【微服务架构 - 08 - Spring Cloud】03 创建服务提供者

约定不等于承诺〃 2022-03-22 15:14 245阅读 0赞

## 概述 ##

--------------------

当 Client 向 Server 注册时，它会提供一些元数据，例如主机和端口，URL，主页等。  
Eureka Server 从每个 Client 实例接受心跳消息。如果心跳超时，则通常将该实例从注册 Server 中删除。

## POM ##

--------------------

<?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>
    
        <parent>
            <groupId>com.yuu</groupId>
            <artifactId>hello-spring-cloud-dependencies</artifactId>
            <version>1.0.0-SNAPSHOT</version>
            <relativePath>../hello-spring-cloud-dependencies/pom.xml</relativePath>
        </parent>
    
        <artifactId>hello-spring-cloud-service-admin</artifactId>
        <packaging>jar</packaging>
    
        <name>hello-spring-cloud-service-admin</name>
        <inceptionYear>2019-Now</inceptionYear>
    
        <dependencies>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            
    
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
            </dependency>
            
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <configuration>
                        <mainClass>com.funtl.hello.spring.cloud.service.admin.ServiceAdminApplication</mainClass>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    </project>

## Application ##

--------------------

通过注解 `@EnableEurekaClient` 表明自己是一个 Eureka Client

package com.yuu.hello.spring.cloud.service.admin;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    
    /**
     * @Classname ServiceAdminApplication
     * @Date 2019/1/28 22:50
     * @Created by Yuu
     */
    @SpringBootApplication
    @EnableEurekaClient
    public class ServiceAdminApplication {
        public static void main(String[] args) {
            SpringApplication.run(ServiceAdminApplication.class, args);
        }
    }

## application.yml ##

--------------------

spring:
      application:
        name: hello-spring-cloud-service-admin
    
    server:
      port: 8762
    eureka:
      client:
        servcieUrl:
          defaultZone: http://localhost:8761/eureka/

**注意：** 需要指明 `spring.application.name`，因为这个很重要，这在以后的服务与服务之间相互调用一般都是根据这个 `name`

## Controller ##

--------------------

package com.yuu.hello.spring.cloud.service.admin.controller;
    
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    /**
     * @Classname AdminController
     * @Date 2019/1/28 23:00
     * @Created by Yuu
     */
    @RestController
    public class AdminController {
    
        @Value("${server.port}")
        private String port;
    
        @RequestMapping(value = "hi", method = RequestMethod.GET)
        public String sayHi(@RequestParam(value = "message") String message) {
            return String.format("Hi, your message is : %s : i am from port: %s", message, port);
        }
    }

启动工程，打开 [http://localhost:8761][http_localhost_8761]，即 Eureka Server 的网址

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NTgxMjgy_size_16_color_FFFFFF_t_70]

你会发现一个服务已经注册在服务中了，服务名为 `HELLO-SPRING-CLOUD-SERVICE-ADMIN` ，端口为 `8762`

这是打开 [http://localhost:8762/hi?message=HelloSpringCloud，你会在浏览器上看到：][http_localhost_8762_hi_message_HelloSpringCloud]

![在这里插入图片描述][20190128232403197.png]

[http_localhost_8761]: http://localhost:8761
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NTgxMjgy_size_16_color_FFFFFF_t_70]: /images/20220322/1a04f1becc814776a278bb421dbffd5a.png
[http_localhost_8762_hi_message_HelloSpringCloud]: http://localhost:8762/hi?message=HelloSpringCloud%EF%BC%8C%E4%BD%A0%E4%BC%9A%E5%9C%A8%E6%B5%8F%E8%A7%88%E5%99%A8%E4%B8%8A%E7%9C%8B%E5%88%B0%EF%BC%9A
[20190128232403197.png]: /images/20220322/4216ec2421534d2fa90c604a46fc3788.png