这里通过注册名称调用，不是域名
    }

}

启动Provider和Consumer，在注册中心可以看到：

 浏览器输出： localhost:8080/message/hello

一个最基本的springcloud集群版的Hello World完成了