SpringCloud学习一-搭建netflix-eureka微服务集群

1.打开官网稍微学习一下，了解一下spring cloud是个什么东西，大概有哪些组件等

https://spring.io/projects/spring-cloud 

https://docs.spring.io/spring-cloud-netflix/docs/current/reference/html/

2.新建项目

打开网址：https://start.spring.io/

选择需要引入的组件，然后下载下来即可

3.更改项目结构

为了测试的方便，需将项目结构更改为多模块的项目。

步骤如下：

(1) 依次新建子模块register-center/provider/consumer，删除父模块中多余的src、target等文件夹

(2) 修改父模块的pom文件：仅保留<dependencyManagement>配置节，<dependencies>配置节全部注释掉，因为可在子模块按需添加依赖。

 (3) 修改register-center的pom中的依赖配置

 <dependencies>
        <!-- Eureka注册中心 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
    </dependencies>

(4) 修改provider和consumer的pom中依赖配置

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

4.新建相应的测试类和配置文件

4.1 register-center模块

启动类

package com.hdwang.springcloudtest.registercenter;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class Application {

    /**
     * 运行点对点模式（集群模式）时，通过添加VM参数启动不同的注册中心节点实例
     * 例如：-Dspring.profiles.active=peer2
     *
     * @param args
     */
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

yml配置

spring:
  application:
    #应用名
    name: register-center
  freemarker:
    template-loader-path: classpath:/templates/
    prefer-file-system-access: false
  #激活的配置，可运行时添加参数进行修改 -Dspring.profiles.active=peer2
  profiles:
    active: peer1

# #Eureka独立模式配置，仅有一个注册中心节点
#server:
#  port: 8090
#eureka:
#  instance:
#    hostname: localhost
#  client:
#    #仅仅作为注册中心，既不提供服务也不订阅服务
#    registerWithEureka: false
#    fetchRegistry: false
#    #注册中心地址
#    serviceUrl:
#      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/


# Eureka点对点模式，保证注册中心高可用，注册的实例信息会在点与点之间相互同步
eureka:
  client:
    serviceUrl:
      defaultZone: http://peer1.com:8091/eureka/,http://peer2.com:8092/eureka/,http://peer3.com:8093/eureka/

---
#每个注册中心节点不同的配置
spring:
  profiles: peer1
server:
  port: 8091
eureka:
  instance:
    #在本机hosts中配置即可
    hostname: peer1.com

---
spring:
  profiles: peer2
server:
  port: 8092
eureka:
  instance:
    hostname: peer2.com

---
spring:
  profiles: peer3
server:
  port: 8093
eureka:
  instance:
    hostname: peer3.com

4.2 provider模块

启动类

package com.hdwang.springcloudtest.provider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    /**
     * 运行时添加VM参数: -Dserver.port=8082可以启动多个provider实例
     *
     * @param args
     */
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

服务注册类

package com.hdwang.springcloudtest.provider.restservice;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * 注册的服务
 */
@RestController
public class RestService {
    /**
     * 日志
     */
    private static final Logger LOG = LoggerFactory.getLogger(RestService.class);

    @RequestMapping("/sayHello")
    public String sayHello(String name) {
        LOG.info("sayHello was called");
        return "hello, " + name;
    }
}

yml配置

spring:
  application:
    #应用名，也是eureka的服务名
    name: provider
  freemarker:
    template-loader-path: classpath:/templates/
    prefer-file-system-access: false

server:
  #运行时，添加参数-Dserver.port=8082运行新的provider实例
  port: 8081

eureka:
  client:
    #注册中心地址
    serviceUrl:
      #注册中心独立模式
      #defaultZone: http://localhost:8090/eureka/
      #注册中心点对点模式
      defaultZone: http://peer1.com:8091/eureka/,http://peer2.com:8092/eureka/,http://peer3.com:8093/eureka/

4.3 consumer配置

启动类

package com.hdwang.springcloudtest.consumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

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

}

服务调用测试类

package com.hdwang.springcloudtest.consumer.controller;

import com.netflix.appinfo.InstanceInfo;
import com.netflix.discovery.EurekaClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import java.util.*;

/**
 * 测试
 */
@RestController
public class TestController {

    /**
     * 使用服务名才能负载均衡，不能使用直接使用地址
     */
    private static final String REST_URL_PREFIX = "http://provider";

    @Autowired
    private EurekaClient discoveryClient;

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/testGet")
    public String testGet() {
        ResponseEntity<String> res = restTemplate.getForEntity(REST_URL_PREFIX + "/sayHello?name={1}", String.class, getName());
        return res.getBody();
    }

    @GetMapping("/testPost")
    public String testPost() {
        MultiValueMap<String, Object> params = new LinkedMultiValueMap<String, Object>();
        params.add("name", getName());

//        HttpHeaders headers = new HttpHeaders();
//        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

        HttpEntity< MultiValueMap<String, Object>> request = new HttpEntity<>(params, null);
        ResponseEntity<String> res = restTemplate.postForEntity(REST_URL_PREFIX + "/sayHello", request, String.class);
        return res.getBody();
    }

    private String getName() {
        List<String> greetings = Arrays.asList("Bob", "Alice", "Jack");
        Random rand = new Random();
        int randomNum = rand.nextInt(greetings.size());
        return greetings.get(randomNum);
    }
}

RestTemplate负载均衡配置类

package com.hdwang.springcloudtest.consumer.config;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class RestTemplateConfig {

    /**
     * 构建有负载均衡功能的RestTemplate实例对象
     *
     * @return RestTemplate实例对象
     */
    @Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

yml配置

spring:
  application:
    #应用名，也是Eureka的服务名
    name: cosumer

server:
  port: 8088

eureka:
  client:
    #注册中心地址
    serviceUrl:
      #注册中心独立模式
      #defaultZone: http://localhost:8090/eureka/
      #注册中心点对点模式
      defaultZone: http://peer1.com:8091/eureka/,http://peer2.com:8092/eureka/,http://peer3.com:8093/eureka/

5.运行测试

5.1本机hosts配置

127.0.0.1 peer1.com
127.0.0.1 peer2.com
127.0.0.1 peer3.com

5.2 编辑运行配置

三个注册中心节点运行配置

 

 

 两个服务提供者的运行配置

 

 5.3 运行程序

(1) 启动注册中心

依次启动RegisterCenter1->RegisterCenter2->RegisterCenter3，启动成功后，可访问http://localhost:8091/ 或 http://localhost:8092/ 或 http://localhost:8093/ 查看是否启动成功

 (2)启动服务提供者provider

 依次启动Provider1->Provider2, 随便访问一个注册中心地址首页即可查看状态，如下图

 (3) 启动消费者cosumer

 (4) 在浏览器中进行测试

 测试地址：http://localhost:8088/testPost  /   http://localhost:8088/testGet

 (5) 在Provider1/Provider2的控制台中可以看到输出结果

2021-04-07 15:26:56.043  INFO 8796 --- [nio-8081-exec-1] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:26:58.860  INFO 8796 --- [nio-8081-exec-2] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:26:59.535  INFO 8796 --- [nio-8081-exec-3] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:26:59.925  INFO 8796 --- [nio-8081-exec-4] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:27:00.266  INFO 8796 --- [nio-8081-exec-5] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:27:00.663  INFO 8796 --- [nio-8081-exec-6] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:27:00.938  INFO 8796 --- [nio-8081-exec-7] c.h.s.provider.restservice.RestService   : sayHello was called

2021-04-07 15:26:58.602  INFO 17828 --- [nio-8082-exec-1] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:26:59.194  INFO 17828 --- [nio-8082-exec-2] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:26:59.737  INFO 17828 --- [nio-8082-exec-3] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:27:00.109  INFO 17828 --- [nio-8082-exec-4] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:27:00.414  INFO 17828 --- [nio-8082-exec-5] c.h.s.provider.restservice.RestService   : sayHello was called
2021-04-07 15:27:00.815  INFO 17828 --- [nio-8082-exec-6] c.h.s.provider.restservice.RestService   : sayHello was called

恭喜！至此，Spring Clound 微服务集群框架您已经搭建成功！

附录

github地址：https://github.com/hdwang123/springcloudtest

参考文章：

https://www.zhihu.com/question/283286745/answer/763040709

https://www.cnblogs.com/qdhxhz/p/9357502.html

https://www.cnblogs.com/cjsblog/p/8005766.html

https://blog.csdn.net/weixin_44448094/article/details/88535475