spring-clound 学习打卡2：简单入门-服务消费，基于【rest+ribbon】【Greenwich.SR1版本】

àì夳堔傛蜴生んèń 2022-02-16 10:41 82阅读 0赞

# spring-clound 学习打卡2：简单入门-服务消费，基于【rest+ribbon】 【Greenwich.SR1版本】 #

# 一，工程传送门。 #

[https://github.com/unnunique/SpringCloundDakaLearning/tree/master/Chapter-2][https_github.com_unnunique_SpringCloundDakaLearning_tree_master_Chapter-2]

# 二，简介。 #

ribbon是一个负载均衡客户端，可以很好的控制htt和tcp的一些行为。Feign默认集成了ribbon。  
本文通俗地说，主要是用来调用注册在注册中心的服务。用基于ribbon的方式。

# 三，环境准备，首先启动上一篇中的server 和两个client. #

启动后，通过网页访问注册中心，如下，可以看到注册中心注册有两个相同的服务，组成了一个小的集群。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Vhc2VzX3N0b25l_size_16_color_FFFFFF_t_70]

# 四，上手工程，演示访问注册中心的服务。 #

## 4.1 首先是新建一个maven 子模块，maven pom 文件如下。 ##

<?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>parent</artifactId>
            <groupId>com.sydney.dream.springclound</groupId>
            <version>1.0.0</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
    
        <artifactId>chapter-2</artifactId>
        
        <properties>
            <java.version>1.8</java.version>
            <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
        </properties>
    
        <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>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </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>

## 4.2 然后配置项目properties ##

server.port=8764
    
    spring.application.name=service-consumer-client-demo1
    
    eureka.instance.hostname=localhost
    eureka.client.register-with-eureka=true
    eureka.client.fetch-registry=true
    eureka.client.service-url.default-zone=http://${eureka.instance.hostname}:${server.port}/eureka/
    
    remote.eureka.servername=srvice-clientdemo

## 4.3 编写启动类 ##

注意添加如下两个注释：  
@EnableEurekaClient  
@EnableDiscoveryClient  
并且注册一个restTemplate Bean

> @Bean  
> @LoadBalanced  
> RestTemplate restTemplate() \{  
> return new RestTemplate();  
> \}

package com.sydney.dream.chapter2;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.client.loadbalancer.LoadBalanced;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    import org.springframework.context.annotation.Bean;
    import org.springframework.web.client.RestTemplate;
    
    @SpringBootApplication
    @EnableEurekaClient
    @EnableDiscoveryClient
    public class RibbonClinet { 
        public static void main(String[] args) { 
            SpringApplication.run(RibbonClinet.class, args);
        }
    
        @Bean
        @LoadBalanced
        RestTemplate restTemplate() { 
            return new RestTemplate();
        }
    }

## 4.4, 编写Service 类 ##

注意这里的$\{remote.eureka.servername\}， 值的是注册到注册中心的服务的名字。 本文是： service-consumer-client-demo1

package com.sydney.dream.chapter2;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.stereotype.Service;
    import org.springframework.web.client.RestTemplate;
    
    @Service
    public class HelloService { 
        @Autowired
        RestTemplate restTemplate;
    
        @Value("${remote.eureka.servername}")
        private String serverName;
    
        public String hiService(String name) { 
            return restTemplate.getForObject("http://" + serverName + "/hi?name="+name,String.class);
        }
    }

## 4.5 编写controller 类。 ##

package com.sydney.dream.chapter2;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class HelloWorldController {
        @Autowired
        HelloService helloService;
    
        @GetMapping(value = "/hi")
        public String hi(@RequestParam String name) {
            return helloService.hiService( name );
        }
    }

## 4.6 启动服务 ##

通过如下链接访问几次，可以看到访问的时候，实现了应该是轮询的负载均衡的情况。  
[http://localhost:8764/hi?name=didi][http_localhost_8764_hi_name_didi]  
相应结果。  
hi didi,i am from port:8762  
hi didi,i am from port:8763

## 4.7 至此，入门打卡篇2， Done ##

# 五，此时的架构 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Vhc2VzX3N0b25l_size_16_color_FFFFFF_t_70 1]

[https_github.com_unnunique_SpringCloundDakaLearning_tree_master_Chapter-2]: https://github.com/unnunique/SpringCloundDakaLearning/tree/master/Chapter-2
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Vhc2VzX3N0b25l_size_16_color_FFFFFF_t_70]: /images/20220216/ec07bc85fca64467b2602fe961efb630.png
[http_localhost_8764_hi_name_didi]: http://localhost:8764/hi?name=didi
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Vhc2VzX3N0b25l_size_16_color_FFFFFF_t_70 1]: /images/20220216/dbf3209132b744bc836ff12cf1d013a2.png